Land Rover L322 Range Rover Workshop Manual

Land Rover
Marca
Land Rover
Modelo
L322 Range Rover
Categoría
Carros
Tipo
Workshop Manual

Este manual también es adecuado para

Workshop Manual
System Description & Operation
NRRWM 21/11/01 11:21 am Page 1
2002MY
WORKSHOP MANUAL - SYSTEM
DESCRIPTION AND OPERATION
LRL0424ENG (2nd Edition)
Published by Land Rover – Technical Service
© 2002 Land Rover
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form,
electronic, mechanical, recording or other means without written prior permission from Land Rover.
CONTENTS
CONTENTS 1
ENGINE – Td6 12-1-1
Td 6 – External View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-1-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1-2
ENGINE - V8 12-2-1
V8 – External View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-2-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2-2
ENGINE MANAGEMENT SYSTEM – Td6 18-1-1
Engine Management Component Location – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-1-2
Engine Management Component Location – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-1-4
Engine Management Control Diagram – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1-6
Engine Management Control Diagram – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1-8
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1-10
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1-35
Cruise Control Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-1-39
Cruise Control, Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-1-40
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1-42
ENGINE MANAGEMENT SYSTEM – V8 18-2-1
Engine Management Component Location – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-2-2
Engine Management Component Location – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-2-4
Engine Management Control Diagram – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-6
Engine Management Control Diagram – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-8
Bosch ME 7.2 Engine Management System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-10
Variable Camshaft Control Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-41
VCC System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-42
Cruise Control Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-2-50
Cruise Control System Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-2-51
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-53
EVAP System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-55
Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2-56
FUEL DELIVERY SYSTEM – Td6 19-1-1
Td6 Fuel Delivery Component Location – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1-1
Td6 Fuel Delivery Component Location – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1-2
Td6 Fuel System Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19-1-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1-6
FUEL DELIVERY SYSTEM – V8 19-2-1
Fuel Delivery System Component Location (All Except NAS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2-2
Fuel Delivery System Component Location (NAS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2-4
V8 Fuel Delivery System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19-2-6
CONTENTS
2CONTENTS
COOLING SYSTEM – Td6 26-1-1
Td6 Cooling System – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1-2
Td6 Cooling System – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1-4
Td6 Coolant Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1-6
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1-8
COOLING SYSTEM – V8 26-2-1
V8 Cooling System – Sheet 1 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-2
V8 Cooling System – Sheet 2 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-4
V8 Coolant Flow – Models With FBH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-6
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-8
MANIFOLDS AND EXHAUST SYSTEM – Td6 30-1-1
Exhaust Manifold Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-2
Inlet Manifold Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-4
Exhaust System Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-6
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-8
MANIFOLDS AND EXHAUST SYSTEM – V8 26-2-1
Exhaust Manifold Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-1
Inlet Manifold Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-2
Exhaust System Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2-6
TRANSFER BOX 41-1
Transfer Box Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41-1
Transfer Box Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41-2
Transfer Box Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41-6
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41-20
AUTOMATIC TRANSMISSION – GM 5L40-E 44-1-1
GM 5L40-E Automatic Transmission Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1-2
GM 5L40-E Automatic Transmission – Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1-4
GM 5L40-E Automatic Transmission – Sectional View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1-6
GM 5L40-E Automatic Transmission – Valve Block and Solenoid Valves . . . . . . . . . . . . . . . . . . 44-1-8
GM 5L40-E Automatic Transmission – Fluid Pump Cover Plate Assembly . . . . . . . . . . . . . . . . . 44-1-10
GM 5L40-E Automatic Transmission Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1-12
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1-14
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1-58
CONTENTS
CONTENTS 3
AUTOMATIC TRANSMISSION – ZF 5HP24 44-2-1
ZF 5HP24 Automatic Transmission Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-2-2
ZF 5HP24 Automatic Transmission – Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-2-4
ZF 5HP24 Automatic Transmission – Sectional View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-2-6
ZF 5HP24 Automatic Transmission – Valve Block and Solenoid Valves . . . . . . . . . . . . . . . . . . . . 44-2-8
ZF 5HP24 Automatic Transmission Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-2-10
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-2-12
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-2-50
DRIVE AND PROPELLER SHAFTS 47-1
Drive and Propeller Shafts – Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47-2
FINAL DRIVE 51-1
Differentials – Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51-2
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51-10
STEERING 57-1
Steering Component Location – Td6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57-1
Steering Component Location – V8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57-2
Steering Control Diagram – Servotronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57-3
Steering Control Diagram – Column Adjustment – Without Memory . . . . . . . . . . . . . . . . . . . . . . . 57-4
Steering Control Diagram – Column Adjustment – With Memory. . . . . . . . . . . . . . . . . . . . . . . . . .57-5
Steering Control Diagram – Column Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57-6
Steering Control Diagram – Steering Wheel Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57-8
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57-9
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57-22
SUSPENSION 60-1
Suspension Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60-1
Suspension Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60-2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60-3
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60-27
BRAKES 70-1
Braking System Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70-2
Front Brake Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-4
Rear Brake Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70-5
Foundation Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-6
Dynamic Stability Control System Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-12
Dynamic Stability Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-14
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-26
Hand Brake Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70-32
Hand Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-34
CONTENTS
4CONTENTS
RESTRAINT SYSTEMS 75-1
Front Seat Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-1
Rear Seat Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-2
SRS Component Layout – Sheet 1 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-3
SRS Component Layout – Sheet 2 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-5
SRS Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-18
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75-20
DOORS 76-1-1
Front Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-1-1
Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-1-2
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-1-10
INTERIOR TRIM COMPONENTS 76-3-1
Interior Mirror . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-3-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-3-2
SEATS 76-5-1
Front Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-5-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-5-2
Seat Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-5-8
SUNROOF 76-6-1
Sunroof Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-6-1
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-6-2
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76-6-3
AIR CONDITIONING 82-1
Refrigerant System Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-1
Heater Assembly and Ducting Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-2
Control System Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-4
FBH System Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-5
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-6
A/C Control Diagram – Low Line System, Sheet 1 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-32
A/C Control Diagram – Low Line System, Sheet 2 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-34
A/C Control Diagram – High Line System, Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-36
A/C Control Diagram – High Line System, Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-38
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-40
WIPERS AND WASHERS 84-1
Wiper and Washer System Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84-2
Wipers and Washers Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84-6
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84-18
CONTENTS
CONTENTS 5
CHARGING AND STARTING 86-1-1
Charging and Starting Component Location – Td6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-1-1
Charging and Starting Component Location – V8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-1-2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-1-3
LIGHTING 86-2-1
Exterior Lighting Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-2-2
Exterior Lighting Control Diagram – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-2-4
Exterior Lighting Control Diagram – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-2-6
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-2-8
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-2-27
Interior Lighting Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-2-32
Interior Lighting Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-2-34
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-2-36
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-2-38
BODY CONTROL UNIT 86-3-1
BCU Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-3-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-3-2
COMMUNICATION DATA BUSES 86-4-1
Communication Data Buses Control Diagram – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-4-2
Communication Data Buses Control Diagram – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-4-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-4-6
SECURITY 86-5-1
Locking and Alarm Component Layout – Sheet 1 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-5-1
Locking and Alarm Component Layout – Sheet 2 of 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-5-2
Immobilisation Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-5-3
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-5-4
Alarm and Locking Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-5-16
Immobilisation Control Diagram – Diesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-5-18
Immobilisation Control Diagram – Petrol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-5-19
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-5-20
WINDOWS 86-6-1
Windows Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-6-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-6-2
Windows Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-6-6
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-6-8
CONTENTS
6CONTENTS
ENTERTAINMENT AND INFORMATION SYSTEMS 86-8-1
MID Audio System Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-2
MID Audio System Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-4
Multi-Function Display Audio Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-6
Multi-Function Display Audio Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-8
Screen Aerial Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-10
Speaker System Component Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-11
Base Speaker Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-12
Power Amplifier Speaker System Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-14
DSP Amplifier Speaker System Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-16
Audio Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-18
Navigation System Component Location (Except Japan) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-37
Navigation System Control Diagram (Except Japan) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-38
Navigation System Component Location (Japan Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-40
Navigation System Control Diagram (Japan Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-42
New Range Rover Navigation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-44
Telephone System Component Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-55
Telephone System Control Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-56
Telecommunication System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-58
Voice Recognition System Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-8-63
DRIVING AIDS 86-10-1
Park Distance Control Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-1
PDC Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-3
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-6
Tyre Pressure Monitoring Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-8
TPM Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-10
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-12
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-10-15
INSTRUMENTS 88-1
Instrument Pack – Front View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-1
Instrument Pack – Front View – NAS Only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-2
Instrument Pack – Control Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-4
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-6
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-31
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-1
ENGINE – Td 6DESCRIPTION AND OPERATION
Td 6 – External View
M12 7758A
ENGINE – TD6
12-1-2 DESCRIPTION AND OPERATION
Description
General
The Td6 diesel engine is a 3.0 litre, 6 cylinder, in-line direct injection unit, with 4 valves per cylinder, operated by two
overhead camshafts. The engine emissions comply with ECD3 (European Commission Directive) legislative
requirements and employs a catalytic converter, electronic engine management control, positive crankcase
ventilation and exhaust gas recirculation to limit the emission of pollutants. The unit is water cooled and turbo-
charged. The fuel injection system features common rail technology.
The cylinder block is of cast iron construction with a cast aluminium stiffening plate bolted to the bottom of the block
to improve lower structure rigidity. The cylinder head is cast aluminium with a moulded plastic camshaft cover. The
single-piece oil sump is also cast aluminium. The exhaust manifold is mounted on the right side of the engine and a
moulded plastic acoustic cover is fitted over the upper engine to reduce engine generated noise.
To reduce the level of transmitted engine vibration to the vehicle body, the engine is mounted on two hydraulically
damped mountings, fitted between the engine support brackets and engine sub-frame. These are controlled by the
Engine Control Module (ECM).
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
Technical Features
The technical features include:
l In-line 6–cylinder engine with a cast iron crankcase
l Plastic cylinder head cover
l Light alloy cylinder head
l 4-valve technology with centrally arranged fuel injector
l Valves and springs identical to the Td4
l Plastic manifold based on two-shell weld technology
l Exhaust turbocharger, with Variable Nozzle Turbine (VNT)
l Compression ratio 18:1
l Common rail fuel injection system
l High pressure fuel pump
l Cooling duct pistons with central crown bowl
l Electronically controlled Exhaust Gas Recirculation (EGR)
l Exhaust re-treatment by means of a diesel specific oxidation catalytic converter and primary catalytic converter
l Switchable hydraulic engine mounts
l 7-blade cooling fan with viscous clutch drive
l Engine cut out begins at 4000 rpm. The cutout limit is reached at approx. 4800 rpm.
Engine Data
The technical data is detailed below.
DESCRIPTION TYPE
Engine type/valves R6/4
Displacement (eff.) 2926 ccm
Stroke/bore 88.0/84.0 mm
Compression ratio 18 : 1
Firing order 1, 5, 3, 6, 2, 4
Engine weight 210 kg
Power to weight ratio 1.56 kg/kW
Total oil capacity (including
filter)
8.8 litres
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-3
Cylinder Block Components
The cylinder block components are described below:
Cylinder Block
The cylinders and crankcase are contained in the cylinder block, which is of single grey cast iron construction with
hollow beam structure. The cylinders are direct bored. Oil is supplied via lubrication jets for piston and gudgeon pin
lubrication and cooling.
Lubrication oil is distributed throughout the block via the main oil gallery to critical moving parts through channels
bored in the block which divert oil to the main bearings, and to the big-end bearings via holes machined into the
crankshaft.
A tapping at the front RH side of the cylinder block connects a pipe to the turbocharger by means of a banjo
connection. Oil under pressure from the oil pump provides lubrication for the turbocharger bearings.
Cylinder cooling is achieved by coolant circulating through chambers in the engine block casting.
NOTE: The water jacket does not have core plugs.
Two hollow metal dowels are used to locate the cylinder block to the cylinder head, one on each side at the front of
the unit. Two additional hollow metal dowels are used to locate the timing cover to the cylinder block.
A port is included at the rear right hand side of the cylinder block which connects to the turbocharger oil drain pipe to
return lubrication oil to the sump.
A plug sealing the lubrication cross-drilling gallery is located at the front right hand side of the cylinder block. Plugs
for the main lubrication gallery are included at the front and rear of the cylinder block.
Connecting Rods
The connecting rods are machined, H-sectioned steel forgings. The big-end bearing shells are plain split halves. The
upper half of the bearing shell is treated using the sputtering process (cathodic surface coating process) to improve
its resistance to wear.
The small-end of the connecting rod has a bushed solid eye which is free to move on the gudgeon pin. The small-end
bush is a hand-push transition fit.
ENGINE – TD6
12-1-4 DESCRIPTION AND OPERATION
Connecting Rod and Piston
Pistons
The six pistons are gravity die cast with graphite-compound coated aluminium alloy skirts. Although the piston is
similar to that fitted to the Td4 engine the lobe in the piston crown bowl is higher.
The combustion chamber is designed on a swirl chamber principle.
The swirl chamber partly contains the inlet air during the combustion process and helps provide turbulence for efficient
air/fuel mixture to promote complete combustion. This reduces fuel consumption, exhaust emission and smoke
produced at full load. The four recesses in the piston's crown also provide clearance for the valve heads.
The pistons are attached to the small-end of the connecting rods by fully floating gudgeon pins which are retained in
the piston by circlips.
The pistons incorporate an oil cooling channel for piston and gudgeon pin cooling, oil being supplied under pressure
from the piston lubrication jets.
Piston Rings
Each piston is fitted with two compression rings and an oil control ring. The top compression ring is located in a steel
insert ring carrier which helps to provide a minimal reaction to compression forces.
The top ring is a 10° chromium-plated keystone ring. The 2nd compression ring is a tapered compression ring and
the lower ring is a chromium-plated spring loaded bevelled ring.
Piston Lubrication Jets
The six lubrication jets (one for each cylinder) have a long hook-type nozzle and are fitted at the bottom right hand
side of each cylinder.
The jets provide lubrication to the cylinder walls, and to the piston underskirt for cooling the pistons and lubricating
the gudgeon pins and small-end bearings. The input port to each lubrication jet mates with a port provided in each
mounting position, tapped at the underside of the cylinder block from a main gallery on the RH side of the block.
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-5
Integrated Oil Cooler and Filter Assembly
1 Sealing gasket
2 Filter housing
3 Filter element
4 O-ring seal – cap
5 O-ring seal (2 off)
6 Filter cap
7 Heat exchanger
8 Heat exchanger to filter housing attachment
bolt (Torx –3 off)
9 Heat exchanger to filter housing gasket
10 Oil pressure switch
11 Filter housing to engine block attachment bolts
– 3 off
The combined engine oil cooler and filter assembly, mounted to the left side of the engine block, is connected to the
vehicle cooling and lubrication systems. The disposable paper filter element is replaced by unscrewing the cover from
the filter housing.
The oil filter housing has an integral thermostatic valve which controls the amount of oil flowing through the oil cooler,
dependent on the oil temperature.
Oil from the cylinder block passes through the oil filter housing and partial flow is directed through the oil cooler before
it is returned to the cylinder block. The coolant for the heat exchanger is supplied directly from the crankcase.
The oil pressure switch, operating a warning lamp in the instrument pack, is fitted to the oil filter housing.
Oil Pressure Switch
The oil pressure switch is located in a port in the oil filter housing. If the oil pressure drops below a given value the
switch operates the warning lamp in the instrument pack
ENGINE – TD6
12-1-6 DESCRIPTION AND OPERATION
High Pressure Fuel Pump
The high pressure fuel pump supplies fuel to the fuel rail and is fixed to a flange on the front LH side of the cylinder
block. The pump is a 3 radial piston type controlled by the EDC engine management system and chain driven from
the crankshaft at 0.75 times engine speed.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor is mounted on the rear LH side of the cylinder block. The sensor is an inductive
type which acts on a reluctor on the flywheel.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
Crankshaft and Sump Components
The crankshaft and sump and oil pump components are described below:
Crankshaft
Crankshaft Drive
Arrow denotes front of engine.
1 No 1 Piston
2 No 6 Piston
3 Incremental wheel
The crankshaft is manufactured from high tensile steel. The bearing surfaces and radii are inductively hardened for
toughness and fatigue resistance. It is supported on 7 main bearings with a flanged thrust bearing located between
No 5 and No 6 cylinders. Dynamic balancing is achieved by the use of twelve balance weights.
Cross-drillings in the crankshaft between the adjoining main and big-end bearings are used to divert the lubrication
oil to the big-end bearings.
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-7
Crankshafts are available in three sizes:
l Standard
l Undersize 1
l Undersize 2.
Colour coding identifies the size of the journal.
At the front of the crankshaft is a four-hole threaded connection, used to attach the axially vibration damper and
cooling fan. The engine RPM signal is taken from the reluctor “target” attached to the crankshaft.
The crankshaft oil seals are manufactured from PTFE.
Main Bearings
The main crankshaft bearing shells have oil grooves and a drilling in the upper bearing shell, to provide oil via the
crankshaft drillings to the connecting rod big-end bearings.
Sump
The one-piece aluminium die-cast sump, with an integral tunnel for the differential drive shaft, is sealed to the lower
crankcase extension using a rubber metal-backed gasket. The sump is fixed to the lower crankcase extension using
25 bolts. An oil deflector plate is attached to the crankcase reinforcing shell above the sump.
Oil Pump
The oil pump assembly is bolted to the bottom of the cylinder block and is located in front of the engine block stiffener
plate. The pump is an internal gear-type with sintered rotors and is driven through a chain and sprocket system from
the crankshaft.
A pressure relief valve is included at the outlet side of the oil pump to control oil pressure at high engine speeds by
recirculating oil through the relief valve back around the pump to the inlet. The relief valve and spring is a plunger type;
when oil pressure is great enough to lift the plunger, oil is allowed to escape past the plunger to relieve pressure and
prevent any further rise in pressure.
Oil is delivered to the pump from the pick-up pipe, and the outlet side of the oil pump delivers pressurised oil flow to
the engine block main oil delivery gallery.
Flywheel
Located between the engine and transmission the flywheel is of sheet metal laminated construction.
ENGINE – TD6
12-1-8 DESCRIPTION AND OPERATION
Camshaft Timing Components
Chain Drive
1 Camshaft
2 Guide rail
3 Crankshaft
4 Common rail high pressure pump
5 Oil pump
6 Tensioning rail
7 Chain tensioner
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-9
The camshaft timing components are described below:
Timing Case Cover
The timing chain cover is cast and machined aluminium alloy and is bolted to the cylinder block. Five bolts are used
to fix the upper flange of the timing cover to the cylinder head casting, and a further four bolts secure the front of the
sump to the timing cover. The bottom of the timing cover is located to the front face of the cylinder block by two metal
dowels.
The front of the crankshaft passes through a hole in the timing cover, and a replaceable beaded gasket is used to seal
the interface between the front of the crankshaft and the timing cover.
The ancillary components and belt pulley attachments are fitted to the front cover.
Chain Drive
Two timing chain drives are used. The timing chain between the crankshaft sprocket and the fuel injection pump
sprocket is a simplex type. The timing chain is contained between one fixed and one hydraulically adjustable
tensioning rail.
The chain drive from the fuel injection pump sprocket to the two camshaft sprockets is also a simplex type. The chain
runs between one fixed guide rail and a hydraulically adjustable tensioning rail to minimise chain flutter. An additional
plastic chain guide is located above the two camshaft sprockets.
The adjustable tensioning rails are of aluminium die casting construction with clip-fastened plastic slide linings. The
fixed guide rails are moulded plastic. The tensioner rails are attached to the front of the cylinder blocks using pivot
bolts which allow the tensioner rail to pivot about its axis.
The spring tensioner for both chains is provided from a single unit which contains two spring operated, hydraulically
damped plungers that operate on the tensioning rails at the slack side of each of the timing chains. Pressurised oil for
the adjuster is supplied through the back of the unit from an oil supply port in the front of the cylinder block. The lateral
movement in the tensioner arm causes the timing chain to tension and consequently, compensation for chain flutter
and timing chain wear is automatically controlled.
The timing chains are oil splash lubricated via the oil pump and chain tensioner. Oil spray is directed to the chain from
several oil supply ports in the front of the cylinder block and cylinder head.
An additional chain from the crankshaft sprocket connects to the oil pump sprocket for oil pump operation.
Cylinder Head Components
The cylinder head components are described below:
Cylinder Head
Although the Td6 is of an in-line configuration its cylinders are arranged into 2 sets of three. The forward set consists
of cylinders 1 to 3 and the rear bank consists of cylinders 4 to 6.
The cylinder head is of aluminium gravity die casting construction. The cylinder head is bolted to the cylinder block by
means of M12 cylinder head bolts arranged beneath each camshaft.
NOTE: The cylinder head bolts are not accessible with the camshafts fitted.
ENGINE – TD6
12-1-10 DESCRIPTION AND OPERATION
Inlet Port Configuration
1 Exhaust ports
2 Exhaust valves
3 Fuel injector
4 Inlet swirl port
5 Inlet valves
6 Inlet tangential port
7 Glow plug
The aluminium cylinder head houses the chain driven overhead camshafts, valve gear, fuel injectors and glow plugs.
The Td6 engine has a 4–valve arrangement, similar to the Td4. There are two exhaust ports, combined in the cylinder
head, a tangential inlet and a swirl inlet port. The common fuel injector rail is centrally mounted with the glow plug
fitted to the inlet side.
Coolant flow enters the head from the exhaust side and exits, between No 3 and No 4 cylinder, the inlet side to the
heater matrix and radiator. The Engine Coolant Temperature (ECT) sensor is screwed into an aperture at the rear LH
side of the cylinder head.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
+ COOLING SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
Cylinder Head Cover
The plastic moulded cylinder head cover is used to seal off the oil chamber in the cylinder head. It shields oil spray
from the camshaft and the chain drive gear, and acts as a housing for the valve gear.
An oil separator for the crankcase ventilation system is mounted at the top of the cover. This provides preliminary oil
separation by cyclone, and fine separation using an internal yarn wrap. The separator unit also contains a pressure
control valve.
The camshaft cover includes an integrated air filter housing which is de-coupled from the cylinder head to absorb and
minimise the transmission of engine noise. The camshaft cover also provides a mounting for the mass air-flow (MAF)
sensor.
Cylinder Head Gasket
The multi-layed steel cylinder head gasket has cylinder specific water flow cross-sections for uniform coolant flow.
There are three thicknesses of gasket available, selected according to the determined piston clearance. The thickness
of the gasket is identified by the number of identification holes, one hole being the thinnest and three holes being the
thickest.
1
6
M12 7769
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4
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-11
Vacuum Pump
The vacuum pump is located on a support bracket at the front RH side of the cylinder head and is driven from the
exhaust camshaft.
Camshafts
There are two camshafts, exhaust (right) and intake (left). Each camshaft is maintained in position by seven bearing
caps. Each bearing cap is fixed to the cylinder head by two bolts. The camshafts are made using the clear chill casting
process and are hollow cast. The cam lobes have a negative cam radius. The camshafts are driven from the
crankshaft using a simplex chain and sprocket arrangement.
Each camshaft has twelve machined lobes for operating the inlet and exhaust valves through lash adjusters and roller-
type finger levers.
Inlet and Exhaust Valves
Valve Gear Layout
The inlet and exhaust valves are identical and have ground, solid one-piece head and stems made from Nimonic alloy
material.
The valve springs are made from spring steel and are of the parallel single-coil type. The bottom end of each spring
rests on the flange of a spring retainer which has an integral valve stem seal. The top end of the spring is held in place
by a spring retainer which is held in position at the top end of the valve stem by split taper collets. The taper collets
have grooves on the internal bore that locate to grooves ground into the upper stems of the valves.
Valve seats and valve guides are an interference fit in the cylinder head.
M12 7768
ENGINE – TD6
12-1-12 DESCRIPTION AND OPERATION
Hydraulic Lash Adjusters and Roller Finger Rockers
The valves are operated through roller-type finger rockers and hydraulic lash adjusters, actuated by the camshaft
lobes. When the camshaft lobe presses down on the top of a finger rocker, roller mechanism, the respective valve is
forced down, opening the affected inlet or exhaust port. The use of this type of actuation method helps reduce friction
in the valve timing mechanism.
The body of the hydraulic lash adjusters contains a plunger and two chambers for oil feed and pressurised oil. The
pressurised oil is supplied to the lash adjusters via the main oil galleries in the cylinder head and through a hole in the
side of the lash adjuster body. The oil passes into a feed chamber in the lash adjuster and then through to a separate
pressure chamber via a one way ball valve.
Oil flow from the pressure chamber is determined by the amount of clearance between the lash adjuster outer body
and the centre plunger. Oil escapes up the side of the plunger every time the lash adjuster is operated, the downward
pressure on the plunger forcing a corresponding amount of oil in the lash adjuster body to be displaced. When the
downward pressure from the camshaft and finger rocker is removed (i.e. after the trailing flank of the camshaft lobe
has passed), oil pressure forces the lash adjuster's plunger up again. This pressure is not sufficient to effect the valve
operation, but eliminates the clearance between the finger rocker and top of the valve stem.
Electronic Fuel Injectors
There are six electronic fuel injectors (one for each cylinder), each located in the centre of a cylinder's four valves.
The electronic fuel injectors are supplied with fuel from the fuel rail and deliver finely atomised fuel directly into the
fuel chambers.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
Ancillary Components and Belt Drives
The ancillary components, which comprise the torsional vibration damper, alternator, A/C compressor, steering pump
and water pump, are driven by the engine crankshaft via the ancillary drive belts.
The belts, which are maintenance free poly-V type belts, are automatically pre-loaded by the tensioning rollers and
are routed over deflection pulleys in order to maintain sufficient adhesion about the drive wheels. This ensures slip-
free drive of the ancillary components.
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-13
Belt Drive
1 Water pump
2 Tensioning pulley
3 Power steering pump
4 Alternator pulley
5 Idler pulley
6 Torsional vibration damper
7 A/C compressor
Torsional Vibration Damper
The torsional vibration damper with decoupled belt pulley suppresses longitudinal vibration and reduces noise. It is
mounted to the forward end of the crankshaft with 4 central bolts torque loaded to 45 Nm.
Tensioning Pulley
The tensioning pulley or idler pulley is a spring-loaded element.
Lubrication
The lubrication system is a wet sump, pressure fed type. It lubricates the engine sliding surfaces, dissipates heat,
absorbs fuel combustion residue and seals off the gap between the cylinder and piston.
M12 7763A
2
6
2
1
3
4
7
5
ENGINE – TD6
12-1-14 DESCRIPTION AND OPERATION
Lubrication Circuit
1 Pressure supply to upper chain lubrication
2 Camshaft bearing
3 Runout stop – Hydraulic Valve Adjuster gallery
4 Hydraulic valve lash adjuster gallery (HVA)
5 Piston spray nozzle — hook-type nozzle
6 Cylinder block main oil gallery feed for
crankshaft bearings
7 Oil filter with oil cooler
8 Oil gallery after oil filter — main oil gallery
9 Oil intake pipe
10 Unfiltered oil duct
11 Oil pump
12 Pressure supply for upper chain lubrication
13 Pressure supply to Turbo-charger
14 Riser to cylinder head
15 Pressure supply to vacuum pump
Operation
Oil from the sump is drawn up through a fabricated metal pick-up pipe which contains a mesh to filter out any relatively
large pieces of material which could cause damage to the oil pump. The head of the pick-up is centrally immersed in
the sump oil which is delivered to the inlet side of the eccentric rotary pump.
The oil pump is driven from the crankshaft by a chain and sprocket system. Pressurised oil from the pump is passed
through a port in the bottom of the cylinder block and is directed up to the oil inlet port of the oil cooler and filter housing
via a port in the RH side of the cylinder block. The oil pump contains an oil pressure relief valve which opens to allow
oil to be recirculated back around the pump if the oil pressure increases to a high enough level.
9
11
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7
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14
M12 7764
13
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6
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-15
The inlet port of the oil cooler and filter housing has an integral non-return valve which allows flow into the filter, but
prevents unfiltered oil draining back out of the filter housing when oil pressure is reduced.
The oil passes through the oil filter element and out to the oil cooler. The percentage of oil flow passed through to the
oil cooler is dependent on a thermostatic by-pass valve which is integrated into the oil filter housing. An increase in
oil temperature causes the by-pass valve to open and allow a greater percentage of oil flow to be directed through the
oil cooler. The remainder of the oil flow from the outlet side of the filter element is directed to the outlet port of the oil
filter housing where it combines with the oil flow being returned from the oil cooler before being passed back into the
cylinder block.
An oil pressure switch is included in the outlet port of the oil filter housing to sense the oil pressure level before the oil
flow enters the main oil gallery in the engine block. A warning lamp in the instrument pack is switched on if the oil
pressure is detected to be too low.
+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
Oil entering the cylinder block main gallery passes through drillings to the crankshaft main bearings and cross drillings
in the crankshaft direct oil to the big-end bearings. An additional four drillings in the cylinder block supply oil at reduced
pressure to the lubrication jets for piston and cylinder cooling and gudgeon pin lubrication.
A cross channel from the LH main oil gallery crosses to the RH side of the cylinder block where there is an outlet port
which provides a pressurised oil supply to the turbocharger bearings via a banjo connection and external piping.
Riser channels at the front RH side and rear LH side of the cylinder block are used to channel oil to mating ports in
the cylinder head and provide a source for cylinder head lubrication and operating pressure for the lash adjusters.
Oil is fed through oil galleries at the LH and RH side of the engine and six cross channels from each gallery directs
oil to the camshaft bearings. Lubrication oil fed to the lash adjusters passes up through the lash adjuster's body to the
finger rockers for lubrication of the surfaces between the finger rockers and the camshaft lobes.
Tapered plugs seal the cylinder head oil galleries at the rear of the cylinder head, and an additional tapered plug is
included inside the cylinder head at the front of the RH gallery.
An additional riser channel from the cylinder block LH main oil gallery is used to supply lubrication to the timing chain
system through several outlet ports at the front of the cylinder block and cylinder head.
ENGINE – TD6
12-1-16 DESCRIPTION AND OPERATION
Engine Mounts
System Layout
1 Right hydraulic damper
2 Right engine mounting
3 Left engine mounting
4 Left hydraulic damper
5 Vacuum supply pipe
6 Engine mount damping control actuator
Two hydraulically dampened engine mounts are fitted between the engine support brackets and engine sub-frame to
reduce the level of transmitted engine vibration and noise.
The damping characteristics of the mounts are regulated by controlling the rate of hydraulic fluid transfer between two
internal chambers.
The system consists of two hydraulic mounts, with variable damping regulated by a vacuum, a control actuator,
electric and vacuum lines. The vacuum, controlled by the electrical control actuator, is supplied via a distributor in the
vacuum line between the vacuum pump and brake booster. The system is controlled by the EDC System.
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-17
Hydraulic Engine Mount
1 Vacuum connection
2 Bellows
3 Nozzle
4 Annular channel
5 Diaphragm
6 Upper hydraulic chamber
7 Orifice
8 Upper nozzle plate
9 Nozzle
10 Lower nozzle plate
11 Lower hydraulic chamber
12 Support cup
13 Spring
14 Channel
M12 7766
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11
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ENGINE – TD6
12-1-18 DESCRIPTION AND OPERATION
Operation
By applying a vacuum, the Engine Control Module (ECM) controls the engine damping mounting in two stages:
“Hard” Engine Mount
In the basic setting no vacuum is applied to the hydraulic mount. The spring (13) acts on the support cup (12) to close
the U-bellows against the upper nozzle plate (8). Hydraulic fluid flows from the upper hydraulic chamber (6) via the
nozzle (9), the annular channel (4) and via nozzle (3) into the lower hydraulic chamber (11).
The annular channel extends over approximately 300 degrees. Due to the length of the annular channel and the small
nozzle orifice hydraulic oil flows between the upper and lower hydraulic chamber only in the case of vibrations up to
the natural frequency of the engine (approximately. 10 Hz), thus producing a vibration absorber effect.
At higher frequencies, the equalisation between the hydraulic chambers is inhibited by the length of the annular
channel and the small nozzle orifices. In practical terms, equalisation between the upper and lower hydraulic chamber
does not take place.
Diaphragms (5) are fitted in the holes (7) of the nozzle plates in order to achieve good acoustic characteristics at high
frequencies with small amplitude.
"Soft" Engine Mount
At idling speed and in the speed range close to idling, the spring (13) is pulled down by applying vacuum at vacuum
connection (1). The channel (14) in the centre of the upper nozzle plate now acts as a bypass between the upper and
lower hydraulic chamber. This allows the hydraulic fluid to flow unrestricted between the upper and lower chambers.
The increase in the fluid flow rate softens the damping action of the hydraulic mount, reducing the dynamic rigidity of
the engine mount.
EDC Parameters
The ECM controls the engine mounts based on the following parameters:
Switching Value
Engine Speed 900 RPM
Vehicle speed 60 km/h (36 MPH)
ENGINE – TD6
DESCRIPTION AND OPERATION 12-1-19
Vacuum Supply
Distributor
The vacuum necessary for activating the engine mounts is obtained via a distributor located in the vacuum line
between the vacuum pump and brake booster.
For this purpose, the vacuum line of the damping-controlled hydraulic mount is connected to the long outlet of the
distributor.
The vacuum varies within the pressure range from 0.5 to 0.9 bar. It is switched by means of a damping control
actuator.
ENGINE – TD6
12-1-20 DESCRIPTION AND OPERATION
ENGINE - V8
DESCRIPTION AND OPERATION 12-2-1
ENGINE - V8DESCRIPTION AND OPERATION
V8 – External View
M12 7816
ENGINE - V8
12-2-2 DESCRIPTION AND OPERATION
Description
General
The V8 petrol engine is a 4.4 litre, eight cylinder water cooled engine having two banks of four cylinders, arranged at
90 degrees to each other, with four valves per cylinder. The engine emissions comply with ECD3 (European
Commission Directive) and NAS LEV 2 legislative requirements. The engine comprises five main castings - two
cylinder heads, cylinder block, timing cover and the oil sump, all of which are manufactured from aluminium alloy.
Plastic rocker covers are fitted to the cylinder heads and, between the cylinder heads, is a plastic manifold intake
assembly. A plastic moulded acoustic cover is fitted over the upper engine to reduce engine generated noise.
The engine is supported, between cast mounting brackets and the front subframe, on two self-contained hydraulically
damped mounts.
Technical Features
The technical features include:
l Four valves per cylinder
l Single plenum chamber
l Variable Camshaft Control (VCC) system
l Double roller timing chain
l Hydraulic Valve Adjusters (HVA)
l Water Cooled Oil Cooler.
Engine Data
The technical data is detailed below
The cylinders are numbered as follows:
NOTE: Cylinders 4 and 8 are at the rear of the engine
Cylinder Block Components
The cylinder block components are described below:
Engine type 90° V
Cylinders 8
Displacement 4398 ccm
Stroke/bore 82.7/92.0 mm
Maximum Power 210 kW (285 PS; 282 bhp) @ 5400
rev/min
Maximum Torque 440 Nm (324 lbf.ft) @ 3600 rev/min
Compression ratio 10: 1
Firing order 1–5–4–8–6–3–7–2
Left bank 5 — 8
Right bank 1 — 4
ENGINE - V8
DESCRIPTION AND OPERATION 12-2-3
Crankcase
The crankcase is made from Alusil for markets where the fuel contains a high sulphur content. The cylinder barrels
have a nickel dispersion coating (Nikasil), and are finished by polishing only.
An adaptor plate for the feed and return flexible pipes to the oil filter assembly is fitted to the left side of the crankcase.
A water drain plug is located at the lower LH rear corner to drain coolant from the crankcase.
Crankcase Ventilation
The crankcase ventilation system is pressure regulated by a valve mounted at the rear of the inlet manifold. Vacuum
supply ports are incorporated on the valve for the power brake booster and the fuel pressure regulator
The pressure regulating vent valve varies the vacuum applied to the crankcase depending on engine load. The valve
is balanced between spring pressure and the amount of manifold vacuum. At idle when the vacuum is high, the valve
closes down and only allows a small amount of blow-by vapours to pass into the manifold. At part to full load
conditions, the spring opens the valve and additional blow-by gasses flow into the manifold. An additional tube leads
the blow-by gasses through the manifold and up to the mixing plate.
The crankcase ventilation system is completely sealed. Hose clamps are used at all connections to ensure that the
system does not contain any leaks.
The crankcase ventilation system uses a cyclone separator to purge the blow-by gasses of any oil vapours. The oil
vapours condense in the separator and drain back into the sump.
ENGINE - V8
12-2-4 DESCRIPTION AND OPERATION
Crankcase Ventilation System
1 Oil separator
2 Breather hose, oil separator to vent valve
3 Breather hose, LH camshaft cover to oil
separator
4 Inlet manifold cover and vent valve
5 Inlet manifold
6 Oil drain pipe assembly
7 Inlet manifold vacuum pipe
8 Mixing plate
9 Vent valve spring
10 Vent valve diaphragm
11 Atmospheric vent
12 Blow-by gasses
M12 7839A
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5
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ENGINE - V8
DESCRIPTION AND OPERATION 12-2-5
Crankshaft
The crankshaft is manufactured from forged steel with five main bearings and the thrust bearing on number five
bearing. Six counterweights fitted. These are positioned in harmony with the ignition firing order to ensure smooth
running.
The crank pins are offset by 90° and hollow bored to reduce weight.
There are four sizes of crankshaft available, standard and three undersizes.
Colour coding identifies the size of the journal.
The main bearing caps have a unique four bolt fixing for additional strength, and threaded protective bushes which
are torqued before the collar screws are installed.
NOTE: For information on colour coding and journal sizes, refer to the General Data section of the workshop manual.
At the front of the crankshaft, incorporated in the auxiliary belt pulley is a torsional vibration damper. Fitted behind the
damper, to the crankshaft, is the drive sprocket for the camshaft and oil pump.
Torsional Vibration Damper
The torsional vibration damper with decoupled belt pulley suppresses longitudinal vibration and reduces noise. It is
mounted at front of the crankshaft with 4 bolts torque loaded to 45 Nm.
ENGINE - V8
12-2-6 DESCRIPTION AND OPERATION
Bearing Shells
The upper bearing shells have oil grooves and a drilling to provide oil, via drillings in the crankshaft to the crankshaft
main bearings and the connecting rod journals
Flywheel
1 Flywheel
2 Torque converter attachment holes
3 Reluctor ring
4 Starter motor ring gear
The single piece steel flywheel is bolted to the rear of the crankshaft with nine bolts. The torque converter is bolted to
the rear of the flywheel with four bolts.
Attached to the flywheel is the reluctor ring for the crankshaft position sensor and the starter motor ring gear.
ENGINE - V8
DESCRIPTION AND OPERATION 12-2-7
Connecting Rods
The connecting rods are sintered type, one piece forged rods which feature a fracture-split at the big-end between the
connecting rod and the bearing cap. The mating surface of the rod and bearing cap form a rough surface (interference
fit) that eliminates the need for centering sleeves. Each matched rod and bearing cap pair is stamped with a pairing
code.
All of the rods are of one weight class and conform to the double bearing classification, red or blue. One red and one
blue bearing shell are fitted to each connecting rod. The red shell is fitted to the bearing cap.
Pistons
The pistons are of a short skirt design and “iron coated” for use with the Alusil block. Each piston has a flat crown
surface with a front facing arrow for installation direction. The relevant cylinder bank number is engraved into the
piston crown.
Each piston is fitted with two compression rings and an oil control ring.
There are no thermal control strips in the pistons. The pistons are cooled with specific spray jets, mounted in the
crankcase.
M12 7806
ENGINE - V8
12-2-8 DESCRIPTION AND OPERATION
Piston Lubrication Jets
Hook-type nozzles are connected directly into an oil gallery in the crankcase and secured by two screws.
The jets provide lubrication to the cylinder walls, and to the piston underskirt for cooling the pistons and lubricating
the gudgeon pins and small-end bearings.
M12 7843
ENGINE - V8
DESCRIPTION AND OPERATION 12-2-9
Timing Case Covers
Separate timing case covers are bolted to the two cylinder heads and the crankcase.
The upper timing case covers have ports for the VCC solenoid valves and Camshaft Position (CMP) sensors. The
lower cover has an integral mounting for the alternator which acts as a water jacket. A drain plug and sealing ring is
fitted to the bottom of the mounting.
Rubber pre-formed gaskets form seals between the cylinder heads and crankcase and respective timing case covers.
ENGINE - V8
12-2-10 DESCRIPTION AND OPERATION
Sump
The two-piece aluminium die-cast sump, with an integral tunnel for the differential drive shaft, is sealed to the lower
crankcase extension using a rubber metal-backed gasket. The sump is fixed to the lower crankcase extension using
25 bolts. An oil deflector plate is attached to the crankcase reinforcing shell above the sump. The sump incorporates
a drain plug and a dip-stick guide tube.
Oil Pump
The oil pump housing and cover is manufactured from cast aluminium. The gear type oil pump is driven via the
crankshaft.
The oil pump is located in the sump and is attached to Nos 1 and 2 main bearing caps. The rotor-type pump produces
a regulated pressure of approximately 4.5 bar.
A metal suction pipe obtains oil from the sump.
ENGINE - V8
DESCRIPTION AND OPERATION 12-2-11
Oil Filter Assembly
The oil filter assembly, with a replaceable element, is mounted remote to the engine. It is attached to a mounting
bracket fitted to the left of the radiator and the filter is mounted on two rubber mounts to reduce vibration.
Two re-inforced flexible hoses, feed and return, are fitted between the filter assembly and the crankcase mounted
adaptor plate. The hose connections are of the push fit type and sealed with an “O” ring seal. The filter hose
connections are secured by a locking plate bolted to the filter body. The sump hose connections are secured to the
crankcase adaptor with a securing bracket. This bracket is attached with a stud and nut.
A by-pass valve is located internally in the lower end of the filter body. This allows the oil to by-pass the filter if the
filter element becomes blocked
A second valve is screwed into the filter body. It is connected to a rigid pipe on the sump by a flexible hose secured
by two hose clips. The rigid pipe has a banjo fitting on the sump connection. When the filter is removed, the valve
opens allowing oil in the housing to drain to the sump.
The oil pressure switch screws into the base of the filter body.
ENGINE - V8
12-2-12 DESCRIPTION AND OPERATION
Cylinder Head Components
The cylinder head components are described in the following paragraphs.
Cylinder Head Cover
The cylinder head cover is manufactured from magnesium alloy and is secured to the cylinder head with 11 threaded
spacers with rubber seals. The right hand cover incorporates an oil filler cap.
The cylinder head cover also provides mounting for the coils. The coils are protected by a plastic cover, sealed with
a rubber gasket. The cover is retained with two bolts which are covered with protective caps.
NOTE: Damage to the magnesium cover may cause corrosion.
Cylinder Heads
The cross flow cylinder heads are made of die-cast aluminium and feature:
l Centrally located spark plugs
l Four valves per cylinder
l Two camshafts
l Bucket tappets with hydraulic valve clearance adjusters.
The combustion chambers are machined into the heads, thus ensuring more uniform “matched” combustion
chambers and compression pressures.
Bolted to the front end of the cylinder head are the oil distribution flanges. The flanges provide a mounting for the VCC
solenoids and the advance-retard ports from the solenoids to the intake camshafts.
ENGINE - V8
DESCRIPTION AND OPERATION 12-2-13
The cylinder heads for each bank are different lengths due to the offset of the cylinder rows (cylinder bank 1–4 is
shorter).
NOTE: The cylinder head gasket part numbers are different for the two cylinder banks.
The cylinder head is machineable to a limit of 0.3 mm. A repair cylinder head gasket is available and is identified by
a small hole beside the 4th and 8th cylinder apertures.
Camshafts
Two solid cast iron camshafts are used for each cylinder head. The cams run in five machined bearing surfaces with
numbered caps for identification.
The camshafts are also marked for identification and incorporate hexagonal machined blocks for timing the cams
during installation.
For installation and servicing, the camshafts are held in position with locking pins. These pins are inserted into the
front camshaft bearing caps on both cylinder heads.
Valves
The intake and exhaust valves are arranged in a “V” pattern. The valves use single, conical, coil bound shaped valve
springs and Hydraulic Valve Adjustment (HVA) tappets and each comprises the following components:
l Valve x 1 (inlet or exhaust)
l Valve stem seal x 1
l Valve spring x 1
l Valve spring seat x 1
l Valve spring cap x 1
l Valve collets x 2
l Tappet x 1.
Hydraulic Valve Adjustment Tappets
Bucket type hydraulic tappets are used for adjusting the valve clearance. The buckets are self-breathing with a carbon
nitride finished cam contact surface.
Primary drive
Primary drive is provided by a single roller chain from the crankshaft to the two rubber coated cam gears. The train is
guided by a centrally positioned V-shaped aluminium deflector rail, a straight rail on cylinder bank 5 to 8 and a curved
tensioner rail on cylinder bank 1 to 4.
Timing chain adjustment is carried out with a hydraulic tensioner mounted on the upper case for cylinders 1 to 4
Secondary Drive
Secondary drive is from the intake camshaft to the exhaust camshaft by a single roller chain. Chain tension is
maintained by a hydraulic, spring assisted tensioner that incorporates an oil spray jet.
The oil supply for the chain tensioner also supplies the VCC hydraulic units through a pressure control valve.
ENGINE - V8
12-2-14 DESCRIPTION AND OPERATION
Ancillary Components and Belt Drive
The ancillary components, the torsional vibration damper, alternator, A/C compressor, steering pump and water
pump, are driven by the engine crankshaft by the aid of the ancillary drive belts. The A/C compressor is driven by a
separate belt.
The belts, which are maintenance free poly-vee type belts, are automatically pre-loaded by two tensioning spring pots
and are routed over deflection pulleys in order to maintain sufficient adhesion about the ancillary pulleys. This ensures
slip-free drive of the ancillary components.
Belt Drive
1 Coolant pump
2 Idler pulley
3 Alternator
4 Power assisted steering pump
5 Tensioner pulley
6 Crankshaft pulley
7 Tensioner pulley
8 A/C compressor
Air Intake System
The inlet manifold is a light weight, one piece plastic moulding. Fuel is supplied by a single fuel rail and regulated by
a single pressure regulator mounted on the end of the rail. The manifold is acoustically decoupled from the cylinder
heads to reduce noise and vibrations.
The throttle plate has two wedges screwed directly to it, these provide a curved zone for smoother throttle response
during idle, off-idle transition.
The combined output of the mixing plate ensures that the gasses and vapours are evenly distributed among all the
cylinders, which can improve idle quality.
M12 7815A
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ENGINE - V8
DESCRIPTION AND OPERATION 12-2-15
Lubrication
The lubrication system is a wet sump, pressure fed type. It lubricates the engine sliding surfaces, dissipates heat and
absorbs fuel combustion residue.
Operation
Oil from the sump is drawn up through a fabricated metal pick-up pipe which contains a mesh to filter out any relatively
large particles of material which could cause damage to the oil pump. The head of the pick-up is centrally immersed
in the sump oil which is delivered to the rotor pump.
Variable Camshaft Control (VCC)
The V8 engine uses a VCC (Variable Camshaft Control) system for valve timing on the intake camshaft. While the
engine is running the inlet camshafts are continuously adjusted to their optimum position.
Both camshafts are simultaneously adjusted to a maximum of 20° of the crankshaft rotational axis. This equates to a
maximum span of 40° crankshaft rotation.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, VCC System.
Cylinder Bank Components
Each cylinder bank contains the following:
l Cylinder head with oil ports for the VCC system
l Control solenoid valve
l VCC Transmission and sprockets
l Oil distribution flanges
l Oil check valve
l Camshaft position impulse wheels
l Camshaft position sensors.
Control Solenoid Valve
The control solenoid valve is fitted with an integral non-return valve and has four ports:
1 Input supply port — engine oil pressure
2 Output retard port — to rear of piston/helical gear (retarded camshaft position)
3 Output advance port — to rear of piston/helical gear (advanced camshaft position)
4 Vent — released oil pressure.
The non-return valve is fitted to the rear of the solenoid valve in the cylinder head oil gallery. The non-return valve
maintains an oil supply in the VCC transmission and oil circuits after the engine is switched off. This prevents piston
movement when the engine is restarted.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, VCC System.
VCC Transmission and Sprockets
The primary and secondary timing chain sprockets are integrated with the self-contained VCC transmission.
The controlled adjustment of the camshaft occurs inside the “transmission”. Controlled oil pressure moves the piston
axially.
The helical gear cut of the piston acts on the helical gears on the inside surface of the transmission and rotates the
camshaft to the specific advanced or retarded angle position.
Three electrical pin contacts are located on the front surface to verify the default maximum retard position using an
ohmmeter. This is required during assembly and adjustment.
Oil Distribution Flanges
The oil distribution flanges are bolted to the front surface of each cylinder head. They provide a mounting location for
the VCC solenoids as well as the advance-retard oil ports from the solenoids to the intake camshafts.
Camshafts
Each intake camshaft has two oil ports separated by three sealing rings on their forward ends. The ports direct
pressurized oil from the oil distribution flange to the inner workings of the VCC transmission. Each camshaft has left-
hand threaded bores in their centres for the attachment of the timing chain sprockets on the exhaust cams and the
VCC transmissions for each intake camshaft.
ENGINE - V8
12-2-16 DESCRIPTION AND OPERATION
Camshaft Position Impulse Wheels
The camshaft position impulse wheels provide camshaft position status to the engine control module via the camshaft
position sensors. The asymmetrical placement of the sensor wheel pulse plates provides the engine control module
with cylinder specific position ID in conjunction with crankshaft position.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
Camshaft Position Sensors
There are two CMP position sensors which are located on the upper timing case covers. The camshaft position
sensors monitor the position of the camshafts to establish ignition timing order, fuel injection triggering and for
accurate Variable Camshaft Control (VCC) camshaft advance-retard timing feedback. The camshaft position sensor
is a Hall-effect sensor which switches a battery fed supply on and off. The supply is switched when the teeth machined
onto the camshaft gear pass by the tip of the sensor. The four teeth are of differing shapes, so the ECM can determine
the exact position of the camshaft at any time.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-1
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ENGINE MANAGEMENT SYSTEM – Td6DESCRIPTION AND OPERATION
ENGINE MANAGEMENT SYSTEM – TD6
18-1-2 DESCRIPTION AND OPERATION
Engine Management Component
Location – Sheet 1 of 2
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-3
1 Exhaust Gas Recirculation (EGR) modulator
2 Boost pressure sensor
3 Engine Coolant Temperature (ECT) sensor
4 Engine mount damping control actuator
5 Anti-lock Brake System (ABS) ECU
6 Low Pressure (LP) sensor
7 Fuel filter
8 High Pressure (HP) fuel pump
9 Instrument pack
10 Exhaust Gas Recirculation (EGR) valve
11 Diagnostic socket
12 Accelerator Pedal Position (APP) sensor
13 Camshaft Position (CMP) sensor
14 Glow plug relay
15 Electronic Automatic Transmission (EAT) ECU
16 Environmental box (E-box)
ENGINE MANAGEMENT SYSTEM – TD6
18-1-4 DESCRIPTION AND OPERATION
Engine Management Component
Location – Sheet 2 of 2
1 Engine control Module (ECM)
2 Fuel rail pressure sensor
3 Crankshaft Position (CKP) sensor
4 Boost control solenoid valve
5 Fuel temperature sensor
6 Glow plugs
7 Oil pressure switch
8 Fuel rail pressure control valve
9 Fuel injectors
10 Mass Air Flow/Inlet Air Temperature (MAF/IAT)
sensor
11 Main relay
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-5
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ENGINE MANAGEMENT SYSTEM – TD6
18-1-6 DESCRIPTION AND OPERATION
Engine Management Control Diagram –
Sheet 1 of 2
A = Hardwired connection; D = CAN bus
M18 0774B
A
1
D
23 4
56 7
89
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-7
1 Glow plugs
2 Fusible link 100A (Glow plug relay supply)
3 Fusible link 100A (Main relay supply)
4 Fuse 30A (Ignition switch supply)
5 Glow plug relay
6 Main relay
7 Ignition switch
8 Fuse 30A
9 Fuse 5A
10 Fuel pump relay
11 Alternator
12 Fuel temperature sensor
13 Fuel rail pressure sensor
14 Boost control solenoid valve
15 Anti-lock Brake System (ABS) ECU
16 LP Fuel sensor
17 Accelerator Pedal Position (APP) sensor
18 Camshaft Position (CMP) sensor
19 Electronic Automatic Transmission (EAT) ECU
20 Mass Air Flow/Inlet Air Temperature (MAF/IAT)
sensor
21 Engine mount damping control actuator
22 Boost pressure sensor
23 Fuel pressure control valve
24 Exhaust Gas Recirculation (EGR) modulator
25 Fuse 30A (engine compartment fusebox)
26 Engine Control Module (ECM)
ENGINE MANAGEMENT SYSTEM – TD6
18-1-8 DESCRIPTION AND OPERATION
Engine Management Control Diagram –
Sheet 2 of 2
A = Hardwired connection; D = CAN bus; J = Diagnostic ISO9141 K Line
M18 0824
A
D
1111 11
2
3
4
5
6
8
910
11
12
13
14
7
J
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-9
1 Fuel injectors
2 Instrument pack
3 Engine oil pressure switch
4 Crankshaft Position (CKP) sensor
5 Electric engine/air conditioning cooling fan
6 Immobilisation ECU
7 Automatic Temperature Control (ATC) ECU
8 Engine Coolant Temperature (ECT) sensor
9 Rotary coupler
10 Cruise control switches
11 Diagnostic socket
12 Brake switch
13 Starter motor
14 Engine Control Module (ECM)
ENGINE MANAGEMENT SYSTEM – TD6
18-1-10 DESCRIPTION AND OPERATION
Description
General
The Td6 engine has an Electronic Diesel Control (EDC) engine management system. The system is controlled by an
Engine Control Module (ECM) and is able to monitor, adapt and precisely control the fuel injection. The ECM uses
multiple sensor inputs and precision control of actuators to achieve optimum performance during all driving conditions.
The ECM controls fuel delivery to all six cylinders via a Common Rail (CR) injection system. The CR system uses a
fuel rail to accumulate highly pressurised fuel and feed the six, electronically controlled injectors. The fuel rail is
located in close proximity to the injectors, which assists in maintaining full system pressure at each injector at all times.
The ECM uses the drive by wire principle for acceleration control. There are no control cables or physical connections
between the accelerator pedal and the engine. Accelerator pedal demand is communicated to the ECM by two
potentiometers located in a throttle position sensor. The ECM uses the two signals to determine the position, rate of
movement and direction of movement of the pedal. The ECM then uses this data, along with other engine information
from other sensors, to achieve the optimum engine response.
The ECM also controls the Exhaust Gas Recirculation (EGR) system which is fitted to reduce the formation of oxides
of nitrogen (NO
x
). This group of gases is formed in the combustion chamber under conditions of high temperature and
high pressure. It is not desirable to reduce the compression ratio, so the ECM reduces the combustion temperature
by introducing a controlled volume of inert gas into the cylinders on the induction stroke.
The inert gas used is exhaust gas, which is freely available. It is directed from the exhaust manifold, via a control valve,
into the intake manifold. The flow of gas is monitored by the ECM using a Mass Air Flow (MAF) sensor. The EGR
system is not required until the engine is hot, and is turned off during engine idling and wide open 'throttle' to preserve
smooth operation and driveability.
The ECM processes information from the following input sources:
l Brake switch
l Crankshaft Position (CKP) sensor
l Camshaft Position (CMP) sensor
l Anti-lock Brake System (ABS) ECU
l Engine Coolant Temperature (ECT) sensor
l Boost Pressure (BP) sensor
l Low side fuel pressure sensor
l Accelerator Pedal Position (APP) sensor
l Mass Air Flow/Intake Air Temperature (MAF/IAT) sensor
l Fuel rail pressure sensor
l Controller Area Network (CAN)
l Glow plug relay
l Immobilisation ECU.
The ECM outputs controlling signals to the following sensors and actuator:
l Fuel injector solenoids
l Boost control solenoid valve
l Exhaust Gas Recirculation (EGR) actuator
l Engine mount damping control actuator
l Glow plug relay
l Rail pressure control valve
l Electric cooling fan control
l Automatic Temperature Control (ATC) ECU.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-11
Engine Control Module (ECM)
1 Glow plug relay
2 Engine compartment fusebox
3 Circulation fan
4 Main relay
5 ECM
6 EAT ECU
The ECM has a steel casing to provide protection from electromagnetic radiation, and is located in the Environmental
box (E-box). The ECM connected to the vehicle harnesses via 5 connectors.
The ECM contains data processors and memory microchips. The output signals to the actuators are in the form of
ground paths provided by driver circuits within the ECM. The ECM driver circuits produce heat during normal
operation and dissipate this heat via the casing. The fan in the E-box assists with the cooling process by maintaining
a constant temperature with the E-box. The fan is controlled by a thermostatic switch located in the E-box. The E-box
has pipe connections to the vehicle interior and receives additional cooled air via the A/C system.
Some sensors receive a regulated voltage supplied by the ECM. This avoids incorrect signals caused by voltage drop
during cranking.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-12 DESCRIPTION AND OPERATION
The ECM performs self diagnostic routines and stores fault codes in its memory. These fault codes and diagnostics
can be accessed using TestBook/T4. If the ECM is to be replaced, the new ECM is supplied 'blank' and must be
configured to the vehicle using TestBook/T4. When the ECM is fitted, it must also be synchronised to the
immobilisation ECU using TestBook/T4. ECM's cannot be 'swopped' between vehicles.
The ECM is connected to the engine sensors which allow it to monitor the engine operating conditions. The ECM
processes these signals and decides the actions necessary to maintain optimum engine performance in terms of
driveability, fuel efficiency and exhaust emissions. The memory of the ECM is programmed with instructions for how
to control the engine, this known as the strategy. The memory also contains data in the form of maps which the ECM
uses as a basis for fuelling and emission control. By comparing the information from the sensors to the to the data in
the maps, the ECM is able to calculate the various output requirements. The ECM contains an adaptive strategy which
updates the system when components vary due to production tolerances or ageing.
The ECM receives a vehicle speed signal on a CAN bus connection from the ABS ECU. Vehicle speed is an important
input to the ECM strategies. The ABS ECU derives the speed signal from the ABS wheel speed sensors. The
frequency of this signal changes according to road speed. The ECM uses this signal to determine the following:
l How much to reduce engine torque during gear changes
l When to permit cruise control operation
l To control the operation of the cruise control
l Implementation of the idle strategy when the vehicle is stationary.
Engine Immobilisation
The immobilisation ECU receives information from related systems on the vehicle and passes a coded signal to the
ECM to allow starting if all starting parameters have been met. The information is decoded by the ECM which will
allow the engine to run if the information is correct.
The information is on a rolling code system and both the immobilisation ECU and the ECM will require synchronisation
if either component is renewed.
The immobilisation ECU also protects the starter motor from inadvertent operation. The immobilisation ECU receives
an engine speed signal from the ECM via the instrument pack. When the engine speed exceeds a predetermined
value, the immobilisation ECU prevents operation of the starter motor via an integral starter disable relay.
+ SECURITY, DESCRIPTION AND OPERATION, Description.
Diagnostic Self-Test
The ECM performs a self test routine every time the ignition is switched to position II. The ECM constantly monitors
the system while the ignition is in this position. Any faults found are stored in a non-volatile fault memory.
The fault memory contents can be read using TestBook/T4 (See Diagnostics below). TestBook/T4 also allows for the
testing of certain functions and the activation of actuators.
When a fault is detected, the component in question is tagged as defective. The tag is initially regarded as provisional
and is not changed to a confirmed status until a certain period of time has elapsed. When the fault is changed to
confirmed, the ECM adopts the default value for that function, if one is available.
Once the fault is classed as confirmed, a fault memory entry is generated. This entry is accompanied by the current
mileage and the environmental conditions at the time of the fault occurrence. The fault entry is stored in the ECM
EEPROM. If the fault is engine management system related, the ECM may illuminate the MIL in the instrument pack
to notify the driver of the fault condition.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-13
ECM Harness Connector C0331 Pin Details
ECM Harness Connector C0332 Pin Details
Pin No. Description Input/Output
1 Alternator warning lamp Output
2 Engine cranking signal Output
3 Not used –
4 Cooling fan control unit Output
5 and 6 Not used –
7 APP sensor 1 ground –
8 APP sensor 1 signal Input
9 APP sensor 1 supply Output
10 Fuel pump relay Output
11 Oil pressure signal Output
12 APP sensor 2 ground –
13 APP sensor 2 signal Input
14 APP sensor 2 supply Output
15 and 16 Not used –
17 Diagnostic socket ground –
18 Not used –
19 Reverse gear signal Output
20 Not used –
21 LCM
22 Road speed signal Input
23 Not used –
24 Brake pedal switch Input
25 Not used –
26 Ignition power supply Input
27 Steering wheel cruise control switches Input
28 Brake pedal switch –
29 A/C compressor clutch disengage signal Output
30 and 31 Not used –
32 Diagnostic ISO 9141 K line bus Input/Output
33 Immobilisation signal Input/Output
36 CAN bus high (connection with main bus system) Input/Output
37 CAN bus low (connection with main bus system) Input/Output
38 to 40 Not used –
Pin No. Description Input/Output
1 Feed to fuel injectors 4, 5 and 6 Output
2 Not used –
3 Ground for fuel injector 6 –
4 Feed to fuel injectors 1, 2 and 3 Output
5 Ground for fuel injector 1 –
6 Ground for fuel injector 4 –
7 Ground for fuel injector 2 –
8 Ground for fuel injector 3 –
9 Ground for fuel injector 5 –
ENGINE MANAGEMENT SYSTEM – TD6
18-1-14 DESCRIPTION AND OPERATION
ECM Harness Connector C0603 Pin Details
ECM Harness Connector C0604 Pin Details
ECM Harness Connector C0606 Pin Details
Pin No. Description Input/Output
1 Power supply from main relay Input
2 and 3 Not used –
4Ground –
5Ground –
6Ground –
7 Not used –
8 Power supply from main relay Input
9 Main relay coil Output
Pin No. Description Input/Output
1 and 2 Not used –
3 CAN bus low (connection with EAT ECU) Input/Output
4 CAN bus high (connection with EAT ECU) Input/Output
5 Not used –
6 Diagnostic ISO 9141 K line bus Input/Output
7 Not used –
8 Engine mount damping control actuator Output
9 Low fuel pressure sensor supply Output
10 Low fuel pressure sensor ground –
11 to 16 Not used –
17 Low fuel pressure sensor signal Input
18 to 24 Not used –
Pin No. Description Input/Output
1 MAF/IAT sensor power supply Output
2 MAF/IAT sensor air flow signal Input
3 MAF/IAT sensor ground –
4 CMP sensor signal Input
5 Not used –
6 CKP sensor signal Input
7 to 9 Not used –
10 EGR solenoid (modulator) Output
11 Fuel temperature sensor signal Input
12 Glow plug relay control Output
13 Not used –
14 Boost pressure sensor power supply Output
15 Boost pressure sensor signal Input
16 Boost pressure sensor ground –
17 CMP sensor ground –
18 Fuel temperature sensor ground –
19 CKP sensor screen ground –
20 Fuel rail pressure sensor ground –
21 and 22 Not used –
23 Boost pressure regulator Output
24 to 27 Not used –
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-15
Communications
The use of digital communication provides advantages in performance and reliability over conventional analogue
systems. There are two digital bus systems which connect with the ECM:
l CAN
l Diagnostic ISO9141 K Line bus.
Controller Area Network (CAN)
The CAN is a high speed broadcast network connected between the following electronic units:
l ECM
l EAT ECU
l Transfer box ECU
l Air Suspension ECU
l Instrument pack
l ABS ECU
l Steering angle ECU.
The CAN allows a fast exchange of data between ECU's every few microseconds. The bus comprises two wires which
are identified as CAN high (H) and CAN low (L). The two wires are coloured yellow/black (H) and yellow/brown (L)
and are twisted together to minimise electromagnetic interference (noise) produced by the CAN messages.
Diagnostics
The diagnostic socket is located in the fascia, in the driver's stowage tray. The socket is secured in the fascia panel
and is protected by a hinged cover.
28 ECT sensor signal Input
29 MAF/IAT sensor air temperature signal Input
30 Not used –
31 CKP sensor ground –
32 ECT sensor ground –
33 Fuel rail pressure sensor signal Input
34 Not used –
35 Fuel rail pressure sensor power supply Output
36 and 37 Not used –
38 Fuel rail pressure control valve Output
39 and 40 Not used –
41 Oil pressure switch signal Input
42 to 49 Not used –
50 Alternator charge signal Input
51 Engine start signal feedback Input
52 Glow plug relay fault status Input
Pin No. Description Input/Output
ENGINE MANAGEMENT SYSTEM – TD6
18-1-16 DESCRIPTION AND OPERATION
1 Cover 2 Diagnostic socket
The diagnostic socket allows the exchange of information between various ECU's on the bus systems and TestBook/
T4 or a diagnostic tool using KW2000* protocol. The information is communicated to the socket via the diagnostic ISO
9141 K line. This allows the fast retrieval of diagnostic information and programming of certain functions using
TestBook/T4 or a suitable diagnostic tool.
Engine Sensors and Actuators
The EDC system uses sensors and actuators to monitor and control the operation of the engine. The sensors supply
data to the ECM and the actuators receive signals from the ECM to control certain functions.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-17
Accelerator Pedal Position (APP) Sensor
1 Detente mechanism
2 Sensor spigot
3 Pedal
4 Springs
5 Cables
6 Bush
7 Drum
8 APP sensor
The APP sensor is located in plastic housing which is integral with the throttle pedal. The housing is injection moulded
and provides location for the APP sensor. The sensor is mounted externally on the housing and is secured with two
Torx screws. The external body of the sensor has a six pin connector which accepts a connector on the vehicle wiring
harness.
The sensor has a spigot which protrudes into the housing and provides the pivot point for the pedal mechanism. The
spigot has a slot which allows for a pin, which is attached to the sensor potentiometers, to rotate through
approximately 90°, which relates to pedal movement. The pedal is connected via a link to a drum, which engages with
the sensor pin, changing the linear movement of the pedal into rotary movement of the drum. The drum has two steel
cables attached to it. The cables are secured to two tension springs which are secured in the opposite end of the
housing. The springs provide 'feel' on the pedal movement and require an effort from the driver similar to that of a
cable controlled throttle. A detente mechanism is located at the forward end of the housing and is operated by a ball
located on the drum. At near maximum throttle pedal movement, the ball contacts the detente mechanism. A spring
in the mechanism is compressed and gives the driver the feeling of depressing a 'kickdown' switch when full pedal
travel is achieved.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-18 DESCRIPTION AND OPERATION
APP Sensor Output Graph
A = Voltage
B = APP sensor angle
C = Kick down angle
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-19
The APP sensor has two potentiometer tracks which each receive a 5V input voltage from the ECM. Track 1 provides
an output of 0.5V with the pedal at rest and 2.0V at 100% full throttle. Track 2 provides an output of 0.5V with the
pedal at rest and 4.5V at 100% full throttle. The signals from the two tracks are used by the ECM to determine fuelling
for engine operation and also by the ECM and the EAT ECU to initiate a kickdown request for the automatic
transmission.
The ECM monitors the outputs from each of the potentiometer tracks and can determine the position, rate of change
and direction of movement of the throttle pedal. The 'closed throttle' position signal is used by the ECM to initiate idle
speed control and also overrun fuel cut-off.
Mass Air Flow/Intake Air Temperature (MAF/IAT) Sensor
The MAF/IAT sensor is located on the engine air intake manifold. The sensor combines the two functions of a MAF
sensor and an IAT sensor in one unit. The sensor is housed in a plastic moulding which is connected between the
intake manifold and the air intake pipe.
The MAF sensor works on the hot film principle. Two sensing elements are contained within a film. One element is
maintained at ambient (air intake) temperature, e.g. 25° C (77°F). The other element is heated to 200°C (392°F) above
the ambient temperature, e.g. 225°C (437°F). Intake air entering the engine passes through the MAF sensor and has
a cooling effect on the film. The ECM monitors the current required to maintain the 200°C (392°F) differential between
the two elements and uses the differential to provide a precise, non-linear, signal which equates to the volume of air
being drawn into the engine.
The MAF sensor output is an analogue signal proportional to the mass of the incoming air. The ECM uses this data,
in conjunction with signals from other sensors and information from stored fuelling maps, to determine the precise fuel
quantity to be injected into the cylinders. The signal is also used as a feedback signal for the EGR system.
The IAT sensor incorporates a Negative Temperature Coefficient (NTC) thermistor in a voltage divider circuit. The
NTC thermistor works on the principle of decreasing resistance in the sensor as the temperature of the intake air
increases. As the thermistor allows more current to pass to ground, the voltage sensed by the ECM decreases. The
change in voltage is proportional to the temperature change of the intake air. Using the voltage output from the IAT
sensor, the ECM can correct the fuelling map for intake air temperature. The correction is an important requirement
because hot air contains less oxygen than cold air for any given volume.
The MAF sensor receives a 12V supply from the engine compartment fusebox and a ground connection via the ECM.
Two further connections to the ECM provide signal and signal ground from the MAF sensor.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-20 DESCRIPTION AND OPERATION
The IAT sensor receives a 5V reference voltage from the ECM and shares a ground with the MAF sensor. The signal
output from the IAT sensor is calculated by the ECM by monitoring changes in the supplied reference voltage to the
IAT sensor voltage divider circuit. The MAF/IAT sensor connector has gold plated pins to minimise resistance caused
by poor connections.
The following tables show the operating parameters for the MAF/IAT sensor.
MAF Sensor Values
IAT Sensor Values
The ECM checks the calculated air mass against the engine speed. If the calculated air mass is not plausible, the
ECM uses a default air mass figure which is derived from the average engine speed compared to a stored
characteristic map. The air mass value will be corrected using values for boost pressure, atmospheric pressure and
air temperature.
If the MAF sensor fails the ECM implements the default strategy based on engine speed. In the event of a MAF sensor
signal failure, any of the following symptoms may be observed:
l Difficult starting
l Engine stalls after starting
l Delayed engine response
l Emission control inoperative
l Idle speed control inoperative
l Reduced engine performance.
Air Mass kg/h Current Draw µA
15 1.4225
30 1.7616
50 2.0895
60 2.2270
120 2.8356
220 3.4558
250 3.5942
370 4.0291
480 4.3279
640 4.6601
Temperature °C (°F) Resistance kΩ
-30 (-22) 22.960
-20 (-4) 13.850
-10 (14) 8.609
0 (32) 5.499
10 (50) 3.604
20 (68) 2.420
30 (86) 1.662
40 (104) 1.166
50 (122) 0.835
60 (140) 0.609
70 (158) 0.452
80 (176) 0.340
90 (194) 0.261
100 (212) 0.202
110 (230) 1.159
120 (248) 0.127
130 (266) 1.102
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-21
If the IAT sensor fails the ECM uses a default intake air temperature of -5°C (23°F). In the event of an IAT sensor
failure, any of the following symptoms may be observed:
l Over fuelling, resulting black smoke emitting from the exhaust
l Idle speed control inoperative.
Boost Pressure (BP) Sensor
The BP sensor is located on the rear of the inlet manifold, adjacent to the fuel rail pressure sensor. The sensor
provides a voltage signal to the ECM relative to the intake manifold pressure. The BP sensor has a three pin connector
which is connected to the ECM and provides a 5V reference supply from the ECM, a signal input to the ECM and a
ground for the sensor.
The BP sensor uses piezo ceramic crystals. These are sensitive to pressure changes and oscillate at different rates
according to air pressure. The oscillation changes the resistance of the piezo crystal. The resistance through the
crystal produces an output voltage from the sensor of between 0 and 5V, proportional to the pressure in the intake
manifold. A signal of 0V indicates low pressure and 5V indicates high pressure. This signal is processed by the ECM
which determines the manifold pressure by comparing the signal to stored values. The ECM then uses the signal for
the following functions:
l Maintain manifold boost pressure
l Reduce exhaust smoke emissions when driving at high altitude
l Control of the EGR system
l Control of the vacuum control module.
If the BP sensor fails, the ECM uses a default pressure of 0.9 bar (13 lbf/in
2
). In the event of a BP sensor failure, the
following symptoms may be observed:
l Altitude compensation inoperative (black smoke emitted from the exhaust)
l Active boost control inoperative.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-22 DESCRIPTION AND OPERATION
Boost Control Solenoid Valve
The boost control solenoid valve is located in the RH side of the engine compartment and is attached to the RH inner
wing, below the vacuum reservoir. The solenoid valve is identical in its construction to the EGR modulator.
The boost control solenoid valve is used by the ECM to control the Variable Nozzle Turbine (VNT) within the
turbocharger unit. The solenoid valve receives a battery voltage via the main relay in the E-box. The ECM controls
the ground for the solenoid.
The ground for the solenoid is controlled using PWM. The ECM controls the duty cycle of the PWM ground to
determine the amount of vacuum supplied to the VNT. The VNT improves turbine boost pressure by varying the gas
flow of the turbine. This is controlled by a vacuum actuator located on the turbo, which moves a rod which in turn
changes the angle of the guide vanes.
+ MANIFOLDS AND EXHAUST SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
If the boost control solenoid valve fails, the vanes remain in the fully open position. In the event of solenoid valve
failure, the following symptom will be observed:
l The engine will produce less torque at lower engine speeds.
The solenoid coil has a resistance of 15.4 ±7.0Ω at 20°C (68°F). The solenoid valve can be activated using TestBook/
T4 for test and diagnostic purposes.
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is located on the LH side of the cylinder head, between the two rear air inlet ports. The ECT sensor
provides the ECM and the instrument pack with engine coolant temperature status.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-23
The ECM uses the temperature information for the following functions:
l Fuelling calculations
l Limit engine operation if engine coolant temperature becomes too high
l Cooling fan operation
l Glow plug activation time.
The instrument pack uses the temperature information for the following functions:
l Temperature gauge operation.
The engine coolant temperature signal is also transmitted on the CAN by the instrument pack for use by other
systems.
The ECM ECT sensor circuit consists of an internal voltage divider circuit which incorporates an NTC thermistor. As
the coolant temperature rises the resistance through the sensor decreases and visa versa. The output from the sensor
is the change in voltage as the thermistor allows more current to pass to earth relative to the temperature of the
coolant.
The ECM compares the signal voltage to stored values and adjusts fuel delivery to ensure optimum driveability at all
times. The engine will require more fuel when it is cold to overcome fuel condensing on the cold metal surfaces inside
the combustion chamber. To achieve a richer air/fuel ratio, the ECM extends the injector opening time. As the engine
warms up the air/fuel ratio is leaned off.
The input to the sensor is a 5V reference voltage supplied from the voltage divider circuit within the ECM. The ground
from the sensor is also connected to the ECM which measures the returned current and calculates a resistance figure
for the sensor which relates to the coolant temperature.
The following table shows engine coolant temperature values and the corresponding sensor resistance values.
If the ECT sensor fails, the following symptoms may be observed:
l Difficult cold start
l Difficult hot start
l Engine performance compromised
l Temperature gauge inoperative or inaccurate reading.
In the event of ECT sensor signal failure, the ECM applies a default value of 80°C (176°F) coolant temperature for
fuelling purposes. The ECM will also permanently operate the cooling fan at all times when the ignition is switched
on, to protect the engine from overheating.
Engine Coolant Temperature °C (°F) Sensor Resistance kΩ
-55 (-67) 536.319
-40 (-40) 187.396
-30 (-22) 98.571
-20 (-4) 54.058
-10 (14) 30.813
0 (32) 18.183
10 (50) 11.082
20 (68) 6.956
30 (86) 4.487
40 (104) 2.967
50 (122) 2.006
60 (140) 1.386
70 (158) 0.9757
80 (176) 0.7006
90 (194) 0.5111
100 (212) 0.3773
110 (230) 0.2844
120 (248) 0.2168
130 (266) 0.1666
140 (284) 0.1302
150 (302) 0.1027
ENGINE MANAGEMENT SYSTEM – TD6
18-1-24 DESCRIPTION AND OPERATION
Fuel Temperature Sensor
The fuel temperature sensor is located in a plastic housing, behind the fuel cooler on the LH side of the engine
compartment. The sensor is positioned in the return fuel flow from the engine and measures the fuel temperature
returning from the engine to the fuel tank.
The sensor is an NTC sensor which is connected to the ECM by two wires. The ECM fuel temperature sensor circuit
consists of an internal voltage divider circuit which incorporates an NTC thermistor. As the fuel temperature rises the
resistance through the sensor decreases and visa versa. The output from the sensor is the change in voltage as the
thermistor allows more current to pass to earth relative to the temperature of the fuel.
The ECM monitors the fuel temperature constantly. If the fuel temperature exceeds 85°C (185°F), the ECM invokes
an engine 'derate' strategy. This reduces the amount of fuel delivered to the injectors in order to allow the fuel to cool.
When this occurs, the driver may notice a loss of performance.
Further fuel cooling is available by a bi-metallic valve diverting fuel through the fuel cooler when the fuel reaches a
predetermined temperature. In hot climate markets, an electrically operated cooling fan is positioned in the air intake
ducting to the fuel cooler. This is controlled by a thermostatic switch, which switches the fan on and off when the fuel
reaches a predetermined temperature.
+ FUEL DELIVERY SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-25
Low Pressure (LP) Fuel Sensor
The LP fuel sensor is located in a port on the top of the fuel filter and sealed to the filter with an O-ring seal and secured
with a clamp plate and screw. The sensor monitors the absolute fuel pressure between the fuel filter and the high
pressure fuel pump. The ECM uses the sensor to ensure that fuel is being supplied to the high pressure fuel pump at
the correct rate. During engine start-up, only the LP fuel sensor signal is used. When the engine is running, the ECM
compares the LP fuel sensor signal and a nominal pre-programmed 'setpoint' value.
The low fuel pressure sensor is connected by three wires to ECM. The three connections provide a 5V supply to the
sensor, an earth and a variable signal back to the ECM which corresponds to the fuel pressure.
The sensor measures the pressure on the output side of the filter and therefore can detect a blockage within the filter
or failure of the LP fuel supply. The ECM will monitor the LP fuel sensor and, in the event of very low pressure, will
stop the engine to prevent damage to the HP injector pump.
+ FUEL DELIVERY SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
The wires to the fuel sensor are monitored by the ECM for short and open circuit. The ECM also monitors the 5V
supply. If a failure occurs a fault is recorded in the ECM memory and the ECM uses a default fuel pressure value.
If the ECM registers an 'out of range' deviation between the pressure signal from the sensor and the pre-programmed
'setpoint' a fault is stored in the ECM memory. Depending on the extent of the deviation, the ECM will reduce the
injection quantity, stop the engine immediately or prevent further engine starting.
NOTE: In addition to the low pressure supply to the high pressure fuel pump, the pressure in the fuel line is of equal
importance with regard to correct fuel injection. The pressure in the fuel return line must not exceed 1.5 bar (22 lbf/
in
2
). If the pressure in the return line exceeds this figure, the pressure differential across the high pressure fuel pump
will be unbalanced and incorrect priming of the fuel rail will occur. The ECM does not monitor the return line pressure.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-26 DESCRIPTION AND OPERATION
Fuel Rail Pressure Sensor
The fuel rail pressure sensor is located on the end of the fuel rail, at the rear of the engine compartment. The sensor
uses a diaphragm in contact with the pressurised fuel. The diaphragm is attached to a piezo crystal which changes
resistance as the diaphragm reacts to changes in fuel pressure. The deflection of the diaphragm equates to
approximately 1 mm per 500 bar (7252 lbf/in
2
).
The ECM supplies the fuel pressure sensor with a 5V reference voltage to a bridge circuit. The returned voltage,
depending on pressure, is in the range of 0 – 70 mV. This is passed through an evaluation switch within the sensor
and outputs an analogue signal to the ECM which can be between 0.5 and 4.5V. The ECM compares the received
signal voltage against stored data and converts the signal into a fuel pressure value.
The ECM uses the pressure value to control the fuel rail pressure control valve located on the high pressure pump,
to control the fuel pressure supplied to the fuel rail and the injectors. The ECM also uses the fuel rail pressure signal
in conjunction with the LP fuel sensor signal to calculate the 'setpoint' pressure used during engine operation.
The ECM will monitor the fuel rail pressure only if the engine speed is greater than 550 rev/min, the fuel rail pressure
control valve is operational and there is no stored faults for the fuel rail pressure sensor. The ECM monitors the
following fuel rail pressure related variables:
l fuel rail pressure within maximum and minimum limits
l controlled variable at fuel rail pressure control valve within minimum and maximum limits
l plausibility of rail pressure and controlled pressure variable.
If the ECM registers an 'out of range' deviation for any of the above a fault is stored in the ECM memory. This result
in immediate engine shutdown.
Possible causes of the 'out of range' deviation are as follows:
l fuel tank empty
l fuel system problem upstream of high pressure fuel pump
l internal or external leakage in the high pressure system
l high pressure fuel pump output inadequate (pump failure)
l injector leak-off rate excessive
l control quantity for injectors too high
l fuel rail pressure control valve failure.
The wires to the pressure sensor are monitored by the ECM for short and open circuit. The ECM also monitors the
5V supply. If a failure occurs a fault is recorded in the ECM memory. The ECM uses a default rail pressure value which
results in the injection quantity being limited.
In the event of a failure of the fuel rail pressure sensor, the following symptoms may be observed:
l Engine will not start
l Severe loss of power
l Engine stalls.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-27
Fuel Rail Pressure Control Valve
The fuel rail pressure control valve is located on the high pressure fuel pump. The control valve regulates the fuel
pressure within the fuel rail and is controlled by the ECM. The control valve is an electrically operated solenoid valve
which is either open or closed.
When the solenoid is de-energised, an internal spring holds an internal valve closed. At fuel pressure of 100 bar (1450
lbf/in
2
) or higher, the force of the spring is overcome, opening the valve and allowing fuel pressure to decay into the
fuel return pipe. When the pressure in the fuel rail decays to approximately 100 bar (1450 lbf/in
2
) or less, the spring
force overcomes the fuel pressure and closes the valve. When the ECM energises the solenoid, the valve is closed
allowing the fuel pressure to build. The pressure in the fuel rail in this condition can reach approximately 1300 bar
(18854 (1450 lbf/in
2
).
The ECM controls the fuel rail pressure by operating the control valve solenoid using a PWM signal. By varying the
duty cycle of the PWM signal, the ECM can accurately control the fuel rail pressure and hence the pressure delivered
to the injectors according to engine load. This achieved by the control valve allowing a greater or lesser volume of fuel
to pass from the high pressure side of the pump to the unpressurised fuel return line, regulating the pressure on the
high pressure side.
The fuel rail pressure control valve receives a PWM signal from the ECM of between 0 and 12V. The ECM controls
the operation of the control valve using the following information to determine the required fuel pressure:
l Fuel rail pressure
l Engine load
l Accelerator pedal position
l Engine temperature
l Engine speed.
In the event of a total failure of the fuel rail pressure control valve, the following symptoms may be observed:
l Engine will not start
l Severe loss of power
l Engine stalls.
In the event of a partial failure of the fuel rail pressure control valve, the ECM will activate the solenoid with the
minimum sampling ratio which results in the injection quantity being limited.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-28 DESCRIPTION AND OPERATION
Brake Light Switch
The brake switch is located on the pedal box and is operated by the brake pedal. The switch is a Hall effect switch
which detects the position of the brake pedal and determines when the driver has applied the brakes. The switch is
connected directly to the ECM.
The brake switch consists of an inner sensor in an outer mounting sleeve. To ensure correct orientation, the sensor
is keyed to the mounting sleeve and the mounting sleeve is keyed to the pedal mounting bracket. Mating serrations
hold the sensor in position in the mounting sleeve. While the brakes are off, the tang on the brake pedal rests against
the end of the sensor. When the brake pedal is pressed, the tang moves away from the sensor and induces a change
of sensor output voltages. This is sensed by the ECM which detects that the brake pedal has been applied. The ECM
uses the brake signal for the following:
l To limit fuelling during braking
l To inhibit/cancel cruise control if the brakes are applied.
In the event of a brake switch failure, the following symptoms may be observed:
l Cruise control inactive
l Increased fuel consumption.
Crankshaft Position (CKP) Sensor
The CKP sensor is located on the LH side of the engine block, below the starter motor. The sensor is sealed in the
block with an O-ring seal and secured with a screw. The sensor tip is aligned with a target (reluctor) which is attached
to the crankshaft. The sensor produces a sine wave signal with speed dependant amplitude, the frequency of which
is proportional to engine speed.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-29
The ECM monitors the CKP sensor signal and can detect engine overspeed. The ECM counteracts engine overspeed
by gradually fading out speed synchronised functions.
The CKP sensor operates on the variable reluctance principle. This principle uses the disturbance of the magnetic
field which is generated at the tip of the sensor. The disturbance of the magnetic field is caused by the reluctor on the
crankshaft passing the sensor tip.
The reluctor is a steel ring with 58 teeth and a space with two teeth missing. The teeth and the spaces between them
represent 3° of crankshaft rotation. The two missing teeth provide a reference point for the angular position of the
crankshaft.
As the reluctor rotates, the teeth passing the CKP sensor tip produce a sinusoidal waveform which is interpreted by
the ECM as the velocity of the crankshaft. When the space with the two missing teeth pass the sensor tip, a gap in
the signal is produced which the ECM uses to determine the crankshaft position. The air gap between the sensor tip
and the reluctor is important to ensure correct signals are output to the ECM
The ECM uses the signal from the CKP sensor for the following functions:
l Determine fuel injection timing
l Enable the fuel pump relay circuit (after the priming period)
l Produce an engine speed signal which is broadcast on the CAN for use by other systems.
The CKP sensor is connected to the ECM by two wires which are both outputs. The CKP sensor is screened to protect
the signals from interference. The screen is connected to earth via the ECM.
In the event of CKP sensor failure, the following symptoms may be observed:
l Engine cranks, but fails to start
l Engine misfires
l Engine runs roughly or stalls.
The operation of the CKP sensor is monitored by software within the ECM. Fault codes are recorded within the ECM
if sensor malfunction occurs.
Camshaft Position (CMP) Sensor
The CMP sensor is located in a hole in the top of the camshaft cover. The sensor is sealed in the cover with an O-
ring seal and secured with a screw. The sensor tip is aligned with a target which is integral with the inlet camshaft.
The target design produces one square wave signal pulse for every full rotation of the camshaft.
The ECM uses the CMP sensor signal to determine if the piston in No. 1 cylinder is at injection TDC or exhaust TDC.
Once this has been established, the ECM can then operate the correct injector to inject fuel into the cylinder when the
piston is at injection TDC.
The CMP sensor is a Hall effect sensor which used by the ECM at engine start-up to synchronise the ECM with the
CKP sensor signal. The ECM does this by using the CMP sensor signal to identify number one cylinder to ensure the
correct injector timing. Once the ECM has established the injector timing, the CMP sensor signal is no longer used.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-30 DESCRIPTION AND OPERATION
The CMP sensor receives a 12V supply from the ECM. Two further connections to the ECM provide ground and signal
output.
If a fault occurs, an error is registered in the ECM. Two types of failure can occur; camshaft signal frequency too high
or total failure of the camshaft signal. The error recorded by the ECM can also relate to a total failure of the crankshaft
signal or crankshaft signal dynamically implausible. Both components should be checked to determine the cause of
the fault.
If a fault occurs with the CMP sensor when the engine is running, the engine will continue to run but the ECM will
deactivate boost pressure control. Once the engine is switched off, the engine will crank but will not restart while the
fault is present.
Fuel Injector
There are six electronic fuel injectors (one for each cylinder) located in a central position between the four valves of
each cylinder. The ECM divides the injectors into two banks of three with cylinders 1 to 3 being designated bank 1
and cylinders 4 to 6 designated bank 2.
+ FUEL DELIVERY SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
Each injector is supplied with pressurised fuel from the fuel rail and delivers finely atomised fuel directly into the
combustion chambers. Each injector is individually controlled by the ECM which operates each injector in the firing
order and controls the injector opening period via PWM signals.
Each injector receives a 12V supply via the main relay. The ECM controls the ground for each injector solenoid and,
using programmed injection/timing maps and sensor signals, determines the precise pilot and main injector timing for
each cylinder.
If battery voltage falls to between 6 and 9V, fuel injector operation is restricted, affecting emissions, engine speed
range and idle speed. In the event of a failure of a fuel injector, the following symptoms may be observed:
l Engine misfire
l Idle irregular
l Reduced engine performance
l Reduced fuel economy
l Difficult starting
l Increased smoke emissions.
The ECM monitors the wires for each injector for short circuit and open circuit, each injector solenoid coil and the
transient current within the ECM. If a defect is found, an error is registered in the ECM for the injector in question.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-31
The voltage in the injector output stages is monitored. If a fault occurs it is registered in the memory as capacitor
voltage 1 for cylinders 1, 2, 3 and capacitor voltage 2 for cylinders 4, 5, and 6. If a fault occurs of the type 'current on
high side too high' or 'current on low side too high', it is assigned to a particular injector. The cause of this fault can
be in any of the wires to the three cylinders in that bank because the wires for each bank are bundled.
If a fault occurs of the type 'current on high side too high' or 'current on low side too high', the ECM will stop the engine.
If the fault is of the type 'load drop', signifying a break in the wiring, the ECM will maintain the engine running providing
not more than one injector is affected. Any fault in the injector output stages will result in the ECM stopping the engine.
When an injector is installed in the cylinder head, care must be taken to ensure that the mounting claw is in the correct
position, the flat side of the claw must face upwards. If the claw is installed incorrectly, the injector will be wrongly
installed resulting in the seal at the base of the injector being ineffective and the injector will be loose in the cylinder
head.
Injector Calibration – To compensate for tolerances in the fuel injection system, a characteristic map with engine
specific compensation values is programmed into the ECM on production. If one or more injectors is replaced, the
calibration function must be performed to reset the compensation values to 0. This must only be performed when
injectors are removed and replaced with new items. The calibration procedure must only be used for this purpose.
The procedure is performed using TestBook/T4 and following the on-screen instructions.
Exhaust Gas Recirculation (EGR) Modulator
The EGR modulator is located on a bracket on the LH side of the engine block, near the starter motor. The EGR
modulator is a solenoid operated valve which regulates the vacuum supplied to the EGR valve, causing it to open or
close. The ECM uses the EGR modulator to control the amount of exhaust gas being recirculated in order to reduce
exhaust emissions and combustion noise. The EGR is enabled when the engine is at normal operating temperature
and under cruising conditions.
The EGR modulator receives a 12V supply from the main relay. The ground for the solenoid is via the ECM and is
controlled using a PWM signal. The PWM duty signal of the solenoid ground is varied to determine the precise amount
of vacuum supplied to the EGR valve, and consequently the volume of exhaust gas delivered to the cylinders.
In the event of a failure of the EGR modulator, the EGR function will become inoperative. The ECM can monitor the
EGR modulator solenoid for short circuits and store fault codes in the event of failure. The modulator can also be
activated for testing using TestBook/T4.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-32 DESCRIPTION AND OPERATION
Engine Mounting Damping Control Actuator
The mounting damping system comprises two hydraulic mounts with controlled damping characteristics, a control
actuator, the ECM and the pneumatic vacuum lines.
The damping system provides the following benefits:
l Increased passenger comfort at idle speed
l Isolation of engine vibration
l Reduction in natural resonance of engine induced by uneven road surfaces
l Reduction in engine judder when engine is stopped.
The engine mounting damping control system uses vacuum taken from a connection in the vacuum line between the
vacuum pump and the brake booster. The vacuum is in the range of 0.5 – 0.9 bar (7.20 – 13.05 lbf/in
2
). Vacuum is
supplied simultaneously to both mounts when the engine is idling and in the speed range close to idling.
The engine mounting damping control actuator is located on a bracket on the LH side of the engine block, behind the
EGR modulator, near the starter motor. The actuator is a solenoid operated valve which regulates the vacuum
supplied to the engine mountings. The ECM uses the actuator to control the damping of the mountings. When the
actuator solenoid is de-energised, the engine mountings are hard. When the ECM energises the actuator solenoid,
the vacuum is applied to the mountings and they become soft. The ECM controls the actuator solenoid using a PWM
signal and can vary the damping of the engine mounts according to operating conditions.
+ ENGINE – Td6, DESCRIPTION AND OPERATION, Description.
The engine mounting damping control actuator receives a 12V supply from the main relay. The ground for the solenoid
is via the ECM.
In the event of a failure of the engine mounting damping control actuator, the damping control will become inoperative.
The ECM can monitor the actuator solenoid for short circuits and store fault codes in the event of failure. The engine
mounting damping control actuator can also be activated for testing using TestBook/T4.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-33
Glow Plug Relay
1 Fusible link (100A) 2 Glow plug relay
The glow plug relay is located in the E-box. The ECM uses the glow plug relay to control operation of the glow plugs.
Operation of the glow plug relay and the glow plugs is indicated to the driver via a glow plug warning lamp in the
instrument pack.
The glow plug relay is supplied with a permanent power feed directly from the battery, via a 100A fusible link located
on the bulkhead, behind the battery. A second power feed is also supplied via the main relay and fuse 2 in the engine
compartment fusebox. The relay is connected to ground directly to the vehicle body.
The glow plug relay is also connected to the ECM which supplies engine coolant temperature and pre-heat and post
heat timer calculations. The relay processes this data and provides the appropriate output control for the glow plugs.
In the event of glow plug relay failure, the following symptoms may be observed:
l Difficult starting
l Excessive smoke emissions after starting.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-34 DESCRIPTION AND OPERATION
Glow Plugs
Six glow plugs are located in the cylinder head, on the inlet side. The glow plugs and the glow plug relay are a vital
part of the engine starting strategy. The glow plugs heat the air inside the cylinder during cold starts to assist
combustion. The use of glow plugs helps reduce the amount of additional fuel required on start-up, and consequently
reduces the emission of black smoke. The use of glow plugs also reduces the amount of injection advance required,
which reduces engine noise, particularly when idling with a cold engine.
The main part of the glow plug is a tubular heating element which protrudes into the combustion chamber of the
engine. The heating element contains a spiral filament encased in magnesium oxide powder. At the tip of the tubular
heating element is the heater coil. Behind the heater coil, and connected in series, is a control coil. The control coil
regulates the heater coil to ensure that it does not overheat.
Pre-heat is the length of time the glow plugs operate prior to engine cranking. The ECM controls the pre-heat time
based on ECT sensor output and battery voltage. If the ECT sensor fails, the ECM will use the IAT sensor value as a
default value. The pre-heat duration is extended if the coolant temperature is low and the battery is not fully charged.
Post heat is the length of time the glow plugs operate after the engine starts. The ECM controls the post heating time
based on ECT sensor output. The post heat phase reduces engine noise, improves idle quality and reduces
hydrocarbon emissions.
When the ignition is switched on to position II, the glow plug warning lamp illuminates and the instrument pack
displays' PREHEATING' in the message centre. The engine should not be cranked until the glow warning lamp goes
off.
In the event of glow plug failure, the following symptoms may be observed:
l Difficult starting
l Excessive smoke emissions after starting.
The glow plug warning lamp also serves a second function within the EDC system. If a major EDC system fault occurs,
the glow plug warning lamp will be illuminated permanently and a message generated in the instrument pack. The
driver must seek attention to the engine management system at a Land Rover dealer as soon as possible.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-35
Operation
General
The ECM controls the operation of the engine using information stored in its memory in the form of maps. The maps
contain data which is used to determine the most efficient fuelling for any given driving condition. The ECM also has
maps for the operation of sub-systems such as EGR.
The ECM is an adaptive unit which learns the characteristics of the vehicle components. This feature allows the ECM
to compensate for any variations in components fitted to the vehicle in production, and to adapt to changes of
components which may occur in service. The ability to compensate for 'wear and tear' and environmental changes
during the life of the vehicle ensures that the ECM can comply with emission control legislation over extended periods.
The ECM is programmed with a 'strategy' which controls the decisions about when to turn specific functions on and
off. The inputs to this decision making process are supplied by sensors, mounted at various locations on the vehicle,
which supply information to the ECM. If a sensor fails to supply information, the ECM, where possible, will use data
from other sensors and use a default value for the missing information. In cases where default values cannot be used,
the vehicle will be disabled. Use of a default value may result in reduced performance, increased fuel consumption
and exhaust emissions.
The ECM is programmed with vehicle specific information known as 'calibration'. This data is used to calculate ECM
outputs. This information, together with data inputs from sensors and other system ECU's, determines output signals
from the ECM to the actuators.
The ECM uses strategies such as:
l Smoke limitation
l Active surge damping
l Automatic gear change
l Fuel reduction
l Engine cooling
l Combustion noise limitation.
During idle and wide open throttle conditions, the ECM uses mapped data to respond to the input signals from the
APP sensor. To implement the optimum fuelling strategy for idle and wide open throttle, the ECM requires input data
from the following sensors:
l CKP sensor
l APP sensor
l ECT sensor
l MAF/IAT sensor
l Fuel rail pressure sensor.
This data is then compared to mapped data within the ECM to control acceleration using the following actuators and
controllers:
l EGR modulator – closed for cleaner combustion
l Fuel pressure control valve – increase fuel pressure supplied to fuel rail
l Electronic fuel injectors – change injector duration
l A/C compressor clutch relay – de-energised during wide open throttle to reduce engine load
l EAT ECU – kickdown activation.
During cold start conditions, the ECM uses ECT sensor data to determine if the cold start strategy is required. During
cold start conditions, the ECM will inject more fuel into the cylinders and will initiate the glow plug timing strategy for
effective cold starting. Normal fuel strategy is used during hot starts.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-36 DESCRIPTION AND OPERATION
Injection Control
The purpose of the injection control is to deliver a precise quantity of finely atomised fuel into the combustion
chambers at the correct times in the engine cycle. To precise control the fuel injection quantity and timing, the
following data must be available to the ECM:
l Crankshaft speed and position: This information enables the ECM to determine the volume of air induced into
the cylinders and the position of the crankshaft for timing purposes.
l Camshaft position: This data enables the ECM to determine the relative positions of the crankshaft and
camshaft for timing purposes.
l Injection timing map: This data provides the basic data which is used by the ECM when calculating the injection
timing and quantity.
l Engine coolant temperature: This information is used, in conjunction with the CKP sensor data and the fuelling
map, to set the injection quantity to the correct value.
l Fuel rail pressure: This data is used during fuelling calculations to correct the electrical opening times (injector
duty cycle) to compensate for variations in fuel pressure.
l Mass air flow: This data is used by the ECM to calculate the mass of air which has entered the cylinders and
consequently the volume of oxygen available for combustion with the fuel. It also allows the ECM to monitor EGR
flow when the EGR system is active.
l Intake air temperature: This data is required by the ECM to provide a correction factor for differing intake air
temperatures. Cold air contains more oxygen than hot air for any given volume, therefore the fuelling must be
adjusted to suit the current conditions.
l Accelerator pedal position: This data is vital to the operation of the ECM and the vehicle. The ECM interprets
the electrical signals from the APP sensor as throttle demand and controls the power output of the engine
accordingly.
Pilot Fuel Injection
Pilot fuel injection helps reduce engine clatter and vibration. The ECM provides this feature by opening the electronic
fuel injectors briefly, before injecting the main charge of fuel. This makes the flame front propagation through the main
charge less abrupt, giving reduced levels of diesel knock.
Smoke Limitation
This requires high injection pressure to improve the atomisation of the fuel injected into the cylinders. By maintaining
high fuel pressures at low engine speeds, the ECM maximises the atomisation of the fuel for conditions where
turbulence in the combustion chamber is reduced.
The strategy contained in the ECM does not allow more fuel to be injected than there is oxygen in the cylinders.
Active Surge Damping
Active surge damping is implemented to prevent the engine surging when the EAT ECU initiates a gear change. The
ECM reduces fuelling to lower the engine torque output, thereby preventing engine surge and consequently providing
a smooth gear change.
Variable Nozzle Turbine (VNT)
The VNT makes it possible to vary the exhaust gas flow of turbine by changing the angle that the turbine guide vanes
are set at. With the guide vanes in a closed position, the exhaust gas flow is reduced and the gas flow to the turbine
wheel is increased. This results in increased boost pressure.
The boost pressure sensor provides a feed back signal to the ECM relative to the inlet manifold pressure. The ECM
also calculates engine load and uses this along with the boost pressure sensor signal to send a PWM signal to the
boost control solenoid valve to determine the amount of vacuum supplied to the boost control vacuum actuator on the
turbocharger. The amount of vacuum operates between 0 mbar and 640 mbar depression. At 640 mbar the vanes
are fully closed providing maximum boost.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-37
Crankshaft and Camshaft Synchronisation
The crankshaft and camshaft must be synchronised for the engine to start. The CKP sensor registers the crankshaft
position. The ECM calculates from the signal the TDC positions (exhaust or injection TDC). The ECM uses the CMP
sensor signal to determine which TDC position relates to exhaust or injection.
The ECM compares the two signals to provide the correct injector sequence. The injector sequence is then repeated
corresponding to the engine firing order 1–5–3–6–2–4.
If a valid signal from the CMP sensor is not received after two full engine revolutions, fuel injection is terminated and
the engine will not start.
Electric Fuel Pump and Fuel Rail Pressure Control Valve
The electric fuel pumps and the fuel rail pressure control valve are similar in their activation by the ECM. The pumps
and the control valve are both energised for 60 seconds from the ignition switch being moved to position II. This time
period is variable depending on engine coolant temperature and the characteristics of the components.
This strategy is implemented to prevent thermal damage poor cooling or non productive pumping of fuel against an
inactive high pressure fuel pump with the engine not running. When engine speed increases past 50 rev/min both
components are activated continuously until the ignition is switched off.
In the event of a crash, the SRS Diagnostic Control Unit (DCU) generates a message which is passed to the
instrument pack and passed on the CAN to the ECM. This message causes the ECM to shut down the electric fuel
pumps which cannot be reactivated until the ignition is switched off and then on again.
+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description.
Air Conditioning (A/C)
The ATC ECU sends a message via the K bus to the instrument pack which is then passed on the CAN to the ECM
that the ATC ECU is preparing to activate the A/C compressor clutch. If all engine operating conditions are correct the
ECM will respond with an OK signal. If engine conditions are not correct for additional loads to be applied to the
engine, the ECM will refuse the A/C on request. This message is returned from the ECM on the CAN to the instrument
pack and then passed to the ATC ECU on the K bus.
When high engine torque is required (pulling away from rest or accelerating), the ATC ECU compressor control logic
shuts down the A/C compressor to ensure that sufficient engine torque is available.
+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Operation.
Cooling Strategy
The ECM controls the electric cooling fan operation for the engine, automatic transmission and air conditioning. With
the ECM in full control of the cooling fan, it can also adjust injector duration and timing to compensate for additional
engine load imposed by the alternator during cooling fan operation. The cooling fan is controlled using PWM signals
to provide up to 15 different fan speeds. The ATC ECU requests cooling fan operation for condenser cooling under
certain conditions.
+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Operation.
Operation of the cooling fan will be given priority to operate for engine cooling, overriding any request from the ATC
ECU. The fan speed for engine cooling is dependant on engine coolant temperature and current road speed.
The ECM will allow the cooling fan to 'run-on' after the engine is stopped. This is limited by engine coolant temperature
or a maximum run-on time. If the ECT sensor fails a default value is used and the cooling fan will run permanently.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-38 DESCRIPTION AND OPERATION
Electronic Automatic Transmission (EAT) ECU Strategy
The EAT ECU implements an idle neutral strategy, which forms part of the fuel reduction strategy. Neutral is selected,
reducing engine load and fuel consumption, when all of the following conditions are met:
l ECM confirms engine is at idle
l 'D' selected on transmission selector lever
l Foot brake applied.
If one of these conditions changes after neutral has been selected, drive 'D' will automatically be reselected.
When the EAT ECU is changing gear, it requests on the CAN for a reduction in engine torque. The ECM reduces the
engine torque output momentarily while the gear change is in progress by reducing the fuel delivery to the injectors.
This ensures smooth gear changes throughout the engine speed and load ranges and also reduces exhaust
emissions.
The ECM sends the following data to the EAT ECU using the CAN:
l Accelerator pedal position
l Engine torque
l Engine speed
l Engine coolant temperature
l Ignition key position
l Virtual throttle angle.
The EAT ECU sends the following data to the ECM using the CAN:
l Torque reduction request
l Selector lever position
l Current gear
l Gear change in progress
l Additional cooling request.
Immobilisation System
The ECM plays a major role in the immobilisation of the vehicle. The ECM prevents engine fuelling until it receives a
valid coded signal from the immobilisation ECU. The coded signal from the immobilisation ECU is supplied in the form
of a rolling code, preventing the code from being copied or by-passed.
When new, the immobilisation ECU is blank and is programmed with a starting code known as a 'seed'. The seed is
then used as a base point for the rolling code when the immobilisation ECU is synchronised to the ECM during
manufacture.
Once synchronised, the ECM and the immobilisation ECU are not interchangeable and operate as a matching pair.
When a new ECM is fitted to a vehicle during service, the new immobilisation ECU must be supplied with a seed which
matches the vehicle. The rolling codes in the new immobilisation ECU and the existing ECM must be synchronised
using TestBook/T4.
The immobilisation ECU receives an engine speed signal from the ECM to inhibit starter motor operation when the
engine is running, to prevent damage to the starter motor and ring gear. Engine speed information is broadcast on
the CAN by the ECM. The instrument pack passes the engine speed signal on the K bus to other systems, including
the immobilisation ECU.
Cruise Control
The ECM incorporates a cruise control program which controls all functions of the cruise control system.
During cruise control operation, the ECM controls vehicle speed by adjusting fuel injection duration and timing. When
the accelerator pedal is pressed with cruise control active, the ECM outputs a calculated throttle angle signal in place
of the actual throttle angle signals produced by the APP sensor. The calculated throttle angle is derived from fuel
demand.
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-39
DESCRIPTION AND OPERATION
Cruise Control Component Location
1 Instrument pack
2 Cruise control switches
3 Anti-lock Brake System (ABS) ECU
4 Brake switch
5 Accelerator Pedal Position (APP) sensor
6 Engine Control Module (ECM)
ENGINE MANAGEMENT SYSTEM – TD6
18-1-40 DESCRIPTION AND OPERATION
Cruise Control, Control Diagram
A = Hardwired connection; D = CAN bus; J = Diagnostic ISO9141 K Line; K = I bus
M18 0793M18 0793A
K
A
12
3
4
6
7
9
8
10
12
13
11
JJ
D
5
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-41
1 Fuse 30A
2 Cruise control switches
3 Rotary coupler
4 Instrument pack
5 EAT ECU
6 ABS ECU
7 Brake switch
8 Diagnostic socket
9 Fuel injectors
10 APP sensor
11 ECM
12 Fuse 5A
13 Ignition switch
ENGINE MANAGEMENT SYSTEM – TD6
18-1-42 DESCRIPTION AND OPERATION
Description
General
The cruise control system is integrated with the engine management system and uses fuelling intervention to
automatically maintain a set vehicle speed. Once engaged, the system can also be used to accelerate the vehicle
without using the accelerator pedal. The cruise control system comprises the following components:
l On/Off/Suspend switch
l '+' and '–' (set/accelerate and decelerate) steering wheel switches
l Resume switch
l Rotary coupler
l Cruise control warning lamp.
The cruise control system also uses inputs from the brake pedal switch, the APP sensor, the ECM and the ABS ECU.
The cruise control is operated by the driver using only the steering wheel switches. When cruise is active, the ECM
regulates the PWM signals to the fuel injectors to adjust the fuel supply as required to maintain the set speed.
Control Switches
1 Resume switch
2 Set/Accelerate switch
3 Decelerate switch
4 On/Suspend/Off switch
5 Steering wheel heater switch (if fitted – Ref.
only)
The cruise control switches are located on the RH side of the steering wheel. The switches are connected via flyleads
directly to the rotary coupler. All of the cruise control switches are non-latching momentary switches.
The minimum set speed for cruise control is 17 mph (27 (km/h), the maximum set speed is 155 mph (250 km/h).
Cruise control is automatically switched off if the vehicle speed falls below 15 mph (24 km/h).
On/Suspend/Off Switch
The on/suspend/off switch controls the selection of cruise control. When the ignition is in position II, a single press of
the switch will activate the cruise control system. A subsequent press of the switch activates the suspend mode, which
temporarily switches off the cruise system, but retains the previously set speed in the ECM memory. A third press of
the switch switches off the whole cruise control system.
Accelerate/Decelerate (+/–) Switches
When the cruise control system is active, pressing the '+' switch set the controlled speed to the current road speed of
the vehicle. Subsequent momentary presses of the switch increase the set road speed by 0.6 mph (1 km/h) with each
press. If the switch is pressed and held the road speed will continue to increase until the switch is released.
M18 0794
1
2
3
4
5
ENGINE MANAGEMENT SYSTEM – TD6
DESCRIPTION AND OPERATION 18-1-43
Momentarily pressing the '–' switch, decreases the set speed by 0.6 mph (1 km/h) with each press. If the switch is
pressed and held, the set speed is decreased until the switch is released.
Resume Switch
The resume switch re-activates the previously set speed after the cruise control has been suspended by pressing the
suspend switch or by depressing the brake pedal.
ENGINE MANAGEMENT SYSTEM – TD6
18-1-44 DESCRIPTION AND OPERATION
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-1
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ENGINE MANAGEMENT SYSTEM – V8DESCRIPTION AND OPERATION
ENGINE MANAGEMENT SYSTEM – V8
18-2-2 DESCRIPTION AND OPERATION
Engine Management Component
Location – Sheet 1 of 2
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-3
1 ECM
2 Variable Camshaft Control (VCC) solenoid
3 Knock sensor (x4)
4 Heated thermostat
5 Mass air flow sensor/Inlet air temperature
(MAF/IAT)
6 Crankshaft Position (CKP) sensor
7 Electric throttle
8 Main relay
ENGINE MANAGEMENT SYSTEM – V8
18-2-4 DESCRIPTION AND OPERATION
Engine Management Component
Location – Sheet 2 of 2
M18 0797
1
2
3
4
5
6
11
12
13
8
9
10
14
7
7
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-5
1 Radiator outlet temperature sensor
2 Engine Coolant Temperature (ECT) sensor
3 Ignition coil
4 Injector
5 Spark plug
6 Purge valve
7 Oxygen sensors
8 Instrument pack
9 Diagnostic socket
10 Accelerator Pedal Position (APP) sensor
11 Camshaft Position (CMP) sensor
12 E-box temperature sensor
13 EAT ECU
14 E-box
ENGINE MANAGEMENT SYSTEM – V8
18-2-6 DESCRIPTION AND OPERATION
Engine Management Control Diagram –
Sheet 1 of 2
A = Hardwired connection; D = CAN bus; J = Diagnostic ISO 9141 K line bus
M18 0805A
D
A
1
2
5
4
3
6
7
9
10
11
12
13
15
17
16
14
19
20
21
22
18
J
8
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-7
1 Accelerator pedal position sensor
2 Instrument pack
3 Radiator outlet coolant temperature sensor
4 Ignition warning lamp
5 Steering angle sensor
6 Alternator
7 DSC/ABS modulator/ECU
8 Diagnostic socket
9 EAT ECU
10 Electric cooling fan
11 Starter motor
12 Immobilisation ECU
13 Oxygen sensors
14 Comfort start relay
15 Secondary air injection pump
16 Vacuum vent valve
17 Secondary air injection pump relay
18 ECM
19 Variable valve control (VCC) solenoid
20 Variable valve control (VCC) solenoid
21 Brake light switch
22 Cruise control switches
ENGINE MANAGEMENT SYSTEM – V8
18-2-8 DESCRIPTION AND OPERATION
Engine Management Control Diagram –
Sheet 2 of 2
A = Hardwired connection
M18 0825
A
1
22
3
4
6
5
8
9
10
11
12
15
16
19
20
18
7
13
14
17
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-9
1 MAF/IAT sensor
2 Camshaft sensor
3 Immobilisation ECU
4 Injector
5 Auxiliary cooling fan relay
6 Purge valve
7 Crankshaft Position (CKP) sensor
8 Fuse 25
9 Main relay
10 Ignition switch
11 Fuel pump
12 Ignition coil relay
13 Fuel pump relay
14 Ignition coil
15 Tank leakage detection module
16 Electric throttle
17 Radiator outlet temperature sensor
18 ECM
19 Electrical heated thermostat
20 Knock sensors
ENGINE MANAGEMENT SYSTEM – V8
18-2-10 DESCRIPTION AND OPERATION
Bosch ME 7.2 Engine Management
System
Introduction
The V8 engine used in New Range Rover is controlled by the Bosch ME 7.2 engine management system (EMS). This
system is similar to the Bosch 5.2.1 system used in previous Land Rover V8 engines. The main difference between
the two systems is the “drive by wire” capabilities of the Me 7.2 EMS.
Another main difference between the 5.2.1 system and the ME 7.2 system is that ME 7.2 uses the Keyword protocol
2000* (KWP2000*) which is a ISO 9141 K Line compatible version of the Key Word 2000 protocol.
General
The key functions of the Bosch ME 7.2 engine management system are:
l To control the amount of fuel supplied to each cylinder
l To calculate and control the exact point of fuel injection
l To calculate and control the exact point of ignition in each cylinder
l To optimise adjustment of the injection timing and ignition timing to deliver the maximum engine performance
throughout all engine speed and load conditions
l To calculate and maintain the desired air/fuel ratio, to ensure the 3 way catalysts operate at their maximum
efficiency
l To maintain full idle speed control of the engine
l To ensure the vehicle adheres to the emission standards (set at the time of homologation)
l To ensure the vehicle meets with the fault handling requirements, as detailed in the European On-Board
Diagnostic (EOBD) III legislation
l To provide an interface with other electrical systems on the vehicle
l To facilitate the drive by wire functions
l To control the Variable Camshaft Control (VCC).
To deliver these key functions, the Bosch ME 7.2 Engine Control Module (ECM) relies upon a number of inputs and
controls a number of outputs. As with all electronic control units, the ECM needs information regarding the current
operating conditions of the engine and other related systems before it can make calculations, which determine the
appropriate outputs. A Controller Area Network (CAN) bus is used to exchange information between the ECM and the
Electronic Automatic Transmission (EAT) ECU
ECM
ECM
The ECM is located in the Environmental (E) box, in the front right corner of the engine compartment. The E-box
provides a protective environment for the ECM and is cooled by an electric fan. The main relay for the ECM is also
located in the E-box.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-11
E-Box
1 Fuse block
2 Cooling fan
3 Main relay
4 ECM
5 E Box temperature sensor
6 EAT ECU
A separate temperature sensor is used to monitor E-box temperature and provides a path to earth to control the
electric fan. The sensor turns the fan on when the E-box temperature reaches 35°C and turns the fan off when the
temperature drops below 35°C. The E-box fan draws air in from the passenger compartment, into the E-box and vents
back into the passenger compartment. The fan is also driven for a short period on engine crank, independently of
temperature. This is done to ensure the correct function of the fan.
The ECM is programmed during manufacture by writing the program and the engine tune into a Flash Electronic
Erasable Programmable Read Only Memory (EEPROM). The EEPROM can be reprogrammed in service using
TestBook/T4. In certain circumstances, it is possible to alter the tune or functionality of the ECM using this process.
ENGINE MANAGEMENT SYSTEM – V8
18-2-12 DESCRIPTION AND OPERATION
Advanced fault monitoring is incorporated into the ECM. It can detect the type and severity of faults, store relevant
engine operating conditions (environmental and freeze frame data) and time that a fault occurs, suspend the operation
of some functions and replace the inputs from faulty sensors with default values. Environmental data is stored for each
fault detected, and consists of the inputs from three engine sensors, with the inputs stored depending on the fault.
The ECM also records additional data in connection with each fault, as follows:
l The number of occurrences
l If the fault is currently present
l If the fault is historic, the number of drive cycles that have elapsed since the fault last occurred
l The time the fault occurred. Time is incremented in hours, hour 0 being the first time the ECM is powered-up,
hour 1 being 60 minutes of ignition 'on' time, etc.
OBD freeze frame data is only stored for emissions related faults. Only one set of freeze frame data can be stored at
any one time. Faults are prioritised according to their likely impact on exhaust gas emissions. If more than one
emissions related fault occurs, freeze frame data is stored for the fault with the highest priority. Freeze frame data
consists of the following:
l Engine speed
l Engine load
l Short term fuelling trim of LH and RH cylinder banks
l Long term fuelling trim of LH and RH cylinder banks
l Fuelling status of LH and RH cylinder banks
l Engine coolant temperature
l Road speed.
Fault information is stored in a volatile Random Access Memory (RAM) in the ECM, so will be deleted if a power failure
or battery disconnection occurs.
Five electrical connectors provide the interface between the ECM and the engine/vehicle wiring. The five connectors
interlock with each other when installed in the ECM. Adjacent connectors should be disconnected in turn. The
installation sequence is the reverse of removal. Each connector groups associated pins together.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-13
ECM Harness Connector C0331 Pin Details
ECM Harness Connector C0332 Pin Details
Pin No. Description Input/Output
1 Alternator warning lamp Output
2 Engine cranking signal Output
3 SAI pump relay Output
4 Cooling fan control unit Output
5 Not used –
6 Engine cranking signal Input
7 APP sensor 1 ground –
8 APP sensor 1 signal Input
9 APP sensor 1 supply Output
10 Fuel pump relay Output
11 Not used –
12 APP sensor 2 ground –
13 APP sensor 2 signal Input
14 APP sensor 2 supply Output
15 and 16 Not used –
17 Diagnostic socket ground –
18 Not used –
19 Reverse gear signal Output
20 Not used –
21 LCM
22 Road speed signal Input
23 Not used –
24 Brake pedal switch Input
25 Not used –
26 Ignition power supply Input
27 Steering wheel cruise control switches Input
28 Brake pedal switch –
29 A/C compressor clutch disengage signal Output
30 and 31 Not used –
32 Diagnostic ISO 9141 K line bus Input/Output
33 Immobilisation signal Input/Output
34 and 35 Not used –
36 CAN bus high (connection with main bus system) Input/Output
37 CAN bus low (connection with main bus system) Input/Output
38 Thermostat monitoring sensor ground –
39 Thermostat monitoring signal Input
40 Starter motor relay Output
Pin No. Description Input/Output
1 Ignition coil 7 Output
2 Ignition coil 8 Output
3 Ignition coil 2 Output
4 Ignition coil 3 Output
5 Ignition ground –
6 Ignition coil 1 Output
7 Ignition coil 4 Output
8 Ignition coil 5 Output
9 Ignition coil 6 Output
ENGINE MANAGEMENT SYSTEM – V8
18-2-14 DESCRIPTION AND OPERATION
ECM Harness Connector C0603 Pin Details
ECM Harness Connector C0604 Pin Details
ECM Harness Connector C0606 Pin Details
Pin No. Description Input/Output
1 to 3 Not used –
4Ground –
5Ground –
6Ground –
7 Not used –
8 Permanent battery power supply Input
9 Not used –
Pin No. Description Input/Output
1 RH rear HO2S heater Output
2 Not used –
3 CAN bus low (connection with EAT ECU) Input/Output
4 CAN bus high (connection with EAT ECU) Input/Output
5 and 6 Not used –
7 LH rear HO2S heater Outer
8 RH rear HO2S ground –
9 LH front HO2S ground –
10 RH front HO2S ground –
11 LH rear HO2S ground –
12 Not used –
13 RH front HO2S heater Output
14 RH rear HO2S signal Input
15 LH front HO2S signal Input
16 RH front HO2S signal Input
17 LH rear HO2S signal Input
18 Not used –
19 LH front HO2S heater Output
20 to 22 Not used –
23 Main relay coil Output
24 Not used –
Pin No. Description Input/Output
1 Fuel injector 2 Output
2 Fuel injector 3 Output
3 EVAP purge valve Output
4 and 5 Not used –
6Ground –
7 MAF/IAT sensor power supply Output
8 Throttle position sensor 2 signal Input
9 MAF/IAT sensor ground –
10 Throttle position sensors reference voltage Output
11 Not used –
12 Starter motor feedback Input
13 Alternator charge signal Input
14 Fuel injector 7 Output
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-15
15 Fuel injector 6 Output
16 VCC solenoid valve 2 Output
17 Not used –
18 CMP sensor signal 2 Input
19 Not used –
20 CMP sensor signal 1 Input
21 ECT sensor ground –
22 ECT sensor signal Input
23 MAF/IAT sensor air flow signal Input
24 Throttle position sensor 1 signal –
25 Throttle position sensor ground –
26 Not used –
27 Fuel injector 8 Output
28 Fuel injector 5 Output
29 VCC solenoid valve 1 Output
30 Not used –
31 Electric thermostat heater Output
32 CKP sensor signal Input
33 Not used –
34 MAF/IAT sensor air temperature signal Input
35 Knock sensor cylinders 3 and 4 ground –
36 Knock sensor cylinders 3 and 4 signal Input
37 Knock sensor cylinders 7 and 8 signal Input
38 Knock sensor cylinders 7 and 8 ground –
39 Not used –
40 Fuel injector 4 Output
41 Fuel injector 1 Output
42 Throttle position actuator 1 Output
43 Throttle position actuator 2 Output
44 Not used –
45 CKP sensor ground –
46 CKP sensor signal Input
47 Not used –
48 Knock sensor cylinders 1 and 2 ground –
49 Knock sensor cylinders 1 and 2 signal Input
50 Knock sensor cylinders 5 and 6 signal Input
51 Knock sensor cylinders 5 and 6 ground –
52 SAI vacuum solenoid valve Output
Pin No. Description Input/Output
ENGINE MANAGEMENT SYSTEM – V8
18-2-16 DESCRIPTION AND OPERATION
System Inputs
The ECM optimises engine performance by interpreting signals from numerous vehicle sensors and other inputs.
Some of these signals are produced by the actions of the driver, some are supplied by sensors located on and around
the engine and some are supplied by other vehicle systems. The inputs are as follows:
l Ignition switch
l Accelerator pedal position sensor (APP)
l Throttle position feedback
l Crankshaft Position (CKP) sensor
l Cruise control signal (from steering wheel switch pack)
l Brake light switch
l Camshaft Position (CMP) sensors
l Engine Coolant Temperature (ECT) sensor
l Knock sensors
l Air Mass/Intake Air Temperature (MAF/IAT) sensor
l Heated Oxygen Sensors (HO2S)
l Immobilisation signal (from immobilisation ECU)
l Fuel level signal (via CAN)
l Vehicle speed signal (from ABS ECU)
l Radiator outlet temperature sensor
l Internal ambient barometric pressure sensor (altitude sensor)
l Electronic Automatic Transmission (EAT) information.
Electric Throttle System
The EMS incorporates an electric throttle control system. This system comprises three main components:
l Electronic throttle control valve
l Accelerator pedal position sensor (APP)
l ECM.
When the accelerator pedal is depressed the APP sensor provides a change in the monitored signals. The ECM
compares this against an electronic “map” and moves the electronic throttle valve via a pulse width modulated control
signal which is in proportion to the APP angle signal.
The system is required to:
l Regulate the calculated intake air load based on the accelerator pedal sensor input signals and programmed
mapping
l Monitor the drivers input request for cruise control operation
l Automatically position the electronic throttle for accurate cruise control
l Perform all dynamic stability control throttle control interventions
l Monitor and carry out maximum engine and road speed cut out.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-17
Accelerator Pedal Position (APP) Sensor
1 Detente mechanism
2 Sensor spigot
3 Pedal
4 Springs
5 Cables
6 Bush
7 Drum
8 APP sensor
The APP sensor is located in a plastic housing which is integral with the throttle pedal. The housing is injection
moulded and provides location for the APP sensor. The sensor is mounted externally on the housing and is secured
with two Torx screws. The external body of the sensor has a six pin connector which accepts a connector on the
vehicle wiring harness.
The sensor has a spigot which protrudes into the housing and provides the pivot point for the pedal mechanism. The
spigot has a slot which allows for a pin, which is attached to the sensor potentiometers, to rotate through
approximately 90°, which relates to pedal movement. The pedal is connected via a link to a drum, which engages with
the sensor pin, changing the linear movement of the pedal into rotary movement of the drum. The drum has two steel
cables attached to it. The cables are secured to two tension springs which are secured in the opposite end of the
housing. The springs provide 'feel' on the pedal movement and require an effort from the driver similar to that of a
cable controlled throttle. A detente mechanism is located at the forward end of the housing and is operated by a ball
located on the drum. At near maximum throttle pedal movement, the ball contacts the detente mechanism. A spring
in the mechanism is compressed and gives the driver the feeling of depressing a 'kickdown' switch when full pedal
travel is achieved.
ENGINE MANAGEMENT SYSTEM – V8
18-2-18 DESCRIPTION AND OPERATION
APP Sensor Output Graph
A = Voltage
B = APP sensor angle
C = Kick down angle
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-19
The APP sensor has two potentiometer tracks which each receive a 5V input voltage from the ECM. Track 1 provides
an output of 0.5V with the pedal at rest and 2.0V at 100% full throttle. Track 2 provides an output of 0.5V with the
pedal at rest and 4.5V at 100% full throttle. The signals from the two tracks are used by the ECM to determine fuelling
for engine operation and also by the ECM and the EAT ECU to initiate a kickdown request for the automatic
transmission.
The ECM monitors the outputs from each of the potentiometer tracks and can determine the position, rate of change
and direction of movement of the throttle pedal. The 'closed throttle' position signal is used by the ECM to initiate idle
speed control and also overrun fuel cut-off.
Electric Throttle
Electric Throttle Control Valve
The Electric Throttle control valve is controlled by the APP sensor via the ECM. The throttle valve plate is positioned
by gear reduction DC motor drive. The DC motor is controlled by a proportionally switched high/low PWM signals at
a basic frequency of 2000Hz. Engine idle speed control is a function of the Electric Throttle control valve, therefore a
separate idle control valve is not required.
The electric throttle control valve throttle plate position is monitored by two integrated potentiometers. The
potentiometers provide DC voltage feedback signals to the ECM for throttle and idle control functions.
Potentiometer one is used as a the primary signal, potentiometer two is used as a plausibility check through the total
range of throttle plate movement.
If the ECM detects a plausibility error between Pot 1 and Pot 2 it will calculate the inducted air mass from the air mass
(from the air mass sensor) and only utilise the potentiometer signal which closely matches the detected intake air
mass. It does this to provide a fail-safe operation by using a 'virtual' potentiometer as a comparative source.
If the ECM cannot calculate a plausible value from the monitored potentiometers (1 and 2) the throttle motor is
switched off and the fuel injection cut out is activated.
The electric throttle control valve is continuously monitored during operation. It is also briefly activated when the
ignition switch is initially turned to position II. This is done to check the valves mechanical integrity by monitoring the
motor control amperage and the reaction speed of the feedback potentiometers.
Should the electronic throttle need replacing the adaption values of the previous unit will need to be cleared from the
ECM. This is achieved by the following process:
1 Using TestBook/T4 clear the adaption values
2 Switch the ignition “OFF” for 10 seconds
3 Switch the ignition “ON”, for approximately 30 seconds the electric throttle control valve is briefly activated
allowing the ECM to learn the new component.
This procedure is also necessary after the ECM has been replaced. However the adaption values do not require
clearing since they have not yet been established.
ENGINE MANAGEMENT SYSTEM – V8
18-2-20 DESCRIPTION AND OPERATION
Crankshaft Position (CKP) Sensor
The CKP sensor is located in the lower right side of the transmission bell housing, in line with the engine flywheel.
The sensor reacts to a reluctor ring to ascertain engine speed and position information. The sensor has three wires
attached to it; two signal wires and a sensor earth screen. The sensor earth screen is connected to chassis earth
through the ECM.
CKP Sensor
The CKP sensor is an inductive type sensor which produces a sinusoidal output voltage signal. This voltage is induced
by the proximity of the moving reluctor ring, which excites the magnetic flux around the tip of the sensor when each
tooth passes. This output voltage will increase in magnitude and frequency as the engine speed rises and the speed
at which the teeth on the reluctor ring pass the sensor increases. The signal voltage will peak at approximately 6.5
volts if connected to the ECM (further increases in engine speed will not result in greater magnitude). The ECM neither
specifically monitors nor reacts to the output voltage (unless it is very small or very large), instead it measures the
time intervals between each pulse (i.e. signal frequency). The signal is determined by the number of teeth passing
the sensor, and the speed at which they pass. The reluctor ring has 58 teeth spaced at 6° intervals, with two teeth
missing to give the ECM a synchronisation point.
The signal produced by the CKP sensor is critical to engine running. There is no back-up strategy for this sensor and
failure of the signal will result in the engine stalling and/or failing to start. If the sensor fails when the engine is running,
then the engine will stall, a fault code will be stored and details captured of the battery voltage, engine coolant
temperature and intake air temperature at the time of the failure. If the signal fails when the engine is cranking, then
the engine will not start and no fault will be stored, as the ECM will not detect that an attempt had been made to start
the engine. In both cases the tachometer will also cease to function immediately and the MIL lamp will be permanently
illuminated.
During the power-down procedure, which occurs when the ignition is switched off, the ECM stores details of the
position of the CKP and CMP sensors. This enables the ECM to operate the injectors in the correct sequence
immediately the engine cranks, to produce a quick engine start, which serves to reduce emissions when the engine
is cold.
Camshaft Position (CMP) Sensor
There are two CMP sensors which are located on the upper timing case covers. The CMP sensors monitor the
position of the camshafts to establish ignition timing order, fuel injection triggering and for accurate Variable Camshaft
Control (VCC) camshaft advance-retard timing feedback. The CMP sensor is a Hall-effect sensor which switches a
battery fed supply on and off. The supply is switched when the teeth machined onto the camshaft gear pass by the
tip of the sensor. The four teeth are of differing shapes, so the ECM can determine the exact position of the camshaft
at any time.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-21
CMP Sensor
Unlike an inductive type sensor, a Hall-effect sensor does not produce a sinusoidal output voltage (sine wave).
Instead it produces a square wave output. The wave edges are very sharp, giving the ECM a defined edge on which
to base its calculations.
An implausible signal from the CMP sensor will result in the following:
l The MIL lamp illuminated after de-bouncing the fault (NAS only and EU)
l Loss of performance, due to the corrective ignition strategy being disabled. A default ignition map is used which
retards the timing to a safe position
l Injector operation possibly 360° out of phase, i.e. fuel injected during exhaust stroke rather than during
compression stroke
l Quick crank/cam synchronisation on start-up feature disabled
l Some Oxygen sensor diagnostics disabled.
In addition, the ECM will store a relevant fault code and capture the input signal supplied by the engine coolant
temperature sensor, the engine load calculation and the engine speed at the time of failure. TestBook/T4 will display
the live readings from the CMP sensor.
Ambient Barometric Pressure Sensor
The ECM incorporates an integral ambient barometric pressure sensor. This internal sensor is supplied with a 5V feed
and returns a linear voltage of between 2.4 and 4.5 Volts. This represents the barometric pressure.
The system monitors barometric pressure for the following reasons:
l The barometric pressure along with the calculated air mass provides additional correction for refining injection
“ON” time
l The value provides a base value for the ECM to calculate the air mass being injected into the exhaust system by
the secondary air injection system. This correction factor changes the secondary air injection “ON” time which in
turn optimises the necessary air flow into the exhaust system
l The signal is used to recognise down hill driving to postpone the start of evaporative emission leakage diagnosis.
ENGINE MANAGEMENT SYSTEM – V8
18-2-22 DESCRIPTION AND OPERATION
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is located front of the engine, adjacent to the thermostat housing. The sensor incorporates two
Negative Temperature Coefficient (NTC) thermistors and four electrical connections. One set of connections are used
by the ECM while the other set are used by the instrument pack temperature gauge.
ECT Sensor
Each thermistor used forms part of a voltage divider circuit operating with a regulated 5 V feed and an earth.
The signal supplied by the ECT sensor is critical to many fuel and ignition control strategies. Therefore, the ECM
incorporates a complex ECT sensor default strategy, which it implements in the event of failure. The ECM uses a
software model, based on the time the engine has been running and the air intake temperature, to provide a changing
default value during the engine warm-up. When the software model calculates the coolant temperature has reached
60 °C, a fixed default value of 85 °C is adopted for the remainder of the ignition cycle. The software model also forms
part of the sensor diagnostics: if there is too great a difference between the temperatures from the sensor input and
the software model, for more than 2.54 seconds, the ECM concludes there is a fault with the sensor input.
The following symptoms may be noticeable in the event of an ECT sensor failure:
l The MIL lamp illuminated
l Poor engine hot and cold start
l Instrument pack engine overheat warning lamp illuminated
l Excessively hot or cold reading on the temperature gauge.
At the time of a failure, the ECM will also store details of the engine speed, engine load and intake air temperature in
its memory. This information is stored to aid diagnosis of the fault.
Knock Sensors
Two knock sensors are located on each cylinder block between the first and second and third and fourth cylinders of
each cylinder bank. The knock sensors produce a voltage signal in proportion to the amount of mechanical vibration
generated at each ignition point. Each sensor monitors two cylinders in the related cylinder bank.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-23
Knock Sensor
The knock sensors incorporate a piezo-ceramic crystal. This crystal produces a voltage whenever an outside force
tries to deflect it, (i.e. exerts a mechanical load on it). When the engine is running, the compression waves in the
material of the cylinder block, caused by the combustion of the fuel/air mixture within the cylinders, deflect the crystal
and produce an output voltage signal. The signals are supplied to the ECM, which compares them with `mapped'
signals stored in memory. From this, the ECM can determine when detonation occurs on individual cylinders. When
detonation is detected, the ECM retards the ignition timing on that cylinder for a number of engine cycles, then
gradually returns it to the original setting.
Care must be taken at all times to avoid damaging the knock sensors, but particularly during removal and fitting
procedures. The recommendations regarding torque and surface preparation must be adhered to. The torque applied
to the sensor and the quality of the surface preparation both have an influence over the transfer of mechanical noise
from the cylinder block to the crystal.
The ECM uses the signals supplied by the knock sensors, in conjunction with the signal it receives from the camshaft
sensor, to determine the optimum ignition point for each cylinder. The ignition point is set according to pre-
programmed ignition maps stored within the ECM. The ECM is programmed to use ignition maps for 95 RON premium
specification fuel. It will also function on 91 RON regular specification fuel but without adaptions. If the only fuel
available is of poor quality, or the customer switches to a lower grade of fuel after using a high grade for a period of
time, the engine may suffer slight pre-ignition for a short period. This amount of pre-ignition will not damage the
engine. This situation will be evident while the ECM learns and then modifies its internal mapping to compensate for
the variation in fuel quality. This feature is called adaption. The ECM has the capability of adapting its fuel and ignition
control outputs in response to several sensor inputs.
The ECM will cancel closed loop control of the ignition system if the signal received from either knock sensor becomes
implausible. In these circumstances the ECM will default to a safe ignition map. This measure ensures the engine will
not become damaged if low quality fuel is used. The MIL lamp will not illuminate, although the driver may notice that
the engine 'pinks' in some driving conditions and displays a slight drop in performance and smoothness.
When a knock sensor fault is stored, the ECM will also store details of the engine speed, engine load and the coolant
temperature.
ENGINE MANAGEMENT SYSTEM – V8
18-2-24 DESCRIPTION AND OPERATION
Mass Air Flow/Air Intake Temperature (MAF/IAT) Sensor
The MAF/IAT sensor is located in the air intake ducting, between the air cleaner and the throttle body. The sensor
outputs intake air flow and temperature signals to the ECM to enable calculation of the mass of the air entering the
engine.
In addition to the air flow and temperature outputs, a regulated 5 V feed and an earth are connected between the
sensor and the ECM, and the sensor receives a battery power feed from the main relay.
Air flow: The air flow signal is produced from a hot film element in the sensor. The film is connected between the 5 V
feed and the air flow output to the ECM. The film is also heated by the battery power feed and cooled by the air flow
into the engine. The greater the air flow, the greater the cooling effect and the lower the electrical resistance across
the sensor. So the air flow output voltage varies with changes in air flow and, from voltage/air flow maps stored in
memory, the ECM determines the mass of air entering the engine.
Air intake temperature: The air intake temperature signal is produced by a NTC thermistor connected between the 5
V feed and earth to complete a voltage divider circuit. The ECM monitors the voltage drop across the thermistor and,
from voltage/temperature maps stored in memory, determines the temperature of the intake air.
The MAF/IAT sensor is sensitive to sudden shocks and changes in its orientation. It should, therefore, be handled
carefully. It is also important that the intake ducting between the air cleaner and the throttle body is not altered in
diameter or modified in any way. The air mass flow meter contains electronic circuitry, so never attempt to supply it
directly from the battery. The terminals have a silver coating to provide a superior quality of connection over many
years. If, at any time, a probe is used to measure the output directly from the sensor, then care must be taken to
ensure this coating is not damaged.
MAF/IAT Sensor
If the air flow signal fails the ECM adopts a default value for air flow volume based on throttle position and engine
speed. The following engine symptoms will be noticeable:
l The engine speed might 'dip' before the default strategy enables continued running
l The engine may be difficult to start and prone to stalling
l The overall performance of the engine will be adversely affected (throttle response in particular)
l Exhaust emissions will be out of tolerance, because the air/fuel ratio value is now assumed, not calculated; no
closed loop fuelling
l Idle speed control disabled, leading to rough idle and possible engine stall.
At the time of failure, the ECM will store details of the engine speed, coolant temperature and throttle angle.
If the intake air temperature signal fails, the ECM adopts a default value of 45 °C. This default value is then used within
all the calculations involving intake air temperature. The effect on the vehicle of a failed air temperature signal will not
be so noticeable to the driver, who may notice a reduction in engine performance when operating the vehicle at high
altitudes or in hot ambient temperatures. The occurrence of this fault will also disable fuelling adaptions.
The ECM will store details of the engine speed, engine load and battery voltage when this fault is first detected.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-25
Heated Oxygen Sensors (HO2S)
The HO2S provide feedback signals to the ECM to enable closed loop control of the Air Fuel Ratio (AFR). Four HO2S
are installed, one pre-catalyst and one post-catalyst per cylinder bank. Each HO2S produces an output voltage which
is inversely proportional to the oxygen content of the exhaust gases.
HO2S
Each HO2S consists of a zirconium sensing element with a gas permeable ceramic coating on the outer surface. The
outer surface of the sensing element is exposed to the exhaust gas and the inner surface is exposed to ambient air.
The difference in the oxygen content of the two gases produces an electrical potential difference across the sensing
element. The voltage produced depends on the differential between the two oxygen contents. When the AFR is
Lambda 1 (i.e. stoichiometric AFR of 14.7:1 by mass) the voltage produced is approximately 450 mV. With a lean
mixture of Lambda 1.2, the higher oxygen content of the exhaust gases results in a voltage of approximately 100 mV.
With a rich mixture of Lambda 0.8, the lower oxygen content of the exhaust gases results in a voltage of approximately
900 mV.
The ECM monitors the effect of altering the injector pulse widths using the information supplied by the two HO2S.
Injector pulse width is the length of time the injector is energised, which determines how much fuel is injected. The
response time is such that under certain driving conditions, the ECM can assess individual cylinder contributions to
the total exhaust emissions. This enables the ECM to adapt the fuelling strategy on a cylinder by cylinder basis, i.e.
inject the precise amount of fuel required by each individual cylinder at any given time.
HO2S Principle of Operation
A = Ambient air; B = Exhaust gases
1 Protective ceramic coating
2 Electrodes
3 Zirconium oxide
M18 0837
V
A
B
2
3
1
ENGINE MANAGEMENT SYSTEM – V8
18-2-26 DESCRIPTION AND OPERATION
HO2S Output
A = Output, mV; B = AFR, lambda
1 Lambda window
2 Lean AFR
3 Rich AFR
The ECM continuously checks the signals supplied by the HO2S for plausibility. If it detects an implausible signal, the
ECM stores a relevant fault code and details of engine speed, engine load and the HO2S signal voltage. The ECM
requires the HO2S signals to set most of its adaptions. Failure of an HO2S results in most of these adaptions resetting
to their default values. This, in turn, results in loss of engine refinement. The engine may exhibit poor idle
characteristics and emit a strong smell of rotten eggs from the exhaust (caused by an increase in hydrogen sulphide).
The efficiency of the HO2S slowly deteriorates with use and must be periodically replaced (currently every 120,000
miles, but refer to the maintenance schedules for the latest service replacement period). The ECM is able to detect
this steady deterioration from the HO2S signals. If a sensor deteriorates beyond a predetermined threshold, the ECM
stores a fault code and captures details of the engine speed, engine load and battery voltage.
The HO2S needs a high operating temperature to work effectively. To ensure a suitable operating temperature is
reached as soon as possible, each sensor incorporates a heating element inside the ceramic tip. This element heats
the HO2S to a temperature greater than 350 °C. The heating rate (the speed at which the temperature rises) is
carefully controlled by the ECM to prevent thermal shock to the ceramic material. The ECM supplies a Pulse Width
Modulated (PWM) supply to the heater elements to control the rate at which the HO2S temperature is increased. The
HO2S are heated during engine warm-up and again after a period of engine idle.
The ECM monitors the state of the heating elements by calculating the amount of current supplied to each sensor
during operation. If the ECM identifies that the resistance of either heating element is too high or too low, it will store
a fault code, the engine speed, coolant temperature and the battery voltage.
HO2S are very sensitive devices. They must be handled carefully at all times. Failure to handle correctly will result in
a very short service life, or non-operation. HO2S are threads coated with an anti-seize compound prior to installation.
Care should be taken to avoid getting this compound on the sensor tip. If the sensor needs to be removed and refitted,
a small amount of anti-seize compound should be applied (see workshop manual for details).
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-27
Radiator Outlet Temperature Sensor
The ECM uses an additional engine coolant temperature sensor located in the radiator outlet. The sensor monitors
the temperature of the coolant leaving the radiator for precise activation of the auxiliary fan. The sensor is an NTC
thermistor type. The signal is used by the ECM to activate the auxiliary fan when the engine coolant temperature
leaving the radiator is in the range of 80°C to 104°C.
Fuel Level Signal
The ECM monitors the contents of the fuel tank as part of the misfire detection strategy. If a misfire occurs while a low
fuel level exists, the ECM stores an additional fault code to indicate that fuel starvation resulting from fuel slosh is a
possible cause of the misfire. On New Range Rover, the low fuel level signal is internally generated by the ECM, from
a CAN signal via the instrument pack.
Vehicle Speed Signal
The ECM receives the vehicle speed signal from the ABS ECU. The ECM uses this signal within its calculations for
idle speed control. The signal is transmitted at 8000 pulses/mile and is the average of the road speed signals from all
four wheel speed sensors. The ABS ECU outputs the vehicle speed signal to the EAT ECU on the CAN bus.
Rough Road Signal
When the vehicle is travelling over a rough road surface the engine crankshaft is subjected to torsional vibrations
caused by mechanical feedback from the road surface through the transmission. To prevent misinterpretation of these
torsional vibrations as a misfire, the ECM calculates a rough road level by monitoring individual wheel speeds from
the ABS ECU on the CAN bus. The ECM determines the quality of the road surface by monitoring a CAN signal from
the ABS ECU, which modulates the duty cycle of the signal in response to variations between ABS sensor inputs.
Misfire monitoring is restored when the quality of the road surface improves again.
If there is a fault with the CAN data, the ECM defaults to permanent misfire monitoring.
A/C Request Signals
Because of the loads imposed on the engine when the air conditioning system operates, the ECM is included in the
control loop for the compressor and the cooling fans. If it becomes necessary to limit or reduce the load on the engine,
the ECM can then prevent or discontinue operation of the air conditioning compressor.
ENGINE MANAGEMENT SYSTEM – V8
18-2-28 DESCRIPTION AND OPERATION
Automatic Gearbox Information
Information sent to and from the EAT ECU is transmitted on the CAN bus.
The ECM requires information on gear position to calculate the likely engine load during acceleration and deceleration
conditions. The ECM also disables the misfire detection function whenever low range is selected. The ECM receives
this information from the transfer box ECU on the CAN Bus.
There are several possible fault codes associated with the CAN bus and the validity of the messages exchanged
between the ECM and the EAT ECU. In most cases, the ECM will store engine speed, engine coolant temperature
and details of the battery voltage at the time a CAN fault is detected.
If the EAT ECU detects a gearbox fault, it requests the ECM to illuminate the MIL in the instrument pack and to store
freeze frame data.
Ignition Switch
The ignition switch signal enables the ECM to detect if the ignition is on or off. The signal is a power feed that is
connected to the ECM while the ignition switch is positions II and III. On the New Range Rover, the power feed comes
from the ignition relay in the engine compartment fuse box.
When it first receives the signal, the ECM 'wakes-up' and initiates a power-up sequence to enable engine starting and
operation. The power-up sequence includes energising the main relay, which supplies the main power feed to the
ECM, energising the fuel pump relay and initiating a self check of the engine management system.
When it detects the ignition has been turned off, the ECM stops activating the fuel injectors and ignition coil, to stop
the engine, and de-energises the fuel pump relay, but keeps the main relay energised while it performs a power down
sequence. During the power down sequence the ECM records the engine sensor values required for a quick-start
function to operate the next time the engine is cranked. At the end of the power down sequence, the ECM de-
energises the main relay to switch itself off.
System Outputs
The ECM receives and processes the input information previously described and modifies the fuelling and the ignition
points for each cylinder accordingly. The ECM will also supply output information to other vehicle systems.
The ECM drives the following components:
l Fuel injectors
l Ignition coils
l Main relay and fuel pump relay
l Tank Leakage Detection (NAS)
l Secondary Air Injection Pump
l Secondary Air Injection valve
l VCC Valves
l Electrically heated thermostat
l Air conditioning compressor (relay drive).
The ECM provides other systems with information regarding the:
l Engine speed
l Driver demand
l ATC request
l Automatic Transmission
l Fuel used
l Auxiliary cooling fan.
Ignition Coils
The ME 7.2 EMS utilises plug top coils which are mounted directly on top of the spark plug.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-29
Ignition Coils
Ignition related faults are indirectly monitored via misfire detection. The are no specific checks of the primary circuits.
Fuel Injectors
An electromagnetic, top feed fuel injector is installed in each cylinder inlet tract of the inlet manifolds. A common fuel
rail supplies the injectors with fuel from a returnless fuel delivery system. The fuel in the fuel rail is maintained at 3.5
bar above inlet manifold pressure by a pressure regulator incorporated into the fuel filter. A Schraeder valve is
installed in the fuel rail, to the rear of injector No. 7, to enable the fuel pressure to be checked.
Fuel Rail and Injectors
Each injector contains a solenoid operated needle valve which is closed while the solenoid winding is de-energised.
The solenoid winding is connected to a power feed from the main relay and to an earth through the ECM. The ECM
switches the earth to control the opening and closing of the needle valve (injector 'firing'). While the needle valve is
open, fuel is sprayed into the cylinder inlet tract onto the back of the inlet valves. The ECM meters the amount of fuel
injected by adjusting the time that the needle valve is open (injector pulse width).
Each injector is sealed with two 'O' rings, which should be renewed whenever an injector is refitted to an engine. A
small amount of engine oil can be applied to the 'O' rings to aid installation. No other form of lubrication should be
used.
ENGINE MANAGEMENT SYSTEM – V8
18-2-30 DESCRIPTION AND OPERATION
Fuel Injector
Measuring the electrical resistance of the solenoid winding enables an assessment to be made of the serviceability
of an injector. Nominal resistance of the solenoid winding is 14.5 ± 0.7 Ω at 20 °C.
The ECM can detect electrical inconsistencies within each injector. It can also detect, via feedback from the HO2S,
mechanical faults such as blockage or leakage. The ECM will store a relevant fault code in these circumstances. The
ECM will also store the engine speed, engine load and details of either the battery voltage, engine coolant
temperature or intake air temperature. The precise details stored depend on the exact nature of the fault detected.
T4 will also display data regarding injector operation via its live readings. Care must be taken when analysing this
data, as the precise timings will vary considerably. Individual timings will be affected by any current engine load.
Main Relay
The ECM controls its own power supply, via the main relay in the engine compartment fusebox. When the ignition is
turned to position II, the ECM provides a ground to the main relay coil. The main relay then energises and connects
the main power feed to the ECM. The ECM controls the main relay, and therefore its own power supply, so that when
the ignition is turned off it can follow the power-down sequence, during which it records values from various sensors
and writes adaptions into its memory, etc. The last action the ECM carries out before completing its power-down
sequence is to turn off the main relay. This will occur approximately 7 seconds after the ignition has been switched
off, as long as the coolant temperature is not rising. For NAS vehicle with tank leakage detection and under some
vehicle system fault conditions, this period could be extended up to 20 minutes.
Failure of the main relay will result in the engine failing to start. The engine will stop immediately if the main relay fails
while the engine is running.
Fuel Pump Relay
The ECM controls operation of the fuel pump via the fuel pump relay in the rear fusebox. The ECM switches the relay
coil to earth to energise the relay when the ignition is first turned to position II. The relay remains energised during
engine cranking and while the engine is running, but will be de-energised after approximately 2 seconds if the ignition
switch remains in position II without the engine running.
A fuel cut-off function is incorporated into the ECM to de-energise the fuel pump in a collision. The cut off function is
activated by a signal from the SRS DCU in the event of an airbag activation. The ECM receives an airbag activation
signal from the SRS DCU on the CAN Bus.
The fuel cut-off function can only be reset by using TestBook/T4.
The ECM monitors the state of the wiring to the coil winding within the fuel pump relay. The ECM will store relevant
fault codes if the ECM detects a problem. The ECM is not able to assess the state of the fuel pump circuit because it
is isolated by the function of the relay. However, if the fuel pump circuit fails, or the pump fails to deliver sufficient fuel
(while the fuel level is above the minimum level), the ECM will store adaptive faults as it tries to increase the air/fuel
ratio by increasing the pulse width of the injectors.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-31
Failure of the fuel pump relay will result in the engine failing to start. If the fuel pump fails while the engine is running,
the symptoms will be engine hesitation and engine misfire. These symptoms will worsen progressively until the engine
stops. The ECM will store several fault codes under this condition.
Electrically Heated Thermostat
The electrically heated thermostat is used to regulate the engine coolant temperature. The thermostat regulates the
coolant temperature depending upon engine load and vehicle speed. This allows the engine coolant temperature to
be raised when the engine is operating at part load. Raising the coolant temperature while the engine is at part load
has a beneficial effect on fuel consumption and emissions.
If a conventional thermostat with higher constant operating temperature is used, poor response when accelerating
and in traffic could result.
The thermostat is controlled by the ECM is response to engine load against a 'map' stored within the ECM.
The map is based upon the following inputs:
l Engine load
l Engine speed
l Vehicle speed
l Intake air temperature
l Coolant temperature.
The thermostat unit is a one piece construction comprising the thermostat, thermostat housing and heater element.
The housing is of a die-cast aluminium. The electrical connection for the heater element is housed in the body. The
heater element is an expanding (wax) element.
Heated Thermostat
The thermostat is set to open when the coolant temperature reaches 103°C at the thermostat. Once the coolant has
passed through the engine its temperature is approximately 110°C at the engine temperature sensor.
If the ECM starts to regulate the system the ECM supplies an earth path for the heater element in the thermostat. This
causes the element to expand and increase the opening dimension of the thermostat.
The warmer the element the sooner the thermostat opens and the lower the resulting coolant temperature is. The
thermostat regulates the coolant temperature in the range 80°C to 103°C. The expanding element in the thermostat
is heated to a higher temperature than the surrounding coolant to generate the correct opening aperture. Should the
coolant temperature exceed 113°C the electrically heated thermostat is activated independently of the prevailing
engine parameters.
Should the heated thermostat fail, (fault codes will be stored in the ECM) the EMS will ensure the safe operation of
the engine and the thermostat will operate as a conventional unit.
ENGINE MANAGEMENT SYSTEM – V8
18-2-32 DESCRIPTION AND OPERATION
ECM Adaptions
The ECM has the ability to adapt the values it uses to control certain outputs. This capability ensures the EMS can
meet emissions legislation and improve the refinement of the engine throughout its operating range.
The components which have adaptions associated with them are:
l The IACV
l The APP sensor
l The HO2S
l The MAF/IAT sensor
l The CKP sensor
l Electric throttle body.
HO2S and MAF/IAT Sensor
There are several adaptive maps associated with the fuelling strategy. Within the fuelling strategy the ECM calculates
short-term adaptions and long term adaptions. The ECM will monitor the deterioration of the HO2S over a period of
time. It will also monitor the current correction associated with the sensors.
The ECM will store a fault code in circumstances where an adaption is forced to exceed its operating parameters. At
the same time, the ECM will record the engine speed, engine load and intake air temperature.
CKP Sensor
The characteristics of the signal supplied by the CKP sensor are learned by the ECM. This enables the ECM to set
an adaption and support the engine misfire detection function. Due to the small variation between different flywheels
and different CKP sensors, the adaption must be reset if either component is renewed, or removed and refitted. It is
also necessary to reset the flywheel adaption if the ECM is renewed or replaced.
The ECM supports four flywheel adaptions for the CKP sensor. Each adaption relates to a specific engine speed
range. The engine speed ranges are detailed in the table below:
To set the flywheel adaptions, follow the procedure detailed below. This procedure should be carried out in an
appropriate area off the public highway. TestBook/T4 must be connected throughout this procedure. The adaptive
speed settings must be read from TestBook/T4 while the vehicle is moving at speed.
1 Use TestBook/T4 to clear any adaptions currently set.
2 With the engine warm (>86 °C), select 2nd gear high range.
3 Accelerate the vehicle until the engine speed reaches the limiter.
4 Release the throttle and allow the vehicle to decelerate until the engine idle speed is reached.
5 Check that one of the speed range adaptions has been set (read this from TestBook/T4).
6 Repeat the above procedure until all four adaptions are set
When all four adaptions have been set, check that the ECM has not recorded any misfire detection faults. If it has,
then clear the memory of the misfire fault codes.
It may not be possible to reset adaption number 4 if the ECM has already been programmed with a value. Due to the
nature of the procedure and the self learn capacity of the ECM, if adaption number 4 does not reset, it is permissible
to leave this adaption and let the ECM learn it during normal vehicle usage.
Misfire Detection
Legislation requires that the ECM must be able to detect the presence of an engine misfire. It must be able to detect
misfires at two separate levels. The first level is a misfire that could lead to the vehicle emissions exceeding 1.5 times
the Federal Test Procedure (FTP) requirements for the engine. The second level is a misfire that may cause catalyst
damage.
Adaptation Engine Speed, rev/min
1 1800 - 3000
2 3001 - 3800
3 3801 - 4600
4 4601 - 5400
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-33
The ECM monitors the number of misfire occurrences within two engine speed ranges. If the ECM detects more than
a predetermined number of misfire occurrences within either of these two ranges, over two consecutive journeys, the
ECM will record a fault code and details of the engine speed, engine load and engine coolant temperature. In addition,
the ECM monitors the number of misfire occurrences that happen in a 'window' of 200 engine revolutions. The misfire
occurrences are assigned a weighting according to their likely impact on the catalysts. If the number of misfires
exceeds a certain value, the ECM stores catalyst-damaging fault codes, along with the engine speed, engine load
and engine coolant temperature.
The signal from the crankshaft position sensor indicates how fast the poles on the flywheel are passing the sensor
tip. A sine wave is generated each time a pole passes the sensor tip. The ECM can detect variations in flywheel speed
by monitoring the sine wave signal supplied by the crankshaft position sensor.
By assessing this signal, the ECM can detect the presence of an engine misfire. At this time, the ECM will assess the
amount of variation in the signal received from the crankshaft position sensor and assigns a roughness value to it.
This roughness value can be viewed within the real time monitoring feature, using TestBook/T4. The ECM will
evaluate the signal against a number of factors and will decide whether to count the occurrence or ignore it. The ECM
can assign a roughness and misfire signal for each cylinder, (i.e. identify which cylinder is misfiring).
TestBook/T4 Diagnostics
The ECM stores faults as Diagnostic Trouble Codes (DTC), referred to as 'P' codes. The 'P' codes are defined by
OBD legislation and, together with their associated environmental and freeze frame data, can be read using a third
party scan tool or TestBook/T4. TestBook/T4 can also read real time data from each sensor, the adaptive values
currently being employed and the current fuelling, ignition and idle settings.
ENGINE MANAGEMENT SYSTEM – V8
18-2-34 DESCRIPTION AND OPERATION
Engine Management P Codes
P Code No. Component/Signal Fault Description
0010 LH bank CMP sensor Signal malfunction
0011 LH bank CMP sensor Timing over-advanced or system
performance
0012 LH bank CMP sensor Timing over-retarded
0020 RH bank CMP sensor Signal malfunction
0021 RH bank CMP sensor Timing over-advanced or system
performance
0022 RH bank CMP sensor Timing over-retarded
0030 LH bank front HO2S heater circuit Circuit intermittent
0031 LH bank front HO2S heater circuit Short circuit to ground
0032 LH bank front HO2S heater circuit Short circuit to battery
0036 LH bank rear HO2S heater circuit Circuit intermittent
0037 LH bank rear HO2S heater circuit Short circuit to ground
0038 LH bank rear HO2S heater circuit Short circuit to battery
0050 RH bank front HO2S heater circuit Circuit intermittent
0051 RH bank front HO2S heater circuit Short circuit to ground
0052 RH bank front HO2S heater circuit Short circuit to battery
0056 RH bank rear HO2S heater circuit Circuit intermittent
0057 RH bank rear HO2S heater circuit Short circuit to ground
0058 RH bank rear HO2S heater circuit Short circuit to battery
0102 MAF sensor signal Short circuit to ground
0103 MAF sensor signal Short circuit to battery
0106 ECM internal ambient pressure sensor Performance problem
0107 ECM internal ambient pressure Short circuit to ground
0108 ECM internal ambient pressure Open circuit or short circuit to battery
0112 IAT sensor Short circuit to ground
0113 IAT sensor Open circuit or short circuit to battery
0114 Ambient temperature input Fault data received
0116 ECT sensor Signal implausible
0117 ECT sensor Short circuit to ground
0118 ECT sensor Open circuit or short circuit to battery
0120 APP sensor switch A Implausible
0121 APP sensor switch A Range/ Performance problem
0122 APP sensor switch A Open circuit or short circuit to ground
0123 APP sensor switch A Short circuit to battery
0125 ECT sensor Insufficient coolant temperature for
closed loop control
0128 Thermostat monitoring sensor Low coolant temperature – thermostat
stuck open
0130 LH bank front HO2S signal Circuit malfunction
0131 LH bank front HO2S signal Short circuit to ground
0132 LH bank front HO2S signal Short circuit to battery
0133 LH bank front HO2S signal Slow response
0134 LH bank front HO2S signal No activity
0135 LH bank front HO2S heater circuit Circuit malfunction
0136 LH bank rear HO2S signal Circuit malfunction
0137 LH bank rear HO2S signal Short circuit to ground
0138 LH bank rear HO2S signal Short circuit to battery
0139 LH bank rear HO2S signal Slow response
0140 LH bank rear HO2S signal No activity
0141 LH bank rear HO2S heater circuit Circuit malfunction
0150 RH bank front HO2S signal Circuit malfunction
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-35
0151 RH bank front HO2S signal Short circuit to ground
0152 RH bank front HO2S signal Short circuit to battery
0153 RH bank front HO2S signal Slow response
0154 RH bank front HO2S signal No activity
0155 RH bank front HO2S heater circuit Circuit malfunction
0156 RH bank rear HO2S signal Circuit malfunction
0157 RH bank rear HO2S signal Short circuit to ground
0158 RH bank rear HO2S signal Short circuit to battery
0159 RH bank rear HO2S signal Slow response
0160 RH bank rear HO2S signal No activity
0161 RH bank rear HO2S heater circuit Malfunction
0171 LH bank lambda control Fuelling too lean
0172 LH bank lambda control Fuelling too rich
0174 RH bank lambda control Fuelling too lean
0175 RH bank lambda control Fuelling too rich
0201 Fuel injector 1 Open circuit
0202 Fuel injector 2 Open circuit
0203 Fuel injector 3 Open circuit
0204 Fuel injector 4 Open circuit
0205 Fuel injector 5 Open circuit
0206 Fuel injector 6 Open circuit
0207 Fuel injector 7 Open circuit
0208 Fuel injector 8 Open circuit
0221 APP sensor switch B Range/ Performance problem
0222 APP sensor switch B Open circuit or short circuit to ground
0223 APP sensor switch B Short circuit to battery
0231 Fuel pump motor drive Short circuit to ground
0232 Fuel pump motor drive Short circuit to battery
0233 Fuel pump motor drive Circuit fault
0261 Fuel injector 1 Short circuit to ground
0262 Fuel injector 1 Short circuit to battery
0264 Fuel injector 2 Short circuit to ground
0265 Fuel injector 2 Short circuit to battery
0267 Fuel injector 3 Short circuit to ground
0268 Fuel injector 3 Short circuit to battery
0270 Fuel injector 4 Short circuit to ground
0271 Fuel injector 4 Short circuit to battery
0273 Fuel injector 5 Short circuit to ground
0274 Fuel injector 5 Short circuit to battery
0276 Fuel injector 6 Short circuit to ground
0277 Fuel injector 6 Short circuit to battery
0279 Fuel injector 7 Short circuit to ground
0280 Fuel injector 7 Short circuit to battery
0282 Fuel injector 8 Short circuit to ground
0283 Fuel injector 8 Short circuit to battery
0300 Misfire detection Random/Multiple cylinder misfire
0301 Misfire detection Cylinder 1 misfire
0302 Misfire detection Cylinder 2 misfire
0303 Misfire detection Cylinder 3 misfire
0304 Misfire detection Cylinder 4 misfire
0305 Misfire detection Cylinder 5 misfire
0306 Misfire detection Cylinder 6 misfire
P Code No. Component/Signal Fault Description
ENGINE MANAGEMENT SYSTEM – V8
18-2-36 DESCRIPTION AND OPERATION
0307 Misfire detection Cylinder 7 misfire
0308 Misfire detection Cylinder 8 misfire
0324 Knock sensors Control system error
0327 LH bank knock sensor 1 Short circuit to ground
0328 LH bank knock sensor 1 Short circuit to battery
0332 RH bank knock sensor 3 Short circuit to ground
0333 RH bank knock sensor 3 Short circuit to battery
0335 CKP sensor Signal implausible
0340 LH bank CMP sensor Signal implausible
0342 LH bank CMP sensor Short circuit to ground
0343 LH bank CMP sensor Short circuit to battery
0345 RH bank CMP sensor Signal implausible
0347 RH bank CMP sensor Short circuit to ground
0348 RH bank CMP sensor Short circuit to battery
0370 Reference mark detection Timing reference high resolution signal A
0411 SAI vacuum solenoid valve Incorrect flow detected
0412 SAI vacuum solenoid valve drive Circuit malfunction
0413 SAI vacuum solenoid valve drive Open circuit
0414 SAI vacuum solenoid valve drive Short circuit
0418 SAI air injection pump relay Open circuit
0420 LH bank catalytic converter Efficiency below threshold – light off too
long
0430 RH bank catalytic converter Efficiency below threshold – light off too
long
0442 EVAP system Minor leak (1.0 mm or less)
0443 Purge valve drive Circuit malfunction
0444 Purge valve drive Open circuit
0445 Purge valve drive Short circuit to battery or ground
0455 EVAP system Major leak (more than 1.0 mm)
0456 EVAP system Minor leak (0.5 mm or less)
0461 Fuel tank level signal Range/Performance problem
0462 Fuel tank level signal Short circuit to ground
0463 Fuel tank level signal Short circuit to battery
0464 Fuel tank level signal Circuit intermittent
0491 SAI system Malfunction on LH bank
0492 SAI system Malfunction on RH bank
0500 Vehicle speed signal Signal implausible
0501 Rough road detection vehicle speed
signal
Intermittent, erratic or high
0503 Rough road detection vehicle speed
signal
Range/Performance
0512 Comfort start Request circuit malfunction
0530 A/C refrigerant pressure sensor Signal fault
0532 A/C refrigerant pressure sensor Short circuit to ground
0533 A/C refrigerant pressure sensor Short circuit to battery
0561 Battery voltage monitor System voltage unstable
0562 Battery voltage monitor System voltage low
0563 Battery voltage monitor System voltage high
0571 Brake lights switch Cruise control/brake switch circuit A
0604 ECM self test RAM error
0605 ECM self test ROM error
0606 ECM self test Processor fault
0615 Comfort start relay drive Open circuit
P Code No. Component/Signal Fault Description
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-37
0616 Comfort start relay drive Short circuit to ground
0617 Comfort start relay drive Short circuit to battery
0634 ECU internal temperature ECU temperature high
0650 MIL output drive Open circuit, or short circuit to ground or
battery
0660 Manifold valve output drive Control circuit malfunction
0661 Manifold valve output drive Open circuit or short circuit to ground
0662 Manifold valve output drive Short circuit to battery
0691 Engine cooling fan control Short circuit to ground
0692 Engine cooling fan control Short circuit to battery
0693 Engine cooling fan control Circuit intermittent
0704 A/C compressor clutch switch Input circuit malfunction
1000 DMTL pump motor drive Intermittent or short circuit to ground or
battery
1102 Throttle position to mass air flow
plausibility not active
Air mass too small
1103 Throttle position to mass air flow
plausibility not active
Air mass too large
1117 Thermostat monitoring sensor Short circuit to ground
1118 Thermostat monitoring sensor Open circuit or short circuit to battery
1120 APP sensor Implausible signals
1121 APP sensor 1 Range/ Performance problem
1122 APP sensor 1 Short circuit to ground
1123 APP sensor 1 Short circuit to battery
1129 HO2S Swapped sensors (LH to RH)
1161 LH bank lambda control Adaption per ignition too small
1162 LH bank lambda control Adaption per ignition too large
1163 RH bank lambda control Adaption per ignition too small
1164 RH bank lambda control Adaption per ignition too large
1170 LH bank front HO2S signal Fuel trim malfunction
1171 LH bank lambda control Adaption over time too large
1172 LH bank lambda control Adaption over time too small
1173 RH bank front HO2S signal Fuel trim malfunction
1174 RH bank lambda control Adaption over time too large
1175 RH bank lambda control Adaption over time too small
1221 APP sensor 2 Range/ Performance problem
1222 APP sensor 2 Short circuit to ground
1223 APP sensor 2 Short circuit to battery
1300 Misfire detection Catalyst damaging misfire
1301 Misfire detection Multiple cylinder misfire
1327 LH bank knock sensor 2 Short circuit to ground
1328 LH bank knock sensor 2 Short circuit to battery
1332 RH bank knock sensor 4 Short circuit to ground
1333 RH bank knock sensor 4 Short circuit to battery
1413 SAI air injection pump relay Short circuit to ground
1414 SAI air injection pump relay Short circuit to battery
1450 DMTL pump motor Reference current above limit
1451 DMTL pump motor Reference current below limit
1452 DMTL pump motor Reference current unstable
1453 DMTL pump motor Changeover valve stuck
1454 DMTL changeover valve drive Short circuit to battery
1455 DMTL changeover valve drive Short circuit to ground
1456 DMTL changeover valve drive Open circuit
P Code No. Component/Signal Fault Description
ENGINE MANAGEMENT SYSTEM – V8
18-2-38 DESCRIPTION AND OPERATION
Several different drive cycles are defined by OBD legislation for fault diagnosis. Each drive cycle is a precise routine
which the engine or vehicle must undergo to produce the conditions that enable the ECM to perform diagnostic
routines. TestBook/T4 can be used to view the status and results of the diagnostic routines performed by the ECM.
When a fault code is stored, it will indicate, via TestBook/T4, the drive cycle required to verify a repair.
1481 DMTL heater output drive Signal intermittent
1482 DMTL heater output drive Open circuit or short circuit to ground
1483 DMTL heater output drive Short circuit to battery
1488 DMTL pump motor drive Open circuit
1489 DMTL pump motor drive Short circuit to ground
1490 DMTL pump motor drive Short circuit to battery
1522 Plausibility MSR intervention No activity
1523 LH bank VCC control solenoid valve Short circuit to ground
1524 LH bank VCC control solenoid valve Short circuit to battery
1525 LH bank VCC control solenoid valve Open circuit
1526 RH bank VCC control solenoid valve Open circuit
1527 RH bank VCC control solenoid valve Short circuit to ground
1528 RH bank VCC control solenoid valve Short circuit to battery
1614 Electric thermostat heater drive Open circuit
1615 Electric thermostat heater drive Short circuit to ground
1616 Electric thermostat heater drive Short circuit to battery
1619 5V reference voltage Internal reference voltage error
1620 Comfort start input Engine crank signal error (request while
engine running)
1621 Serial link with immobilisation ECU Timed out
1623 Serial link with immobilisation ECU Exchange code in EEPROM failure
1624 Serial link with immobilisation ECU EEPROM read/write failure
1626 ECM, throttle monitoring/ self test Engine torque monitoring problem
1630 ECM, throttle monitoring/ self test Throttle position control deviation
1631 Throttle drive Motor power stage fault
1632 ECM, throttle monitoring/ self test 'Limp home' position not adapted
1633 ECM, throttle monitoring/ self test Throttle position control band stuck short
1634 ECM, throttle monitoring/ self test Throttle position control band stuck long
1635 ECM, throttle monitoring/ self test Control gain adaption error
1638 ECM, throttle monitoring/ self test Throttle control range not learned
1639 ECM, throttle monitoring/ self test Throttle motor spring test failed
1645 CAN bus link with ABS ECU Timed out
1646 CAN bus link with EAT ECU Timed out
1647 CAN bus link with instrument pack Timed out
1651 CAN bus link with transfer box ECU Timed out
1659 ECM self test Torque monitor error
1660 ECM self test Limp home monitor error
1666 Serial link with immobilisation ECU Message parity bit fault (wrong code)
1672 Serial link with immobilisation ECU Exchange code implausible
1673 Serial link with immobilisation ECU No start code programmed
1674 Serial link with immobilisation ECU Message fault
1693 Serial link with immobilisation ECU False manipulation of start code by tester
interface
1694 Serial link with immobilisation ECU Start code corrupted
1700 Transfer box ECU Implausible signal
1709 CAN bus link with transfer box ECU Message information error
P Code No. Component/Signal Fault Description
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-39
The ECM only records a fault after it has occurred on more than one drive cycle. This fault strategy is referred to as
debouncing. When it is first detected, a fault is stored as a temporary fault. If the fault recurs within the next 40 warm-
up cycles, the fault is stored as a permanent fault and freeze frame data for the second occurrence is recorded. If the
fault does not recur within the next 40 warm-up cycles, the ECM deletes the temporary fault from memory.
The ECM illuminates the MIL when requested to do so by the EAT ECU, to perform a bulb check when the ignition is
switched on and for any emissions related fault. There is no MIL illumination for non emission related engine
management faults.
Resetting the adaptions will clear all adaptions from the ECM memory.
Drive Cycles
TestBook/T4 drive cycles are as follows:
Drive cycle A
1 Switch on the ignition for 30 seconds.
2 Ensure engine coolant temperature is less than 60 °C.
3 Start the engine and allow to idle for 2 minutes.
4 Connect TestBook/T4 and check for fault codes.
Drive cycle B
1 Switch ignition on for 30 seconds.
2 Ensure engine coolant temperature is less than 60 °C.
3 Start the engine and allow to idle for 2 minutes.
4 Perform 2 light accelerations, i.e. 0 to 35 mph with light pedal pressure.
5 Perform 2 medium accelerations, i.e. 0 to 45 mph with moderate pedal pressure.
6 Perform 2 hard accelerations, i.e. 0 to 55 mph with heavy pedal pressure.
7 Allow engine to idle for 2 minutes.
8 Connect TestBook/T4 and, with the engine still running, check for fault codes.
Drive cycle C
1 Switch ignition on for 30 seconds.
2 Ensure engine coolant temperature is less than 60 °C.
3 Start the engine and allow to idle for 2 minutes.
4 Perform 2 light accelerations, i.e. 0 to 35 mph with light pedal pressure.
5 Perform 2 medium accelerations, i.e. 0 to 45 mph with moderate pedal pressure.
6 Perform 2 hard accelerations, i.e. 0 to 55 mph with heavy pedal pressure.
7 Cruise at 60 mph for 8 minutes.
8 Cruise at 50 mph for 3 minutes.
9 Allow engine to idle for 3 minutes.
10 Connect TestBook/T4 and, with the engine still running, check for fault codes.
The following areas have an associated readiness test which must be flagged as complete, before a problem
resolution can be verified:
l Catalytic converter fault.
l Evaporative loss system fault.
l HO2S fault.
l HO2S heater fault.
When carrying out drive cycle C to determine a fault in any of the above areas, select the readiness test icon to verify
that the test has been flagged as complete.
ENGINE MANAGEMENT SYSTEM – V8
18-2-40 DESCRIPTION AND OPERATION
Drive cycle D
1 Switch ignition on for 30 seconds.
2 Ensure engine coolant temperature is less than 35 °C.
3 Start the engine and allow to idle for 2 minutes.
4 Perform 2 light accelerations, i.e. 0 to 35 mph with light pedal pressure.
5 Perform 2 medium accelerations, i.e. 0 to 45 mph with moderate pedal pressure.
6 Perform 2 hard accelerations, i.e. 0 to 55 mph with heavy pedal pressure.
7 Cruise at 60 mph for 5 minutes.
8 Cruise at 50 mph for 5 minutes.
9 Cruise at 35 mph for 5 minutes.
10 Allow engine to idle for 2 minutes.
11 Connect TestBook/T4 and check for fault codes.
Drive cycle E
1 Ensure fuel tank is at least a quarter full.
2 Carry out drive cycle A.
3 Switch off ignition.
4 Leave vehicle undisturbed for 20 minutes.
5 Switch on ignition.
6 Connect TestBook/T4 and check for fault codes.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-41
DESCRIPTION AND OPERATION
Variable Camshaft Control Components
1 Locking nut
2 Impulse wheel
3 Camshaft to sprocket retaining screw
4 VCC transmission unit
5 Bolt
6 Oil distribution flange
7 Oil distribution flange gasket
8 Inlet camshaft
9 Exhaust camshaft
10 Drive train gear retaining bolt
11 Check valve
12 VCC solenoid valve
ENGINE MANAGEMENT SYSTEM – V8
18-2-42 DESCRIPTION AND OPERATION
VCC System
Introduction
The variable intake valve timing system on the V8 is known as Variable Camshaft Control (VCC).
The V8 VCC system is a new system providing stepless VCC functionality on each intake camshaft. The system is
continuously variable within its range of adjustment providing optimised camshaft positioning for all engine operating
conditions.
While the engine is running, both intake camshafts are continuously adjusted to their optimum positions. This
enhances engine performance and reduces exhaust emissions.
Both camshafts are adjusted simultaneously within 20° (maximum) of the camshafts rotational axis.
1 VCC transmission unit 2 VCC control solenoid valve
This equates to a maximum span of 40° crankshaft rotation. The camshaft spread angles for both banks are as
follows.
M18 0818
20 20
1
2
1
2
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-43
A = Valve lift
B = Crankshaft rotation
C = Open duration 228
°
D = Open duration 236
°
E = Default retard
F = Maximum retard
G = Exhaust valve
H = Intake valve
The design of a camshaft for a non adjustable valve timing system is limited to the required overall performance of
the engine.
An intake camshaft with an advanced (early) profile will provide a higher performing power curve at a lower engine
speed. But at idle speed the advanced position will create a large area of intake/exhaust overlap that causes a rough,
unstable idle.
An intake camshaft with a retarded (late) profile will provide a very smooth, stable idle but will lack the cylinder filling
dynamics needed for performance characteristics at mid range engine speeds.
The ability to adjust the valve timing improves the engines power dynamics and reduces exhaust emissions by
optimising the camshaft angle for all ranges of engine operation. VCC provides the following benefits:
l Increased torque at lower to mid range engine speeds without a loss of power in the upper range engine speeds
l Increased fuel economy due to optimised valve timing angles
l Reduction of exhaust emissions due to optimised valve overlap
l Smoother idle quality due to optimised valve overlap.
M18 0826
B
H
E
F
A
G
C
D
ENGINE MANAGEMENT SYSTEM – V8
18-2-44 DESCRIPTION AND OPERATION
Variable Camshaft Control Electronic Control
The following describes the electronic control of the VCC system.
Electronic Control
The engine control module is responsible for activating a VCC variable position solenoid valve based on EMS
program mapping. The activation parameters are influenced by the following input signals:
l Engine speed
l Load (intake air mass)
l Engine temperature
l Camshaft position.
Mechanical Control
The position of the solenoid valve directs the hydraulic flow of engine oil. The controlled oil flow acts on the mechanical
components of VCC system to position the camshaft.
The hydraulic engine oil flow is directed through advance or retard activation oil ports by the VCC solenoid. Each port
exits into a sealed chamber on the opposite sides of a control piston.
In its default position the oil flow is directed to the rear surface of the piston. This pulls the helical gear forward and
maintains the retarded valve timing position.
When the oil flow is directed to the front surface of the piston, the oil pushes the helical gear in the opposite direction
which rotates the matched helical gearing connected to the camshaft.
The angled teeth of the helical gears cause the pushing movement to be converted into a rotational movement. The
rotational movement is added to the turning of the camshaft providing the variable camshaft positioning.
System Components
The V8 VCC components include the following for each cylinder bank:
l Cylinder heads with oil ports for VCC
l VCC transmission with sprockets
l Oil distribution flange
l Oil check valve
l PWM controlled solenoid valve
l Camshaft position impulse wheel.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-45
Control Solenoid and Check Valve
A = Advance
B = Retard
C = Vent
The VCC solenoid is a two wire, pulse width modulated, oil pressure control valve. The valve has four ports;
1 Input Supply Port, Engine Oil Pressure
2 Output Retard Port, to rear of piston/helical gear (retarded camshaft position)
3 Output Advance Port , to front of piston/helical gear (advanced camshaft position)
4 Vent released oil pressure.
A check valve is positioned forward of the solenoid in the cylinder head oil gallery. The check valve maintains an oil
supply in the VCC transmission and oil circuits after the engine is turned off. This prevents the possibility of piston
movement (noise) within the VCC transmission system on the next engine start.
VCC Transmission
The primary and secondary timing chain sprockets are integrated with the VCC transmission. The transmission is a
self contained unit.
The adjustment of the camshaft occurs inside the transmission, controlled oil pressure then moves the piston axially.
The helical gear cut of the piston acts on the helical gears on the inside surface of the transmission and rotates the
camshaft to the specific advanced or retarded angle position.
Three electrical pin contacts are located on the front surface to verify the default maximum retard position using an
ohmmeter. This is required during assembly and adjustment. (see service notes further on).
Oil Distribution Flanges:
The oil distribution flanges are bolted to the front surface of each cylinder head. They provide a mounting location for
the VCC solenoids as well as the advance-retard oil ports from the solenoids to the intake camshafts.
M18 0812A
A
B
C
ENGINE MANAGEMENT SYSTEM – V8
18-2-46 DESCRIPTION AND OPERATION
Camshafts
Each intake camshaft has two oil ports separated by three sealing rings on their forward ends.
The ports direct pressurized oil from the oil distribution flange to the inner workings of the VCC transmission.
Each camshaft has REVERSE threaded bores in their centres for the attachment of the timing chain sprockets on the
exhaust cams and the VCC transmissions for each intake camshaft as shown.
Camshaft Position Impulse Wheels:
The camshaft position impulse wheels provide camshaft position status to the engine control module via the camshaft
position sensors. The asymmetrical placement of the sensor wheel pulse plates provides the engine control module
with cylinder specific position ID in conjunction with crankshaft position.
V8 VCC Control
As the engine camshafts are rotated by the primary and secondary timing chains, the ECM activates the VCC
solenoids via a PWM (pulse width modulated) ground signal based on a program map. The program is influenced by
engine speed, load, and engine temperature.
In its inactive or default position, the valves direct 100% engine oil pressure flow to achieve maximum “retard ”VCC
positioning
Maximum Retard Position
M18 0811
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-47
As the Pulse Width Modulation (PWM) increases on the control signal, the valve progressively opens the advance oil
port and proportionately closes the retarded oil port.
Mid Position
Oil pressure pushes the piston toward the advance position. Simultaneously the oil pressure on the retarded side
(rear) of the piston is decreased and directed to the vent port in the solenoid valve and drains into the cylinder head.
M18 0832
ENGINE MANAGEMENT SYSTEM – V8
18-2-48 DESCRIPTION AND OPERATION
At maximum PWM control, 100% oil flow is directed to the front surface of the piston pushing it rearward to maximum
advance.
Maximum Advance Position
Varying the pulse width (on time) of the solenoids control signals proportionately regulates the oil pressures on each
side of the pistons to achieve the desired VCC advance angle.
M18 0833
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-49
VCC Timing Procedures
Always refer to the Service Procedures Workshop Manual for valve timing procedures. The V8 valve timing
adjustment requires the setting of the VCC transmissions to their maximum retard positions with an ohmmeter and
attaching the camshaft gears to each camshaft with single reverse threaded bolts.
The process is as follows:
l After locking the crankshaft at TDC, the camshaft alignment tools are placed on the square blocks on the rear of
the camshafts locking them in place
l The exhaust camshaft sprockets and VCC transmission units with timing chains are placed onto their respective
camshafts
l The exhaust camshaft sprockets and VCC transmissions are secured to the camshafts with their respective
single, reverse threaded bolt. Finger tighten only at this point. Install the chain tensioner into the timing chain case
and tension the chain
l Connect an ohmmeter across two of the three pin contacts on the front edge of one of the VCC transmissions.
Twist the inner hub of transmission to the left (counter clock- wise). Make sure the ohmmeter indicates closed
circuit. This verifies that the trans- mission in the default maximum retard position
l Using an open end wrench on the camshaft to hold it in place, torque the VCC trans- mission centre bolt to
specification.
Camshaft Impulse Wheel Position Tools
The camshaft impulse wheels require a special tool set to position them correctly prior to torquing the retaining nuts.
The impulse wheels are identical for each cylinder bank. The alignment hole in each wheel must align with the tools
alignment pin. Therefore the tools are different and must be used specifically for their bank.
The tool rests on the upper edge of the cylinder head and is held in place by the timing case bolts.
VCC Solenoid Replacement
Refer to the Service Procedures Workshop Manual for complete solenoid replacement procedure.
The solenoids are threaded into the oil distribution flanges through a small opening in the upper timing case covers.
VCC Transmission Retard Position Set Up Tools
A special tool (see Service Procedures Workshop Manual for correct tool number) is used to rotate the transmission
to the full retard position when checking the piston position with an ohmmeter.
This tool engages the inner hub of the transmission to provide an easy method of twisting it to the left for the ohmmeter
test.
Diagnostics
The VCC is fully compatible with the diagnostic software providing specific fault codes and test modules. Additionally,
diagnostic requests section provides status of the PWM of the VCC solenoids and camshaft position feedback via the
camshaft position sensors. The Service Functions section of the TestBook/T4 also provides a VCC system test.
ENGINE MANAGEMENT SYSTEM – V8
18-2-50 DESCRIPTION AND OPERATION
DESCRIPTION AND OPERATION
Cruise Control Component Location
1 Diagnostic socket
2 Instrument pack
3 Cruise control switch pack
4 Main fuse
5 ABS/DSC ECU
6 Brake light switch
7 Accelerator pedal position sensor (APP)
8 Electric throttle.
9 EMS ECU
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-51
Cruise Control System Control Diagram
A = Hardwired connections; D = CAN bus; J = ISO 9141 K line bus; K = I bus
M18 0817A
K
A
12
3
4
6
7
9
8
10
12
13
11
JJ
D
5
ENGINE MANAGEMENT SYSTEM – V8
18-2-52 DESCRIPTION AND OPERATION
1 Main fuse
2 Cruise control switch pack
3 Rotary coupler
4 Instrument pack
5 EAT ECU
6 ABS/DSC ECU
7 Brake light switch
8 Diagnostic socket
9 Electric throttle
10 Accelerator pedal position sensor (APP)
11 ECM
12 Fuse 9, switch supply (5 amp)
13 Ignition switch
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-53
Cruise Control
General
Cruise control functionality is fully integrated into the ECM and uses electric throttle intervention to automatically
maintain a set vehicle speed. Once engaged, the system can also be used to accelerate the vehicle without using the
accelerator pedal. The cruise control system consists of:
l Cruise control master switch
l +/- Speed switch
l Resume switch
l EMS ECU
l Electric throttle.
The Controller Area Network (CAN) bus is used by the cruise control system for the exchange of data between the
ECM, EAT ECU, DSC ECU and instrument pack.
Cruise control is enabled when the master switch is pressed. Once enabled, the cruise control system is operated
using the steering wheel switches. The steering wheel switches output a serial data stream to the ECM, the ECM then
adjusts the electric throttle to maintain the vehicle at the set speed.
The cruise control warning lamp provides a visual indication of when the system is engaged.
Master Switch
The master switch controls a feed to the ECM to enable the system. The switch is a momentary contact push switch
on the left hand steering wheel switch pack.
Steering Wheel Switches
The steering wheel switches, SET+ and RES, are non latching push switches that engage and disengage cruise
control and adjust the set speed. While pressed, the switches supply a serial data stream to the ECM to adjust the
set speed.
ECM
The ECM receives serial data from the steering wheel switches, which are interpreted by the ECM to operate cruise
control. The ECM also controls the output of a cruise engaged signal to the EAT ECU.
The ECM incorporates a software module and associated components to enable cruise control operation by direct
control of the electric throttle. In addition to controlling the throttle, the software module monitors hardwired and CAN
bus inputs to the ECM and prevents or suspends cruise control operation when the vehicle is not in the correct driving
configuration.
While the master switch is selected off, only the OFF message can be transmitted. When the master switch is
selected on, the power feed from the switch enables the interface switches to send either the SET or RESUME
messages, depending on the inputs from the steering wheel switches and the cruise control status message from the
CAN bus. When the master switch is first switched on, the output of the RESUME message is automatically inhibited
until after the first engagement of cruise control.
When cruise control is engaged, the ECM outputs a signal on CAN to the EAT ECU to provide a cruise control
engaged signal. The EAT ECU uses the signal to switch between normal and cruise control modes of operation.
Brake Pedal Sensor
Outputs from the brake pedal sensor are supplied to the ECM to enable the system to detect when the brakes are
applied. The brake pedal sensor is a Hall effect sensor that produces two outputs. Both outputs should be 0 to 2 volts
while the brake pedal is released. When the brake pedal is pressed, the Brake Lamp Switch (BLS) output increases
to between 6 and battery volts, the Brake Lamp Test Switch (BLTS) output increases to between 10 and battery volts.
ENGINE MANAGEMENT SYSTEM – V8
18-2-54 DESCRIPTION AND OPERATION
Cruise Control Operation
Cruise control is operated from the steering wheel mounted switches. Switch symbols are market dependent! There
are 4 switches for cruise control.
1 Cruise control ON/OFF switch (O/I)
2 Cruise control accelerate/tip-up switch (+)
3 Cruise control decelerate/tip-down switch (-)
4 Cruise control resume switch.
The driver can enable cruise control at any time by pressing the ON/OFF (O/I) switch. Pressing this switch places the
cruise control function into "stand by mode" and illuminates the instrument pack mounted cruise control lamp.
When in "stand-by" mode, pressing the "+", "-" or "RESUME " cruise switch once will activate the cruise control
function and set the "set speed" equal to the current vehicle speed.
Note that the vehicle speed has to be greater than the minimum cruise control speed value of 26 km/h (16 mph) for
the cruise control function to operate. There is no maximum speed limit.
Once the cruise control function is active, switch presses will have the following actions:
l Each "short" press on the "+" switch will cause the "set speed" to be increased by 1 km/h (tip-up function
l Each "short" press on the "-" switch will cause the "set speed" to be decreased by 1 km/h (tip-down function).
Note that the "set speed" cannot be adjusted to lower than the minimum cruise control speed value
l A "continuous" press on the "+" switch will cause the vehicle to accelerate until the switch is released. The vehicle
speed at the point the switch is released becomes the new "set speed"
l A "continuous" press on the "-" switch will cause the vehicle to decelerate until the switch is released. The vehicle
speed at the point the switch is released becomes the new "set speed". Note that the "set speed" cannot be
adjusted to lower than the minimum cruise control speed value
l A press on the "RESUME" switch when returned to "stand-by" mode will re-activate the cruise control function
using the remembered "set speed".
Other aspects of the cruise control function are:
l Pedal over-ride function
l If the driver uses the accelerator pedal while cruise control is active, the "set speed" remains unchanged.
Hence when the driver releases the accelerator pedal, the cruise control function will remain active and return
the vehicle to the current "set speed"
l If the driver presses the "+" or "-" switches during pedal over-ride, the "set speed" will change to the actual
vehicle speed when the switch is pressed.
l The cruise control function is not available in "low range". Note however, that if cruise control was active or in
stand-by mode when low range was selected, the cruise function will automatically return to stand-by mode when
high range is re-engaged, and the previous set speed is remembered.
l When in stand-by mode, pressing the "I/O" switch will disable the cruise control function, switch OFF the
instrument pack mounted cruise control lamp, and the "set speed" will be lost
l The cruise control function will change from "active" to "stand-by" modes if:
l The driver brakes
l The driver presses the "O/I" switch
l The driver moves from "D" to "N"
l The driver selects "low range"
l The DSC system activates above a defined level. This should be indicated to the driver by the instrument pack
"DSC active" warning lamp.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-55
DESCRIPTION AND OPERATION
EVAP System
1 Charcoal canister vent hose
2 Atmospheric vent pipe
3 Vapour separator
4 Charcoal canister
ENGINE MANAGEMENT SYSTEM – V8
18-2-56 DESCRIPTION AND OPERATION
Emissions
Evaporative Emissions (EVAP) Purge Valve
The EVAP purge valve is located on the LH side of the engine in the line between the charcoal canister and the inlet
manifold. The EVAP purge valve is part of the EVAP control system and is used to control the extraction of fuel vapour
stored in the EVAP canister.
The EVAP control system reduces the level of hydrocarbons released into the atmosphere by fuel vapour venting from
the fuel tank. The system comprises fuel cut off valves, a vapour separator, a two way valve, vent lines, the canister
and the purge valve.
Purge Valve
The ECM controls the amount of vapour drawn from the charcoal canister by controlling the length of time the purge
valve is open. It controls the length of time it is open by supplying the purge valve with a PWM voltage. Control is used
to maintain the required level of emissions, as a hydrocarbon vapour level of 1% can affect the air/fuel ratio by as
much as 20%.
The ECM can diagnose faults with the purge valve and will store the related fault codes, along with details of the
engine speed, battery voltage and intake air temperature. The driver may notice the following effects if the purge valve
fails in the open position:
l The engine may stall periodically when returning to idle
l The engine may suffer from poor idle quality
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-57
Secondary Air Injection
The ECM controls the secondary air injection which is used to quickly heat the catalytic converters for emission
legislation compliance.
1 Non return valve
2 Vacuum vent valve
3 Vacuum reservoir
4 SAI pump
The ECM controls the vacuum vent valve and the air injection pump relay. The air pump operates at a start
temperature of between –9°C and 50°C. The pump continues to operate for a maximum of 2 minutes, when the engine
speed drops to idle.
Note that the secondary air valve is always open when the air pump is operating.
The secondary air injection system is used to limit the emission of carbon monoxide (CO) and hydrocarbons (HC) that
are prevalent in the exhaust during cold starting of a spark ignition engine. The concentration of hydrocarbons
experienced during cold starting at low temperatures are particularly high until the engine and catalytic converter
reach normal operating temperature. The lower the cold start temperature, the greater the prevalence of
hydrocarbons emitted from the engine.
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M19 3550
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ENGINE MANAGEMENT SYSTEM – V8
18-2-58 DESCRIPTION AND OPERATION
There are several reasons for the increase of HC emissions at low cold start temperatures, including the tendency for
fuel to be deposited on the cylinder walls, which is then displaced during the piston cycle and expunged during the
exhaust stroke. As the engine warms up through operation, the cylinder walls no longer retain a film of fuel and most
of the hydrocarbons will be burnt off during the combustion process.
The SAI pump is used to provide a supply of air into the exhaust ports in the cylinder head, onto the back of the
exhaust valves, during the cold start period. The hot unburnt fuel particles leaving the combustion chamber mix with
the air injected into the exhaust ports and immediately combust. This subsequent combustion of the unburnt and
partially burnt CO and HC particles help to reduce the emission of these pollutants from the exhaust system. The
additional heat generated in the exhaust manifold also provides rapid heating of the exhaust system catalytic
converters. The additional oxygen which is delivered to the catalytic converters also generate an exothermic reaction
which causes the catalytic converters to 'light off' quickly.
The catalytic converters only start to provide effective treatment of emission pollutants when they reach an operating
temperature of approximately 250°C (482°F) and need to be between temperatures of 400°C (752°F) and 800°C
(1472°F) for optimum efficiency. Consequently, the heat produced by the secondary air injection “after burning”,
reduces the time delay before the catalysts reach an efficient operating temperature.
The engine control module (ECM) checks the engine coolant temperature when the engine is started, and if it is above
-9º C but below 75°C, the SAI pump is started. Secondary air injection will remain operational for a period controlled
by the ECM. The SAI pump operation can be cut short due to excessive engine speed or load.
Air from the SAI pump is supplied to the cylinder head, via a metal pipe which splits the air flow evenly to each bank.
At the same time the secondary air pump is started, the ECM operates a SAI vacuum solenoid valve, which opens to
allow vacuum from the reservoir to be applied to the non return valve on the metal delivery tube on the engine.
Secondary air is injected into the inner most exhaust ports on each bank.
When the ECM breaks the ground circuit to de-energise the SAI vacuum solenoid valve, the vacuum supply to the
SAI non return valve is cut off and the valve is closed to prevent further air being injected into the exhaust manifold.
At the same time as the SAI vacuum solenoid valve is closed, the ECM opens the ground circuit to the SAI pump
relay, to stop the SAI pump.
A vacuum reservoir is included in the vacuum line between the intake manifold and the SAI vacuum solenoid valve.
This prevents changes in vacuum pressure from the intake manifold being passed on to cause fluctuations of the
secondary air injection solenoid valve. The vacuum reservoir contains a one way valve and ensures a constant
vacuum is available for the SAI vacuum solenoid valve operation. This is particularly important when the vehicle is at
high altitude.
ENGINE MANAGEMENT SYSTEM – V8
DESCRIPTION AND OPERATION 18-2-59
Secondary Air Injection System Components
The secondary air injection (SAI) system components are described below:
Secondary Air Injection (SAI) Pump
The SAI pump is attached to a bracket at the front LH side of the engine compartment and is fixed to the bracket by
three studs and nuts. The pump is electrically powered from a 12V battery supply via a dedicated relay and supplies
approximately 35kg/hr of air when the vehicle is at idle in Neutral/Park on a start from 20°C (68°F).
Air is drawn into the pump from the "clean" side of the air cleaner. The air is delivered to the cylinder head on each
side of the engine through a metal pipe.
The foam filter in the air intake of the SAI pump provides noise reduction and protects the pump from damage due to
particulate contamination.
If the secondary air injection pump malfunctions, fault codes may be stored in the ECM diagnostic memory, which can
be retrieved using Testbook/T4.
Secondary Air Injection (SAI) Pump Relay
The secondary air injection pump relay, coloured pink for identification, is located in the E-Box. The engine control
module (ECM) is used to control the operation of the SAI pump via the SAI pump relay. Power to the coil of the relay
is supplied from the vehicle battery via the main relay and the ground connection to the coil is via the ECM.
Secondary Air Injection Non Return Valve
The secondary air injection non return valve is located on the steel air delivery tube at the front of the engine. The
valve is controlled by the ECM via the vacuum vent solenoid.
Vacuum Vent Valve
ENGINE MANAGEMENT SYSTEM – V8
18-2-60 DESCRIPTION AND OPERATION
FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-1
FUEL DELIVERY SYSTEM – Td6DESCRIPTION AND OPERATION
Td6 Fuel Delivery Component Location –
Sheet 1 of 2
1 Cooling fan (hot climate markets only)
2 Fuel cooler
3 Fuel temperature sensor housing
4 Fuel temperature sensor
5 Fuel filter
6 Bimetallic valve
7 High pressure fuel pump
8 Fuel rail
9 Spill return pipe.
10 Fuel rail pressure sensor
M19 3541
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FUEL DELIVERY SYSTEM – TD6
19-1-2 DESCRIPTION AND OPERATION
Td6 Fuel Delivery Component Location –
Sheet 2 of 2
FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-3
1 Fuel filler cap
2 Fuel pump
3 Fuel tank
4 Secondary fuel pump
5 Fuel return pipe
6 Fuel delivery pipe
7 Fuel filler tube
FUEL DELIVERY SYSTEM – TD6
19-1-4 DESCRIPTION AND OPERATION
Td6 Fuel System Schematic
M19 3585
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FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-5
1 Common rail
2 Fuel rail pressure sensor
3 Injector
4 Bi-metal valve
5 Fuel cooler
6 Fan temperature switch
7 Fuel temperature sensor
8 Electric fan
9 Restrictor
10 Fuel pump
11 Secondary fuel pump
12 Fuel filter
13 LP Pressure sensor
14 Differential pressure valve
15 High pressure fuel pump
16 Pressure control valve
FUEL DELIVERY SYSTEM – TD6
19-1-6 DESCRIPTION AND OPERATION
Description
General
The Td6 is equipped with a high pressure common rail fuel injection system. With this fuel injection process, a high
pressure pump delivers a uniform level of pressure to the shared fuel line (the common rail) which serves all the fuel
injection valves. Pressure develops to the optimum level for smooth operation. This means that each injector nozzle
is capable of delivering fuel at spray pressures of up to 1350 bar.
The common rail system disconnects fuel injection and pressure generation functions. Fuel injection pressure is
generated independently of engine speed and fuel injection volume and is available in the "Rail" for injection to the
cylinders.
The fuel injection timing and volume are calculated in the DDE and delivered to each engine cylinder by the injectors,
each of which is actuated by energizing the appropriate solenoid valve.
The fuel system is divided into 2 sub systems:
l Low pressure system
l High pressure system.
The low pressure system features the following components:
l Fuel tank
l Advance delivery pump
l Outlet protection valves
l Auxiliary delivery pump
l Fuel filter with inlet pressure sensor
l Pressure relief valve (LP system)
l Fuel cooler.
The high pressure system features the following components:
l High pressure pump
l High pressure common rail
l Pressure control valve
l Rail pressure sensor
l Injectors.
The low pressure system pressure is approx. 1.5 bar to 5 bar and return end < 0.6 bar. The pressure in the high
pressure end is 200 bar to 1350 bar.
Fuel Tank
The fuel tank is a saddle type tank and is constructed from moulded plastic. It is located towards the rear of the vehicle
just in front of the rear axle. The fuel tank has a 100 litre capacity with a fuel warning lamp in the instrument pack
which is activated when the fuel level reaches 10 litres. The tank incorporates one roll over valve to prevent fuel
leakage through the vent in the event of an accident.
FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-7
Advance Delivery Pump
The electrical fuel pump is located inside the fuel tank in the left hand side of the tank.
The pump transports fuel from the fuel swirl pot towards the "engine" and operates the syphon jet pumps in the left
and right sides of the tank. Both syphon jet pumps deliver fuel to the fuel swirl pot in the right side of the tank.
The pump is controlled by the ECM via the fuel pump relay.
Should the fuel pump electrical connection need to be disconnected, it is imperative that the ignition should be
switched off. If the ignition is on in any position the fuel gauge will memorise its last needle position prior to power
down. Once power is restored the gauge will display the last remembered position regardless of the actual level of
fuel in the tank. This could result in incorrect fuel gauge readings if the fuel tank has been drained and not filled worth
exactly the same quantity of fuel that was removed.
FUEL DELIVERY SYSTEM – TD6
19-1-8 DESCRIPTION AND OPERATION
Secondary Pump
Secondary Pump
The secondary fuel pump is located on the side of the fuel tank. The pump is an in line electric pump and boosts the
fuel pressure for delivery to the High pressure pump. The pump is activated at the same time as the electric fuel pump
by the ECM controlling the fuel pump relay.
High Pressure Fuel Injection Pump
The high pressure fuel injection pump is located at the front of the engine and is driven by a chain from the crankshaft.
The pump has maximum delivery pressure of 1350 bar.
The high pressure pump is the interface between the low pressure and the high pressure fuel systems. The pump has
the task of ensuring that there is always enough fuel delivered at a sufficient pressure in operating conditions over the
entire service life of the vehicle. This includes the delivery of spare fuel, required for a rapid start and pressure
increase in the fuel rail.
FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-9
High Pressure Fuel Pump Cross Section
1 Drive shaft
2 Cam
3 Piston
4 Chamber
5 Inlet valve
6 Pressure valve
7 HP supply to fuel rail
8 Pressure control valve
9 Ball valve
10 HP return
11 LP fuel supply
12 Safety valve with throttle bore
13 LP fuel gallery
Fuel is delivered via the filter to the high pressure fuel pump intake and the safety valve situated behind it. It is forced
through the throttle bore into the low pressure duct. This duct is connected to the lubrication and coolant circuit of the
high pressure pump. It is therefore not connected to an oil circuit.
The drive shaft is driven via the chain drive at more than half of the engine speed (max. 3300 rpm). It moves the three
pump pistons up and down with its eccentric cam, depending on the cam shape.
If the pressure in the low-pressure duct exceeds the opening pressure of the suction valve (0.5 -1.5 bar), the advance
delivery pump can force fuel into the element chamber where the pump piston moves downwards (suction stroke). If
the dead centre point of the pump piston is exceeded, then the intake valve closes. The fuel in the element chamber
can no longer escape. It is then compressed in the intake line by the delivery pressure. The accumulating pressure
opens the exhaust valve as soon as the pressure in the rail is achieved. The compressed fuel enters the high pressure
system.
The pump piston delivers fuel until the upper dead centre point is reached (delivery stroke). The pressure then falls
again, which closes the outlet valve. The remaining fuel is no longer subject to pressure. The pump piston moves
downwards.
If the pressure in the element chamber falls below the pressure in the low pressure duct, then the intake valve opens
again. The whole process is repeated from the beginning.
The high pressure pump constantly generates the system pressure for the high pressure accumulator (rail). The
pressure in the rail is determined by the pressure control valve.
The high pressure is generated by means of three pump pistons arranged radially within the high pressure pump.
Three delivery strokes per revolution ensure low injection torque and uniform load over the pump drive. At 16 Nm, the
average torque is only approx. 1/9 of the drive torque required for a comparable distributor pump.
M19 3609
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FUEL DELIVERY SYSTEM – TD6
19-1-10 DESCRIPTION AND OPERATION
The power required for the pump drive increases proportionally to the set pressure in the rail and to the pump speed
(delivery volume).
Since the high pressure pump is designed for large delivery quantities, there is an excess of compressed fuel when
the vehicle is idling or only subject to partial load. Since the compressed fuel is no longer subject to pressure once
the excess fuel flows away, the energy generated by compression is lost and/or heats the fuel.
This excess delivered fuel is returned to the fuel tank via the pressure control valve and the fuel cooler.
Pressure Control Valve
On the Td6 engine, the pressure control valve is located at the high pressure pump.
The pressure control valve regulates the fuel rail pressure according to the load status of the engine. If the rail
pressure is too high, the pressure control valve opens, which enables some of the fuel to pass from the fuel rail to the
fuel tank via a collector line. If the rail pressure is too low, the pressure control valve closes and seals the high
pressure side from the low pressure side.
The EDC controls an armature via a coil. The armature presses a ball into a seal, which seals the high pressure side
from the low pressure side. When the system is not activated, the ball is returned by a spring. The entire armature is
coated with fuel for lubrication and cooling.
The pressure control valve has two control circuits:
l One electrical control circuit for setting a variable pressure value in the rail
l One mechanical control circuit for equalising high frequency pressure fluctuations.
The electric control circuit compensates for slow pressure fluctuations and changes and the mechanical control circuit
compensates for faster pressure fluctuations.
With the pressure control valve not active, the high pressure present in the rail or in the high pressure pump output is
exerted on the high pressure intake of the pressure control valve. Since the de-energized electro magnet is not
present, the force of the high pressure is greater than the force of the spring, which opens the pressure control valve.
The spring's design creates a pressure of max. 100 bar.
When the pressure control valve is active (to raise the fuel pressure) the magnetic force and spring force must be
increased. The pressure control valve is activated and closed until there is a balance between the high pressure force
on the one side and the magnetic and spring forces on the other. The magnetic force exerted by the electromagnet
is in direct proportion to the activation current (controlled by the EMS). Variation in the activation current is achieved
by PWM. The PWM frequency is 1 kHz i.e. high enough to prevent disturbance from armature movements and/or
fluctuation in pressure.
Fuel Rail
The Td6 engine is equipped with a common rail fuel rail. The common rail is located beside the cylinder head cover
underneath the air inlet manifold.
In the fuel rail, the fuel is subjected to high pressure and delivered to the injectors. The fuel rail feeds all cylinders and
maintains its internal pressure at a constant value, even when handling larger quantities of fuel. This ensures that the
injection pressure remains at a constant pressure when the injector is opened. Fluctuations in pressure resulting from
the pump delivery and injection are dampened by the volume of fuel in the rail.
In the Td6, the fuel rail pressure sensor is located at one end of the rail.
The fuel rail is continuously supplied with fuel from the high pressure pump. The fuel is delivered from the fuel rail to
the injectors via the injector connection lines.
Fuel Rail Pressure Sensor
On the Td6 engine, the fuel rail pressure sensor is screwed onto the end of the fuel rail.
The fuel rail pressure sensor measures the current pressure in the rail and supplies a voltage signal corresponding
to the pressure applied to the ECM.
FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-11
Fuel Rail Pressure Sensor Cross Section
1 Electrical connections
2 Evaluation switch
3 Diaphragm with sensor elements
4 High pressure connection
5 Retaining thread
The fuel reaches a sensor diaphragm through the high pressure connection. There is a sensor element located on
this diaphragm (semiconductor component) to convert the changes in shape caused by pressure into an electrical
signal. The signal generated is sent to an evaluation switch via connecting lines, which relays the prepared measuring
signal to the control unit via the connections. The diaphragm's electrical resistance varies when its shape changes.
This change in shape (approx. 1 mm per 500 bar) created by the accumulation of system pressure alters the electrical
resistance and changes the voltage of the resistance bridge which has a supply of 5 volts. This voltage is in the 0 -
70 mV range (depending on the pressure) and is increased by the evaluation switch to a range of 0.5 - 4.5 volts. The
exact measurement of the rail pressure is essential if the system is to function correctly. For this reason, the
permissible tolerance ranges for the pressure sensor are also kept to a minimum when the pressure is measured. In
the main operating range, the measuring precision is at 30 bar, i.e. at approx. ± 2 from the final value. If the rail
pressure sensor malfunctions, the pressure control valve is activated by the control unit's emergency function.
M19 3569
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FUEL DELIVERY SYSTEM – TD6
19-1-12 DESCRIPTION AND OPERATION
Injectors
The injectors are arranged in the central area above the combustion chambers in the cylinder head.
Injector Cross Section
1 Fuel return (outlet)
2 Electrical connection
3 Activation unit (2/2 solenoid valve)
4 Fuel supply (inlet), high pressure from rail
5 Valve control chamber
6 Ball valve
7 Inlet throttle
8 Outlet throttle
9 Valve control piston
10 Supply channel to nozzle
11 Nozzle needle
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FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-13
The injector can be divided into four main sections:
l Hole nozzle with injector needle
l Hydraulic servo system
l Solenoid valve
l Connections and fuel channels.
The high pressure connection (4) guides the fuel through channel (10) to the nozzle and also through the supply
throttle (7) in the control chamber (5).
The control chamber is connected to the fuel return line (1) by the outlet throttle (8), which is opened by a solenoid
valve. When the outlet throttle is closed, hydraulic force on the valve piston (9) exceeds that on the pressure stage of
the injector needle (11). Consequently, the injector needle is pressed into seat and seals the high pressure channel
off from the engine compartment. Fuel cannot enter the combustion chamber, although it is constantly pressurized at
the high pressure connection.
When the injector activation unit is actuated (2/2 solenoid valve), the outlet throttle is opened. This reduces the
pressure in the control chamber, and therefore the hydraulic force on the valve piston.
As soon as the hydraulic force drops below that on the pressure stage of the injector needle, the injector needle opens,
which allows the fuel to enter the combustion chamber through the spray apertures.
This indirect activation of the injector needle via a hydraulic force increasing system is used because the force
required to open the injector needle using the solenoid valve cannot be produced directly. The control quantity
required in addition to the fuel quantity injected enters the fuel return line via the control chamber throttle.
In addition to the pilot control volume, fuel is also lost (leakage quantity) at the nozzle needle and valve piston guides.
The control and leakage quantities can be up to 50 mm
3
per stroke. They are guided back to the fuel tank via the fuel
return line with a manifold, to which the overflow valve, high pressure pump and pressure control valve are connected.
The function of the injector can be subdivided into four operating statuses when the engine is running and the high
pressure pump is delivering fuel:
l Injector closed (under high pressure)
l Injector opens (start of injection)
l Injector fully open
l Injector closes (end of injection).
These operating statuses are applied according to the distribution of force amongst the components of the injectors.
If the engine is not running and there is an absence of pressure in the rail, the nozzle spring closes the injector.
When at rest, the 2/2-solenoid valve is not activated and is therefore closed. Because the outlet throttle is closed, the
armature ball is pressed into the lodgment at the drain throttle by the valve spring. The rail high pressure accumulates
in the valve control chamber. The same pressure is also exerted in the chamber volume of the nozzle. The forces
applied by the pressure to the surfaces of the control piston and the force of the nozzle spring keeps the injector
needle closed against the opening force attacking its pressure stage.
Wen the injector starts to open the 2/2-solenoid valve is activated by the starting current (I = 20 amps), which enables
the 2/2 solenoid valve to be opened quickly. The force of the activated electromagnet exceeds that of the valve spring
and the armature opens the final throttle. After a maximum of 450 ms, the increased starting current (I = 20 amps) is
reduced to a lower retaining current of the electromagnet (I= 12 amps). This is possible because the air gap of the
magnetic circuit is now smaller.
Opening the drain throttle allows fuel to flow out of the valve control chamber into the cavity above, and then to the
fuel tank via the fuel return line. The inlet throttle prevents complete compensation from taking place and the pressure
in the valve control chamber drops. As a consequence, the pressure in the valve control chamber is lower than the
pressure in the chamber volume of the nozzle which still has the same level of pressure as the rail. The reduced
pressure in the valve control chamber leads to less pressure being exerted on the control piston and to the injector
needle being opened. Injection commences.
The speed at which the injector needle opens is determined by the difference in throughput in the inlet and outlet
throttle. After a stroke of approx. 200 mm, the control piston reaches its upper limit point and stays there, supported
by a cushion of fuel. The cushion is created by the flow of fuel between the inlet and outlet throttle. The injector nozzle
is now completely open and the fuel is injected into the combustion chamber at a pressure approaching that of the
pressure in the rail.
FUEL DELIVERY SYSTEM – TD6
19-1-14 DESCRIPTION AND OPERATION
At the end of injection, the 2/2 solenoid valve is no longer activated, then the armature is forced downwards by the
force of the valve spring. The ball then closes the outlet throttle. To prevent excessive wear from the contact between
the ball and the valve seat, lodgment, the armature consists of two parts. Although the armature plate is guided
downwards by a cam, it can also oscillate downwards by means of the reset spring, thereby preventing the armature
and ball from being subject to any downward forces. As in the rail, closing the outlet throttle causes pressure to
accumulate in the control compartment through the inlet of the inlet throttle. This increased pressure exerts greater
force on the surface at the head end of the control piston. This force from the valve control chamber and the spring
force exceed the force from the chamber volume, the injector needle closes. The speed at which the injector needle
closes is determined by the throughput of the inlet throttle. Injection stops once the nozzle needle reaches its lower
limit point.
Fuel Filter
The fuel filter is located in the engine compartment on the left hand side.
The fuel filter cleans fuel before the high pressure pump and prevents premature wear to delicate components.
Insufficient filtration can cause damage to pump components, pressure valves and fuel injection nozzles.
To prevent paraffin residue from clogging up the filter at low temperatures, there is a bimetal valve in the return line.
This valve prevents heated fuel residue from mixing with cool fuel from the tank.
Incorporated into the fuel filter is a fuel pressure sensor. This sensor measures the pressure of the fuel being delivered
to the high pressure fuel pump. This enables the ECM to reduce the fuel injection quantity at excessively low inlet
pressures to the point where engine speed and rail pressure are reduced accordingly. The volume required at the inlet
of the high pressure pump is reduced. This makes it possible for the inlet pressure to the high pressure pump to rise
back to the required level.
At an inlet pressure of < 1.5 bar, the high pressure pump can be damaged due to inadequate fill.
Another pump protection feature is that should the inlet pressure difference between the inlet and the return fuel lines
≤ 0.5 bar develops the engine can stall suddenly.
Pressure Relief Valve
The pressure relief valve is located between the fuel filter and the high pressure pump. It is located in the connecting
line between the inlet line before the high pressure pump and the return line after the high pressure pump.
The pressure relief valve limits the inlet pressure to the high pressure pump from 2.0 to between 2.0 and 3.0 bar. This
relieves excess pressure by diverting fuel into the return line. The pressure relief valve protects the high pressure
pump and the secondary pump from overloads.
Fuel Temperature Control
Fuel temperature is controlled by a thermocouple (bimetal valve). If the returning fuel is ≤ 85°C the fuel is returned
directly to the fuel tank. If the returning fuel is ≥ 85ºC the fuel is returned via the fuel cooler. On cold start up the warm
fuel is partial (75%) redirected to the secondary fuel pump which pumps the fuel back into the system to improve cold
starting characteristics.
If the bimetal valve allows the fuel to return to the tank, the fuel flows through a cooler. Cool external air enters the
cooler through a ducted air guide and flows through the fuel cooler. In hotter climate markets there is an electric fan
located in the ducting. The fan assists the fuel cooling by drawing extra air past the cooler thus improving the fuel
cooling characteristics.
FUEL DELIVERY SYSTEM – TD6
DESCRIPTION AND OPERATION 19-1-15
Fuel Cooler
1 Air intake ducting (vehicles without auxiliary
fan)
2 Securing bolt
3 Retaining clip
4 Securing bolt
5 Fuel cooler unit
6 Fan temperature switch
7 Mounting bolt
8 Fuel temperature sensor
9 Air intake ducting (vehicles with auxiliary
cooling fan)
10 Fuel cooler hose
11 Fuel temperature sensor housing
12 Fuel hose
13 Mounting bolt
14 Mounting bracket
15 Nut
16 Front ducting
17 Electric fan (high temperature markets only)
FUEL DELIVERY SYSTEM – TD6
19-1-16 DESCRIPTION AND OPERATION
FUEL DELIVERY SYSTEM – V8
DESCRIPTION AND OPERATION 19-2-1
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FUEL DELIVERY SYSTEM – V8DESCRIPTION AND OPERATION
FUEL DELIVERY SYSTEM – V8
19-2-2 DESCRIPTION AND OPERATION
Fuel Delivery System Component
Location (All Except NAS)
FUEL DELIVERY SYSTEM – V8
DESCRIPTION AND OPERATION 19-2-3
1 Fuel filler cap
2 Fuel pump
3 Fuel tank
4 Fuel filter/pressure regulator
5 Fuel feed pipe
6 Charcoal canister
7 Vapour separator
8 Fuel filler tube
FUEL DELIVERY SYSTEM – V8
19-2-4 DESCRIPTION AND OPERATION
Fuel Delivery System Component
Location (NAS)
FUEL DELIVERY SYSTEM – V8
DESCRIPTION AND OPERATION 19-2-5
1 Fuelling vapour recovery tube
2 Vent tube
3 Fuel pump
4 Vapour separator
5 Fuel tank
6 Fuel filter/pressure regulator
7 Fuel feed pipe
8 Charcoal canister
9 Fuel filler tube
FUEL DELIVERY SYSTEM – V8
19-2-6 DESCRIPTION AND OPERATION
V8 Fuel Delivery System
Fuel Delivery System Components
The Land Rover V8 fuel delivery system comprises the following main components:
l Saddle type fuel tank
l Fuel injectors
l Non return fuel rail
l Fuel pump
l On board refuelling vapour recovery system (NAS only)
l Tank leakage detection system (NAS only).
Fuel Tank
The fuel tank is constructed from moulded plastic and is mounted under the rear seat just forward of the rear axle.
The fuel tank has a 100 Litre capacity and activates a low fuel warning lamp in the instrument pack when there is 12
litres in the tank. The tank is of the saddle tank design with a siphon jet pump in the left side to transfer fuel to the right
side where the fuel pump is mounted. The fuel is delivered along pipes that run along the underside of the vehicle to
a fuel rail mounted on the engine.
Fuel Filter
The fuel filter/pressure regulator is mounted on the lower right hand side of the tank. The charcoal canister is mounted
at the front of the tank on the right hand side. The components are covered by a plastic under tray to protect them
when driving off-road. The undertray has an inspection cover to enable access to the charcoal canister and the fuel
filter.
Fuel Pump
The fuel pump comprises a pump, sender unit, pot and venturi. The unit has an integral filter inside the pot. The pump
unit operates at 3.5 bar for 170–205 l/hr (the V8 has a maximum operating requirement of 90 l/hr).
The pump is controlled by the ECM via the fuel pump relay.
FUEL DELIVERY SYSTEM – V8
DESCRIPTION AND OPERATION 19-2-7
Fuel Pump
Should the fuel pump electrical connection need to be disconnected, it is imperative that the ignition should be
switched off. If the ignition is on in any position the fuel gauge will memorise its last needle position prior to power
down. Once power is restored the gauge will display the last remembered position regardless of the actual level of
fuel in the tank. This will result in incorrect fuel gauge readings if the fuel tank has been drained and not filled worth
exactly the same quantity of fuel that was removed.
Injectors
An electromagnetic, top feed fuel injector is installed in each cylinder inlet tract of the inlet manifolds. A common fuel
rail supplies the injectors with fuel from a returnless fuel delivery system. The fuel in the fuel rail is maintained at a
pressure of 3.5 bar by a pressure regulator incorporated in the fuel filter unit on the side of the fuel tank. A Schraeder
valve is installed in the fuel rail, to the rear of injector No.7, to enable the fuel pressure to be checked.
Injector
FUEL DELIVERY SYSTEM – V8
19-2-8 DESCRIPTION AND OPERATION
Fuel rail
A contoured steel tube common fuel rail, supplies the injectors with fuel from the returnless fuel delivery system. The
fuel in the fuel rail is maintained at a pressure of 3.5 bar by a pressure regulator incorporated into the fuel filter.
Fuel Rail
Tank Leakage Detection (NAS Only)
Tank Leakage Detection Module
New Range Rover is equipped with a tank leakage detection system. The system is controlled by the ECM.
The tank leakage detection module is located inside the wheel arch at the top of the wheel arch next to the fuel filler
neck on a metal bracket.
FUEL DELIVERY SYSTEM – V8
DESCRIPTION AND OPERATION 19-2-9
Leak Detection Normal Operation
1 Throttle plate
2 Air flow to engine
3 Purge valve
4 Charcoal canister
5 Fuel tank
6 Tank leakage detection module
7 Air intake
8 Air filter
9 Change over valve
10 Pump
11 Reference orifice
In its inactive state, filtered fresh air enters the evaporative system through the sprung open valve of the tank leakage
detection module. When the ECM activates the tank leakage detection module for leak testing, it first activates only
the pump motor. This pumps air through a reference orifice (0.5 mm) which causes the electric motor to draw a
specific amperage value. This value is then equivalent to the size of the reference orifice. The solenoid valve is then
energized which seals the EVAP system and directs the pump output to pressurize the EVAP system.
The system is detected as having a large leak if the amperage value is not realized, a small leak if the same reference
amperage is realized or no leak if the amperage value is higher than the reference leak value.
The leak detection module ensures accurate fuel system leak detection for leaks as small as 0.5mm. The pump
contains an integral DC motor which is activated directly by the engine control module. The ECM monitors the pump
motor operating current as the measurement for detecting leaks.
In its inactive state the pump motor and the change over valve of the DC Motor LDP are not energized. When purge
valve operation occurs filtered air enters the fuel system compensating for engine vacuum drawing on the
hydrocarbon vapours stored in the charcoal canister.
M
M19 3566
0.5mm
1
3
2
4
5
6
7
8
9
10
11
FUEL DELIVERY SYSTEM – V8
19-2-10 DESCRIPTION AND OPERATION
The ECM only initiates a leak diagnosis test every second time the criteria are met. The criteria are as follows:
l Engine OFF with ignition switched OFF
l Engine Control Module still in active state or what is known as “follow up mode ”(Main Relay energized, control
module and ECM components on-line for extended period after key off)
l Prior to Engine/Ignition switch OFF condition, vehicle must have been driven for a minimum of 20 minutes
l Prior to minimum 20 minute drive, the vehicle must have been OFF for a minimum of 5 hours
l Fuel Tank Capacity must be between 15 and 85% (safe approximation between 1/4 - 3/4 of a tank)
l Ambient Air Temperature between -7°C & 35°C (20°F & 95°F )
l Altitude < 2500m (8,202 feet)
l Battery Voltage between 11.5 and 14.5 Volts.
When these criteria are satisfied every second time, the ECM will start the Fuel System Leak Diagnosis Test. The test
will typically be carried out once a day i.e. once after driving to work in the morning, when driving home in the evening
the criteria are once again met but the test is not initiated. The following morning, the test will run again.
Phase 1 - Reference Measurement
1 Throttle plate
2 Air flow to engine
3 Purge valve
4 Charcoal canister
5 Fuel tank
6 Tank leakage detection module
7 Air intake
8 Air filter
9 Change over valve
10 Pump
11 Reference orifice
The ECM activates the pump motor. The pump pulls air from the filtered air inlet and passes it through a precise
0.5mm reference orifice in the pump assembly.
The ECM simultaneously monitors the pump motor current flow. The motor current raises quickly and levels off
(stabilizes) due to the orifice restriction. The ECM stores the stabilized amperage value in memory. The stored
amperage value is the electrical equivalent of a 0.5 mm (0.020 ”) leak.
M
M19 3579
0.5mm
1
3
2
4
5
6
7
8
9
10
11
FUEL DELIVERY SYSTEM – V8
DESCRIPTION AND OPERATION 19-2-11
Phase 2 - Leak Detection
1 Throttle plate
2 Air flow to engine
3 Purge valve
4 Charcoal canister
5 Fuel tank
6 Tank leakage detection module
7 Air intake
8 Air filter
9 Change over valve
10 Pump
11 Reference orifice
The ECM energizes the Change Over Valve allowing the pressurized air to enter the fuel system through the Charcoal
Canister. The ECM monitors the current flow and compares it with the stored reference measurement over a duration
of time.
Once the test is concluded, the ECM stops the pump motor and immediately de-energizes the change over valve.
This allows the stored pressure to vent thorough the charcoal canister trapping hydrocarbon vapour and venting air
to atmosphere through the filter.
M
M19 3580
0.5mm
1
3
2
4
5
6
7
8
9
10
11
FUEL DELIVERY SYSTEM – V8
19-2-12 DESCRIPTION AND OPERATION
Test Results
A = Current stabilises
B = Current drops
C = Current rises
D = No leak detected
E = 0.5mm leak
F = Leak >1.0mm
G = Change over valve energised
H = Pump motor energised
I = Motor current-Pressure
J = Reference measurement 0.5mm
K = Time duration
The time duration varies between 45 & 270 seconds depending on the resulting leak diagnosis test results (developed
tank pressure “amperage ”within a specific time period). However the chart above depicts the logic used to determine
fuel system leaks.
M19 3581
A B C
G
H
D
E
F
I
K
J
COOLING SYSTEM – TD6
DESCRIPTION AND OPERATION 26-1-1
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COOLING SYSTEM – Td6DESCRIPTION AND OPERATION
COOLING SYSTEM – TD6
26-1-2 DESCRIPTION AND OPERATION
Td6 Cooling System – Sheet 1 of 2
A = Heater matrix, B = Coolant elbow
COOLING SYSTEM – TD6
DESCRIPTION AND OPERATION 26-1-3
1 Coolant rail
2 Hose – Coolant rail to engine oil cooler
3 Clip
4 Hose – Expansion tank return
5 Radiator top hose
6 Hose – Coolant/air bleed to expansion tank
7 Hose – Radiator to transmission cooler
8 Radiator bottom hose
COOLING SYSTEM – TD6
26-1-4 DESCRIPTION AND OPERATION
Td6 Cooling System – Sheet 2 of 2
A = Heater matrix, B = Coolant elbow
COOLING SYSTEM – TD6
DESCRIPTION AND OPERATION 26-1-5
1 Hose – Changeover valve to Fuel Burning
Heater (FBH)
2 Clip
3 Hose – FBH to auxiliary coolant pump
4 Hose – Auxiliary coolant pump to coolant valve
5 Clip
6 Clip
7 Hose – Coolant valve to heater assembly
8 Clip
9 Hose – Coolant valve to heater assembly
10 Clip
11 Hose – Coolant outlet elbow to changeover
valve
12 Clip
13 Hose – Coolant rail to heater assembly
COOLING SYSTEM – TD6
26-1-6 DESCRIPTION AND OPERATION
Td6 Coolant Flow
A and B = Heater matrix to engine coolant connections
COOLING SYSTEM – TD6
DESCRIPTION AND OPERATION 26-1-7
1 Hose – Coolant outlet elbow to changeover
valve
2 Hose – Coolant rail to heater assembly
3 Bulkhead connections
4 Hose – Coolant valve to heater assembly
5 Fuel Burning Heater (FBH)
6 Coolant elbow
7 Coolant rail
8 Radiator top hose
9 Expansion tank
10 Hose – Coolant rail to engine oil cooler
11 Oil cooler
12 Hose – Coolant/air bleed to expansion tank
13 Hose – Expansion tank return
14 Transmission oil cooler
15 Hose – Radiator to transmission oil cooler
16 Radiator bottom hose
17 Thermostat housing
18 Exhaust Gas Recirculation (EGR) cooler
19 Hose – FBH to auxiliary coolant pump
20 Auxiliary coolant pump
21 Hose – Auxiliary coolant pump to coolant valve
22 Hose – Coolant valve to heater assembly
23 Coolant valves
24 Changeover valve
COOLING SYSTEM – TD6
26-1-8 DESCRIPTION AND OPERATION
Description
General
The cooling system employed is the bypass type, which allows coolant to circulate around the engine and the heater
circuit while the thermostat is closed. The primary function of the cooling system is to maintain the engine within an
optimum temperature range under changing ambient and engine operating conditions. Secondary functions are to
provide heating for the passenger compartment and cooling the engine oil, Exhaust Gas Recirculation (EGR) system
and transmission fluid. The cooling system comprises:
l Radiator
l Passenger compartment heater matrix
l Integrated Oil Cooler and Filter Assembly
l Coolant pump
l Thermostat
l Expansion tank
l Viscous cooling fan
l Electric cooling fan
l Connecting hoses and pipes
l Fuel Burning Heater (FBH).
The coolant is circulated by a centrifugal type pump mounted on the front of the engine and driven by the ancillary
drive 'polyvee' belt. The coolant pump circulates coolant around the cylinder block and cylinder head, to the radiator,
integrated oil cooler and filter assembly, the heater matrix and the transmission fluid coolers, via the coolant hoses
and pipes.
The thermostat is integral to the coolant pump housing on the inlet side of the cooling circuit. This provides a more
stable control of the coolant temperature in the engine.
The radiator is a cross flow type with an aluminium matrix. The bottom of the radiator is located in rubber bushes
supported by plastic brackets which are clipped into the body longitudinals. The top of the radiator is located in rubber
bushes secured by brackets fitted to the bonnet locking platform.
The radiator top hose is connected to a coolant outlet pipe which is bolted to the centre of the cylinder head. The elbow
also has a connection for the feed to the heater matrix via a flexible hose.
The radiator bottom hose is connected to the inlet side of the coolant pump housing.
An expansion tank is fitted forward of the LH suspension turret in the engine compartment. The expansion tank allows
for expansion of the coolant when the engine is hot and replaces the coolant into the system as the engine cools down.
The Fuel Burning Heater (FBH) is located below the battery. The unit is connected in series with the coolant supply
to the heater matrix.
+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Description.
For additional airflow through the radiator matrix, particularly when the vehicle is stationary, two cooling fans are fitted.
A viscous fan is attached to the coolant pump pulley at the front of the engine. The fan is attached to a threaded spigot
on the pulley with a left hand threaded nut. The fan draws air through the radiator to assist in cooling when the vehicle
is stationary.
An electric fan controlled by the Electronic Diesel Control (EDC) system is fitted in front of the radiator assembly. It is
controlled by the Engine Control Module (ECM) via a cooling fan ECU. The cooling fan ECU is located behind the
radiator, below the bonnet closing panel. The temperature of the cooling system is monitored by the ECM via signals
from an Engine Coolant Temperature (ECT) sensor, which is mounted at the rear of the cylinder head.
Operation
With the engine running, the coolant pump pulley is driven by the ancillary drive belt. When the engine is cold, the
thermostat is closed and coolant is prevented from circulating through the radiator. Coolant is able to circulate through
the bypass, heater matrix and coolers.
COOLING SYSTEM – TD6
DESCRIPTION AND OPERATION 26-1-9
As the temperature increases, at 88 °C (190 °F) the thermostat begins to open, bleeding cool fluid from the radiator
bottom hose through the pump and into the cylinder block. This allows hot coolant to flow from the cylinder block to
the radiator through the top hose, balancing the flow of hot and cold fluid to maintain the optimum operating
temperature. When the thermostat opens fully, the full flow of coolant passes through the radiator.
The increased coolant volume, created by heat expansion, is directed to the expansion tank through a bleed hose
from the top of the radiator. The expansion tank has an outlet hose which is connected into the coolant circuit. This
outlet hose returns the coolant to the system when the engine cools.
Coolant flows through the radiator from the top right hand tank to the bottom left hand tank and is cooled by air passing
through the matrix. The temperature of the cooling system is monitored by the ECM via a temperature sensor located
in the cylinder head. The ECM uses signals from this sensor to control the cooling fan operation and adjust fuelling
according to engine temperature.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
To control the cooling fan, the ECM sends a Pulse Width Modulated (PWM) signal to the cooling fan ECU. The
frequency of the PWM signal, which is varied by the ECM, is used by the ECU to determine the output voltage supplied
to the fan motors.
The ECM operates the fan in response to inputs from the ECT sensor, the air conditioning (A/C) switch and the A/C
pressure sensor.
+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Operation.
The speed of the electric cooling fan is also influenced by vehicle road speed. The ECM adjusts the speed of the
cooling fan, to compensate for the ram effect of vehicle speed, using the CAN bus road speed signal received from
the ABS ECU.
When the engine is switched off, the ECM maintains the cooling fans in an active condition for up to 8 minutes. If the
temperature does not reach a predetermined value within 4 minutes, the ECM will terminate the active period. If the
fans are active and the temperature falls below a predetermined value, the ECM will terminate further fan operation.
COOLING SYSTEM – TD6
26-1-10 DESCRIPTION AND OPERATION
COOLING SYSTEM – V8
DESCRIPTION AND OPERATION 26-2-1
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COOLING SYSTEM – V8DESCRIPTION AND OPERATION
COOLING SYSTEM – V8
26-2-2 DESCRIPTION AND OPERATION
V8 Cooling System – Sheet 1 of 2
A and B = Heater matrix
COOLING SYSTEM – V8
DESCRIPTION AND OPERATION 26-2-3
1 Radiator bottom hose
2 Radiator top hose
3 Hose – Coolant/air bleed to expansion tank
4 Hose – Alternator housing
5 Hose – Expansion tank to coolant valve
6 Hose – Coolant valve to water pump
COOLING SYSTEM – V8
26-2-4 DESCRIPTION AND OPERATION
V8 Cooling System – Sheet 2 of 2
A and B = Heater matrix
COOLING SYSTEM – V8
DESCRIPTION AND OPERATION 26-2-5
1 Hose – Changeover valve to Fuel Burning
Heater (FBH)
2 Hose – FBH to auxiliary coolant pump
3 Hose – Coolant valve to heater assembly
4 Hose – Auxiliary coolant pump to coolant valve
5 Hose – Coolant valve to heater assembly
6 Hose – Engine to changeover valve
7 Hose – Engine to heater assembly
COOLING SYSTEM – V8
26-2-6 DESCRIPTION AND OPERATION
V8 Coolant Flow – Models With FBH
A and B = Heater matrix to engine coolant connections
COOLING SYSTEM – V8
DESCRIPTION AND OPERATION 26-2-7
1 Fuel Burning Heater (FBH)
2 Hose – Changeover valve to FBH
3 Hose – FBH to auxiliary coolant pump
4 Bulkhead connections
5 Coolant manifold
6 Expansion tank
7 Hose – Coolant/air bleed to expansion tank
8 Hose – Expansion tank to coolant valve
9 Water cooled alternator housing
10 Hose – Radiator
11 Transmission oil cooler
12 Radiator
13 Radiator bottom hose
14 Hose – Coolant valve to water pump
15 Thermostat housing
16 Auxiliary coolant pump
17 Hose – Coolant valve to heater assembly
18 Coolant valve
19 Changeover valve
20 Hose – Engine to heater assembly
21 Hose – Engine to changeover valve
COOLING SYSTEM – V8
26-2-8 DESCRIPTION AND OPERATION
Description
General
The cooling system employed is the bypass type, which allows coolant to circulate around the engine and the heater
circuit while the thermostat is closed. The primary function of the cooling system is to maintain the engine within an
optimum temperature range under changing ambient and engine operating conditions. Secondary functions are to
provide heating for the passenger compartment and cooling for the transmission fluid. The cooling system comprises:
l Radiator
l Passenger compartment heater matrix
l Transmission fluid cooler
l Coolant pump
l Thermostat
l Expansion tank
l Viscous cooling fan
l Electric cooling fan
l Connecting hoses and pipes
l Fuel Burning Heater (FBH) – selected markets only
l Liquid cooled alternator housing.
The coolant is circulated by a centrifugal type pump mounted on the front of the engine and driven by an ancillary
drive 'polyvee' belt. The coolant pump circulates coolant through the cylinder block and the cylinder heads via a
chamber located in the 'vee' of the engine. Having passed through the engine, the coolant returns via a rear-mounted
manifold that features the connections for the heater matrix and through pipes running in the 'vee' of the engine to the
coolant pump. The coolant pump also circulates coolant to the radiator-mounted transmission fluid cooler and the
liquid cooled alternator housing via flexible hoses.
The die-cast coolant pump, driven by an ancillary drive belt, is fitted to the timing case cover. It contains the dual
coolant temperature sensor and the electrically heated 'map controlled' thermostat controlled by the engine
management system.
The map controlled thermostat incorporates a heating element inside a conventional expanding wax thermostat core
which enables the engine management system to 'power' the thermostat open when the engine is under full load and/
or high output conditions. This provides sufficient cooling reserve through anticipation of the thermal load whilst
allowing the engine to run at higher operating temperatures under part load conditions.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
The radiator is a cross flow type with an aluminium matrix and has a drain tap on the lower left hand rear face. The
bottom of the radiator is located in rubber bushes supported by plastic brackets which are clipped into the body
longitudinals. The top of the radiator is located in rubber bushes secured by brackets fitted to the bonnet locking
platform.
The radiator top and bottom hoses are connected to the outlet and inlet sides of the coolant pump housing
respectively.
An expansion tank is fitted forward of the LH suspension turret in the engine compartment. The expansion tank allows
for expansion of the coolant when the engine is hot and replaces the coolant into the system as the engine cools down.
The liquid cooled transmission fluid cooler is mounted on the plastic radiator support adjacent to the lower right hand
rear of the matrix and receives coolant from either the bottom of the radiator or the return elbow pipe between the
coolant pump and the radiator as required.
The Fuel Burning Heater (FBH) is located below the battery. The unit is connected in series with the coolant supply
to the heater matrix.
+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Description.
For additional airflow through the radiator matrix, particularly when the vehicle is stationary, two cooling fans are fitted;
one being driven by the engine via the coolant pump drive shaft and one being driven by an integral electric motor.
CAUTION: The fan is attached to a threaded spigot on the pulley with a left hand thread.
COOLING SYSTEM – V8
DESCRIPTION AND OPERATION 26-2-9
The engine driven fan contains a viscous coupling that allows the fan to slip as the engine speed increases. The fan
is attached to a threaded spigot on the pulley with a left hand threaded nut. The fan draws air through the radiator to
assist in cooling when the vehicle is stationary.
An electric fan controlled by the engine management system is fitted in front of the radiator assembly.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
Operation
With the engine running, the coolant pump pulley is driven by an ancillary drive belt. When the engine is cold, the
thermostat is closed and coolant is prevented from circulating through the radiator. Coolant is able to circulate through
the engine and the passenger compartment heater matrix via a thermostat bypass.
As the temperature increases the thermostat begins to open, allowing cool fluid to be drawn from the radiator bottom
hose through the pump and into the cylinder block and hot coolant to flow from the coolant pump housing to the
radiator via the radiator top hose, where it is cooled by air passing through the matrix. When the thermostat opens
fully, the full flow of coolant passes through the radiator.
Coolant is also drawn through the liquid cooled transmission fluid cooler and the liquid cooled alternator housing by
the coolant pump via the coolant circuit.
The increased coolant volume, created by heat expansion, is directed to the expansion tank through a bleed hose
from the top of the radiator. The expansion tank has an outlet hose which is connected into the coolant circuit. This
outlet hose returns the coolant to the system when the engine cools.
COOLING SYSTEM – V8
26-2-10 DESCRIPTION AND OPERATION
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-1
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MANIFOLDS AND EXHAUST SYSTEM – Td6DESCRIPTION AND OPERATION
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-2 DESCRIPTION AND OPERATION
Exhaust Manifold Component Layout
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-3
1 Heat shield
2 Bolt – Turbocharger to exhaust manifold (3 off)
3 Exhaust manifold
4 Nut – Exhaust manifold to cylinder head (12 off)
5 Gasket – Exhaust manifold to turbocharger
6 Gasket – Exhaust manifold to cylinder head (3
off)
7 Turbocharger
8 Stud
9 Banjo bolt – Oil feed pipe
10 Washer
11 Oil feed pipe
12 Turbocharger support bracket
13 Turbocharger mounting bolt (3 off)
14 Banjo bolt – Oil feed pipe
15 Washer
16 Hose – Turbocharger oil drain
17 Clamp
18 Oil drain pipe
19 Bolt – Oil drain pipe to turbocharger
20 Gasket – Oil drain pipe to turbocharger
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-4 DESCRIPTION AND OPERATION
Inlet Manifold Component Layout
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-5
1 Bolt and compression limiter (12 off)
2 Rubber inserts (5 off)
3 Sensor – Manifold Absolute Pressure (MAP)
4 Bolt – MAF sensor to inlet manifold
5 Inlet manifold
6 Clip
7 Gasket (6 off)
8 Seal (7 off)
9 Seal (6 off)
10 Spacer (7 off)
11 Nut (7 off)
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-6 DESCRIPTION AND OPERATION
Exhaust System Component Layout
X = Cut point
M30 1152
1
4
2
6
7
8
9
8
9
3
5
5
3
8
9
7
15
11
11
12
13
13
14
11
16
10
X
X
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-7
1 Exhaust Manifold
2 Turbocharger
3 Nut - Turbocharger to exhaust pipe
4 Pre-catalytic converter
5 Bolt-Exhaust front pipe to exhaust
6 Catalytic Converter
7 Mounting bracket - middle
8 Mounting brackets - rear (2 off)
9 Mounting brackets - rear (2 off)
10 Rear silencer
11 Nut - Mounting brackets (10 off)
12 Mounting bracket - Rear
13 Mounting rubber- Rear
14 Mounting rubber - Rear
15 Mounting bracket - Rear
16 Repair sleeve
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-8 DESCRIPTION AND OPERATION
Description
General
The inlet manifold directs cooled and compressed air from the turbocharger and intercooler into the cylinders, where
it is mixed with fuel from the injectors. Exhaust gases from the exhaust manifold can also be directed into the inlet
manifold via a pipe from the exhaust manifold and an Exhaust Gas Regulator (EGR) valve on the inlet manifold. The
exhaust manifold allows combustion gases from the cylinders to leave the engine where they are directed into the
turbocharger and exhaust system.
The exhaust system is attached to the turbocharger and is directed along the underside of the vehicle to emit exhaust
gases from the tail pipes located at the rear of the vehicle.
Intake Assembly
1 Upper Timing Chain Cover
2 Air Filter
3 Oil filler aperture
4 Camshaft Cover
5 Oil Depression Limiter
6 Oil Depression Limiter
7 Inlet Manifold
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-9
Inlet Manifold
The inlet manifold is a one piece plastic moulding with inlet tracts feeding intake air into the cylinder head ports directly
in the cylinder head via the camshaft cover. The manifold is secured to the cylinder using seven studs. All incorporate
sealing washers and compression limiters.
The manifold is secured to the camshaft cover with twelve bolts incorporating compression limiters. Sealing between
the manifold, cylinder head, and camshaft cover is achieved using moulded rubber seals located in recesses in the
manifold.
A boost pressure sensor is located on the rear of the inlet manifold. The sensor is secured to the manifold with a bolt
and sealed with an 'O' ring. On the front of the inlet manifold, four threaded holes provide for the attachment of the
EGR valve. The valve is sealed to the manifold with an 'O' ring.
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-10 DESCRIPTION AND OPERATION
Intercooler
Intercooler
1 Inlet Air
2 Unfiltered air inlet
3 Intake silencer and filter
4 Sensor - Manifold Absolute Pressure (MAP)
5 Intake manifold
6 EGR Valve
7 Cooled air to inlet manifold
8 Bypass hose
9 Intake air to turbocharger
10 Intercooler
11 Compressed air from turbocharger
12 Turbocharger
13 Exhaust front pipe
M00 0000
1
2
2
5
6
7
4
3
8
9
13
12
11
10
M30 1151
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-11
The intercooler is mounted below the radiator, and receives compressed air from the turbocharger. By cooling the
compressed air, the intercooler further increases the mass of air delivered to the inlet manifold.
Exhaust Manifold
The cast iron exhaust manifold is secured to the cylinder head using twelve studs with nuts. Three metal gaskets seal
the manifold to the cylinder head.
A flanged connection on the underside of the manifold provides for the attachment of the turbocharger. The
turbocharger is attached to the flange with three bolts and sealed with a metal gasket.
A second flange, located on the front of the manifold provides the connection point for the EGR pipe. The pipe flange
is secured to the manifold with two bolts. There is no gasket between the EGR pipe and the exhaust manifold.
Exhaust Gas Recirculation (EGR)
The EGR system directs exhaust gases into the inlet manifold to be used in the combustion process. The principal
effect of this is to reduce combustion temperatures, which in turn reduces Nitrous Oxide (NOx) emissions.
The aluminium EGR valve is fitted at the inlet to the intake manifold. It is supplied by cooled air via the intercooler.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-12 DESCRIPTION AND OPERATION
Turbocharger
Turbocharger
1 Compressor
2 Driveshaft
3 Adjustment ring
4 Guide vanes
5 Turbine
6 Exhaust outlet
7 Exhaust gas from engine
8 Bearing housing
9 Air to intercooler
10 Air from intake silencer
The turbocharger is secured to the exhaust manifold by three bolts, and to the front part of the exhaust system by two
studs and lock nuts. The turbocharger utilises a Variable Nozzle Turbine (VNT), with a boost pressure of up to 2.1
bar. The VNT makes it possible to vary the exhaust gas flow of the turbine dependent on engine operation. Variable
turbine geometry facilitates better use of the exhaust gas energy so as to further improve the efficiency of the
turbocharger when compared to the more conventional wastegate control.
M30 1156
1
2
3
4
5
8
6
7
9
10
MANIFOLDS AND EXHAUST SYSTEM – TD6
DESCRIPTION AND OPERATION 30-1-13
1 Exhaust turbine
2 Guide vanes
3 Guide vane – Open
4 Guide vane – Closed
Closing the guide vanes on the VNT results in a reduction of exhaust gas flow and an increase in the flow rate of
exhaust gas to the turbine wheel. This improves the power transfer to the turbine wheel and compressor, particularly
at low engine speeds, thus increasing boost pressure. The guide vanes are opened progressively as engine speed
increases so that power transfer always remains in balance with the required charger speed and the required boost
pressure level.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
M30 1150
4
3
2
1
MANIFOLDS AND EXHAUST SYSTEM – TD6
30-1-14 DESCRIPTION AND OPERATION
Exhaust System
The stainless steel exhaust system is supplied as a one-piece assembly and is connected to the turbocharger exhaust
stub pipe flange by two screws and hexagonal nuts. It is attached to the underside of the body with five rubber
mountings.
It consists of a stub pipe, a catalytic converter, a single intermediate pipe which divides into two branch pipes, before
joining the single rear silencer assembly. Internally the rear silencer assembly is divided into two independent
silencers each with its own tailpipe. The tailpipes are bent downwards and not normally visible.
Although supplied as a one-piece assembly, in service, sections of the system can be replaced individually. Service
joints, identified by indentations on the pipes, show where the exhaust pipes can be cut to accommodate replacement
sections.
After the replacement sections are positioned the system integrity is restored by sealing the service joints with one
piece sleeves.
MANIFOLDS AND EXHAUST SYSTEM – V8
DESCRIPTION AND OPERATION 30-2-1
MANIFOLDS AND EXHAUST SYSTEM – V8DESCRIPTION AND OPERATION
Exhaust Manifold Component Layout
1 Exhaust Manifold – Cylinders 1 – 4
2 Nut – (16 off)
3 Stud – Manifold to Exhaust Pipe — (4 off)
4 Gasket – cylinders 3 – 4
5 Gasket – cylinders 1 – 2, 5 – 6 and 7 – 8
6 Exhaust Manifold – Cylinders 5 – 8
MANIFOLDS AND EXHAUST SYSTEM – V8
30-2-2 DESCRIPTION AND OPERATION
Inlet Manifold Component Layout
MANIFOLDS AND EXHAUST SYSTEM – V8
DESCRIPTION AND OPERATION 30-2-3
1 Gasket
2 Vent Pipe
3 Cover bolt
4 Supporting ring
5 Cap
6 Connector
7 Plug
8 Clip
9 O-ring Seal
10 Gasket
11 Manifold intake assembly
12 Gasket
13 Gasket
14 Bolt
15 Front Cover
16 Gasket
17 Compression limiter
18 Intake manifold nuts
MANIFOLDS AND EXHAUST SYSTEM – V8
30-2-4 DESCRIPTION AND OPERATION
Exhaust System Component Layout
X = Forward cut point; Y = Rear cut point
M30 1153
1
2
5
6
7 9
4
7
5
6
8
11
12
13
11
14
14
15
14
16
14
15
4
7
3
3
10
14
3
10
11
17
7
x
x
y
y
MANIFOLDS AND EXHAUST SYSTEM – V8
DESCRIPTION AND OPERATION 30-2-5
1 Left manifold
2 Right manifold
3 Exhaust flange nuts
4 Pre-catalyst Heated Oxygen Sensor (HO2S)
5 Pre-catalyst
6 Main catalyst
7 Main Catalyst Heated Oxygen Sensor (HO2S)
8 Left front pipe
9 Right front pipe
10 Mass Damper
11 Mounting bracket (2 off)
12 Front silencer assembly
13 Rear pipe
14 Mounting bracket (4 off)
15 Tailpipe
16 Rear silencer assembly
17 Repair sleeve
MANIFOLDS AND EXHAUST SYSTEM – V8
30-2-6 DESCRIPTION AND OPERATION
Description
General
The inlet manifold on the V8 engine is located on the top of the engine, between the cylinders.
The two exhaust manifolds, one for each bank of four cylinders, directs the engine combustion gases from the
cylinders to the exhaust system.
The exhaust system consists of two identical systems, sharing a common rear silencer assembly, connected to each
exhaust manifold. Two catalytic converters are located in each of the front pipes from it's respective manifold and a
silencer is installed midway along the system.
Inlet Manifold
The inlet manifold is a light weight, one piece plastic moulding. The manifold is acoustically decoupled from the
cylinder heads to reduce noise and vibrations.
The throttle plate has two wedges screwed directly to it, these provide a curved zone for smoother throttle response
during idle, off-idle transition.
The combined output of the mixing plate ensures that the intake air is evenly distributed among all the cylinders, which
can improve idle quality.
Exhaust Manifold
Two handed, double skinned stainless steel sheet metal manifolds are used on the V8 engine. Each manifold has four
ports which merge into one flanged outlet positioned centrally on the manifold.
Each manifold is secured to its cylinder head using eight studs with nuts and sealed with two gaskets. The flanged
outlet on each manifold provides the attachment for the exhaust system.
NOTE: The exhaust manifold gasket for cylinders 3–4 is not interchangeable with the gaskets for cylinders 1–2, 5–6
or 7–8.
Exhaust System
The stainless steel exhaust system is supplied as a one-piece assembly.
It consists of two stub pipes and pre-catalytic converter HO2S, two intermediate catalytic converters, two main
catalytic converters and down pipes, each with a post catalytic converter HO2S, two intermediate silencer assemblies
and pipes joining the single rear silencer assembly. Internally the rear silencer assembly is divided into two
independent silencers, each with its own tailpipe. The tail pipes are bent downwards and not normally visible.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
The exhaust system is attached to the underside of the body with five rubber mountings and a mass damper. The
mass damper is fitted forward of the right intermediate silencer.
Although supplied as a one-piece assembly, in service, sections of the system can be replaced individually. Service
joints, identified by indentations on the pipes, show where the exhaust pipes can be cut to accommodate replacement
sections.
After the replacement sections are positioned the system integrity is restored by sealing the service joints with one
piece sleeves. For more information, refer to the Service Procedures Workshop manual.
TRANSFER BOX
DESCRIPTION AND OPERATION 41-1
TRANSFER BOXDESCRIPTION AND OPERATION
Transfer Box Component Location
1 Instrument pack
2 Low range warning lamp
3 Selector lever assembly
4 High/low range selection switch
5 Transfer box
6 Transfer box ECU
TRANSFER BOX
41-2 DESCRIPTION AND OPERATION
Transfer Box Exploded View
TRANSFER BOX
DESCRIPTION AND OPERATION 41-3
1 Sun gear
2 Thrust washer
3 Planetary gear set assembly
4 Inner blocker ring
5 Cone
6 Detente (3 off)
7 Outer blocker ring
8 Hub - synchroniser
9 Sleeve - synchroniser
10 Outer blocker ring
11 Cone
12 Input shaft assembly
13 Main shaft
14 Thrust washer
15 Drive sprocket assembly
16 Torsen® differential assembly
17 Fork and rail assembly
18 Chain
19 Front output shaft assembly
20 Bolt (23 off)
21 Flange assembly - rear output
22 Flange O-ring
23 Flange nut
24 Actuator assembly
25 Thrust bearing (2 off)
26 Lead screw
27 Filler/level plug
28 Seal
29 Drain plug
30 Seal
31 Filter screen
32 Chip collector magnet
33 Connector tube
34 Pump feed tube
35 O-ring seal
36 Dowel (2 off)
37 Oil pump assembly
38 Rear casing assembly
39 Front output flange assembly
40 Flange O-ring
41 Flange nut
42 Mounting bush
43 Input seal
44 Retaining ring
45 Front casing assembly
46 Vent assembly
47 Pinion thrust washer (8 off)
48 Roller separator ring (12 off)
49 Pinion planet roller (144 off)
50 Planet pinion shaft (4 off)
51 Planet pinion gear (4 off)
TRANSFER BOX
41-4 DESCRIPTION AND OPERATION
Transfer Box Control Diagram
A = Hardwired connection; C = Diagnostic DS2 bus; D = CAN Bus
M41 7838A
A
8
6
5
3
4
2
7
11
D
9
10
1
C
TRANSFER BOX
DESCRIPTION AND OPERATION 41-5
1 High/Low range selection switch
2 EAT ECU
3 Engine Control Module (ECM)
4 Actuator potentiometer
5 Actuator
6 Fuse 33 Ignition feed
7 Fusible link Permanent battery feed
8 Fuse 37 Neutral selection
9 Ignition switch
10 Diagnostic socket
11 Transfer box ECU
TRANSFER BOX
41-6 DESCRIPTION AND OPERATION
Description
General
The NV225 Transfer Box is a full time, permanent four wheel drive, torque splitting transmission with equal torque
distribution to the front and rear propeller shafts. The transfer box has the following features:
l Permanent four wheel drive with 50/50 torque split
l Two speed, fully synchronised 'shift on the move' system with electronic control and operation
l High range direct drive and low range via epicyclic gearset
l Torsen® Type B torque sensing and torque biasing centre differential
l Self lubricating oil pump system.
The transfer box is located under the vehicle in a subframe, behind the transmission. The units used on both the Td6
and V8 variants are identical, with the exception of the large mounting bush. The transfer box is manufactured by New
Venture Gear in Roitzsch, Germany.
The transfer box receives an input from the transmission output shaft which is passed through the unit to two outputs
for the front and rear propeller shafts.
The transfer box provides full time four wheel drive via a 50:50 torque sensing Torsen® differential. The unit design
allows “shift on the move” from high to low range and visa versa. A planetary gearset with helical planetary pinion
gears provides low range operation. When in low range, the planetary gearset provides a ratio of 2.69:1 which gives
the vehicle an extremely low, low range crawl speed. High range is a direct drive from the transmission output shaft
and provides a 1:1 ratio.
The transfer box has electronic control, via a PWM actuator (DC motor), on the shift from high to low range. The
actuator is controlled by a transfer box ECU, which is located behind the battery in the engine compartment.
TRANSFER BOX
DESCRIPTION AND OPERATION 41-7
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TRANSFER BOX
41-8 DESCRIPTION AND OPERATION
Transfer Box – Sectional View
M41 7837
A
A
40
37
14
1
A - A
19
18
17
16
15
13
12
11
8
6
7
9
5
4
10
34
33
32
30
26
25
24
29
36
23
22
21
20
3
2
31
38
39
28
27
35
TRANSFER BOX
DESCRIPTION AND OPERATION 41-9
1 Dowel (2 off)
2 Bolt (23 off)
3 Thrust washer
4 Rear casing assembly
5 Oil pump assembly
6 Rear output flange assembly
7 Main shaft
8 Flange nut
9 Flange O-ring
10 Drive sprocket assembly
11 Actuator assembly
12 Lead screw
13 Thrust bearing (2 off)
14 Chain
15 Chip collector magnet
16 Filter screen
17 Connector – pump feed tube
18 Pump feed tube
19 O-ring seal
20 Flange O-ring
21 Flange nut
22 Front output shaft assembly
23 Front output flange assembly
24 Fork and rail assembly
25 Outer blocker ring
26 Sleeve - synchroniser
27 Thrust washer
28 Sun gear
29 Retaining ring
30 O-ring seal
31 Hub - synchroniser
32 Input shaft assembly
33 Input seal
34 Planetary gearset assembly
35 Inner blocker ring
36 Cone
37 Front casing assembly
38 Outer blocker ring
39 Detente (3 off)
40 Torsen® differential assembly
TRANSFER BOX
41-10 DESCRIPTION AND OPERATION
The major components of the transfer box are; the front casing assembly, the rear casing assembly, the planetary
gearset, the Torsen® differential, the fork and rail assembly and the actuator assembly.
The front and rear casing assemblies are manufactured from cast aluminium. Fins are cast into the front casing to aid
heat dissipation. Both casing assemblies are bolted together and provide the bearing locations for the main shaft, the
Torsen® differential and the planetary gearset. The rear casing provides the attachment location for the actuator
assembly.
An oil pump assembly is located in the rear casing and is driven by a splined coupling on the main shaft. The pump
has an oil tube to the bottom of the two casings with a filter screen to collect particulate matter. A magnet is located
below the filter screen to collect any metallic particulate matter. The oil pump provides a pressurised supply to a drilling
in the centre of the main shaft. Cross-drillings in the main shaft provide lubrication for the bearings and rotary
components.
Mass Damper (Td6 models only)
On Td6 engine models, a mass damper is fitted to the front casing assembly. The damper is located next to the front
output flange and secured to the casing with bolts. The damper absorbs vibration and resonance inherent with diesel
engines, reducing passenger compartment noise and vibration.
The front casing assembly houses a mounting bush which differs in its material between engine variants. The bushes
are identified by a colour code; red is for V8 engine models and blue is for Td6 engine models. The construction of
the bushes is visually identical. The material from which the bushes are constructed differs to absorb the differing
vibrational frequencies between the engine variants.
Drive is passed from the input shaft and via the Torsen® differential to the mainshaft and the drive sprocket assembly.
The mainshaft rotates and passes the rotational motion to the rear propshaft. The drive sprocket assembly rotates
and passes this rotation, via the chain, to the front propshaft. The drive sprocket carries a 3/8” pitch drive chain which
drives a sprocket which is integral with the front output shaft. Because both sprockets are the same, with the same
number of drive teeth, the rotational motion of the drive sprocket is identical to that of the front output shaft sprocket.
The 50:50 torque output ratio is produced from the Torsen® differential unit. This unit can drive the output to the main
shaft and the drive sprocket assembly at a 50:50 ratio during normal driving conditions.
The transfer box requires a unique oil developed with NVG and Burmah-Castrol specifically for the Land Rover
transfer box. The oil is a fully synthetic with the following specification: BOT 26 FMB 1 75W-90. The oil contains unique
additives which enhance the transfer box operation. No other oil must be used in the transfer box.
Should the transfer box require repair, the only serviceable items are the input and two output shaft seals, the drain
and filler plugs, the actuator and gearbox assembly and the breather tube. Any repairs beyond the items listed
requires a replacement transfer box.
A filler/level plug is provided to ensure that the correct oil level is achieved after a service repair has been carried out.
The level must be checked and adjusted with the transmission fully assembled and the vehicle on level ground. The
transfer box contains 0.996 litres of oil. The transfer box is a fill for life unit and no level check is required at service
unless a leak is present.
TRANSFER BOX
DESCRIPTION AND OPERATION 41-11
Planetary Gearset
The planetary gearset comprises a front and rear carrier half, an input shaft, four planet pinion gears, four planet pinion
shafts and one hundred and forty four needle rollers.
The input shaft is located through the planetary carriers and is driven by the output shaft from the transmission. The
sun gear is located on splines on the input shaft and rotates at the same speed. Rotation of the sun gear is transferred
to the four pinion planet gears which in turn rotate around an annulus gear located in the front casing and secured
with a retaining ring.
The rotation of the planetary pinion gears causes the front and rear carriers to rotate. The rear carrier has gear teeth
which mesh with the teeth in the sleeve. To smooth the transition of the gear teeth of the sleeve and the rear carrier,
an inner and outer blocker ring and a cone are fitted. When the fork moves the sleeve, the three detents in the hub
are pushed, which in turn push the inner and outer blocker rings and the cone together. These items mesh together
at an angle and operate as a synchromesh to provide smooth engagement of the gear teeth and the transition into
low range.
The input shaft also has an outer blocker ring and a cone between the shaft and the hub. When the fork moves the
sleeve, the three detents in the hub are pushed, which in turn push the outer blocker ring and the cone together. These
items also mesh together at an angle and operate as a synchromesh to provide smooth engagement of the gear teeth
of the hub and the input shaft and the transition into high range.
Fork and Rail Assembly
The fork and rail assembly is the main component for changing from high to low ratio and is driven by the actuator
assembly and the lead screw. The actuator rotates the lead screw, via the gearbox, which in turn moves the fork and
rail assembly linearly in plain bearings in the front and rear casings. The fork is positively located in a stepped ring on
the outer diameter of the synchroniser sleeve. Therefore, linear movement of the fork is transferred to the sleeve
which initiates the range change.
TRANSFER BOX
41-12 DESCRIPTION AND OPERATION
Motor and Gearbox Assembly
TRANSFER BOX
DESCRIPTION AND OPERATION 41-13
1 Screw (2 off)
2 Housing
3 Shims
4 Armature and brush assembly
5 Thrust washer
6 Planet gears
7 Sun gear and carrier plate
8 Planet gears
9 Annulus housing
10 Bevel drive gear
11 Housing
12 Electrical connector
13 Thrust washer
14 Drive shaft and bevel gear assembly
15 Mounting plate
16 Screw (3 off)
17 Potentiometer
18 Circlip
19 Gasket (2 off)
20 Cover
21 Screw (6 off)
TRANSFER BOX
41-14 DESCRIPTION AND OPERATION
The actuator and gearbox is located on the rear casing and secured with three bolts. The purpose of the actuator and
gearbox is to electrically change the ratio of the transfer box from low to high and visa versa.
The actuator is a DC four brush motor which is controlled by PWM signals from the transfer box ECU. The wires from
the ECU are large diameter and are twisted to minimise electrical interference. The motor has an internal four pin
integral connector which, when installed in the housing, mates with a female connector located in the housing. The
motor housing contains the magnets which, along with the armature and brush assembly, operate the motor. The
housing is located on the armature and brush assembly mounting plate which in turn is secured with screws into the
main housing. The shaft of the armature and brush assembly locates in a pressed plain bearing in the housing and is
adjusted for end float with shims. The opposite end of the shaft has a toothed gear which mates with the reduction
gearbox.
The reduction gearbox comprises an annulus housing, eight planetary gears and a sun gear and carrier plate. The
annulus housing has a shaft and a planet gear carrier plate. The planet gear carrier plate is attached to the shaft inside
the annulus housing. A bevel gear is attached to the opposite end of the shaft on the outside of the housing. The planet
gear carrier plate has four pins which provide the attachment and pivot points for four planet gears. The sun gear and
carrier plate is located in the annulus housing with the sun gear locating between the four planetary gears. The carrier
plate has four pins which provide for the location and pivot points for four further planetary gears. The toothed gear
on the armature and brush assembly shaft locates between these four gears and provides the drive input into the
reduction gearbox.
The housing is manufactured from cast aluminium and is machined to accept the reduction gearbox and the drive
shaft and bevel gear assembly. Three bosses with holes provide for the attachment of the housing to the transfer box
rear casing assembly. An cast aluminium cover is sealed to the housing with two 'O' section gaskets and secured with
six screws. The housing has a machined hole which is fitted with a plain brass bush to accept the drive shaft and bevel
gear assembly. An oil seal is fitted behind the bush to provide a seal between the drive shaft and the transfer box rear
casing half.
A hole in a boss on the housing allows for the fitment of the ten pin electrical connector to the ECU. The connector is
secured in the housing with a spring clip and lip seal. A machined slot in the housing provides location for a second
connector with four female pins. This connector mates with a similar male connector which is an integral part of the
armature and brush assembly mounting plate and supplies power feed and ground connections for the motor.
The drive shaft and bevel gear assembly comprises a machined shaft, bevel gear and a mounting plate. The drive
shaft has internal splines at one end. The splines have a missing tooth to act as a keyway which mates with the lead
screw, providing the correct timing for the lead screw to the motor position. The bevel gear is an interference fit and
is pressed onto the drive shaft. The opposite end of the shaft accepts the mounting plate and has a machined groove
to provide a positive drive for the rotary potentiometer.
The mounting plate is located on the shaft and is secured in the housing with three screws and retains the drive shaft
laterally. An external hexagonal boss on the mounting plate mates with a hexagonal moulding on the potentiometer.
This provides a positive location for the potentiometer, preventing the potentiometer housing from rotating and
providing the correct orientation for the potentiometer connector.
A third connector in the housing has three female pins which mate with similar male pins on the potentiometer. These
pins supply a 5V reference supply, an output signal and ground for the potentiometer. The connector is connected to
the pins of the ten pin electrical connector.
If the actuator and gearbox assembly is to be removed, the synchroniser sleeve position must be set to high range
using TestBook/T4 before the assembly is removed.
TRANSFER BOX
DESCRIPTION AND OPERATION 41-15
Torsen® Differential
1 Bolt (3 off)
2 Cover plate
3 Pinion gear (6 off)
4 Thrust washer
5 Friction thrust washer
6 Side gear (front propshaft drive)
7 Side gear (rear propshaft drive)
8 Housing/ring gear
The Torsen® Type B traction differential unit is an integral part of the transfer box and is produced by Zexel Torsen
of Belgium. The unit is a full time torque sensing and biasing system using parallel gearing for increased life and quiet
operation.
During normal driving conditions, the Torsen® unit supplies a nominal 50:50 torque output to the front and rear drive
shafts via the transfer box main shaft and the drive sprocket assembly.
The torque biasing capability consists of the ability to 'bias' the torque from the transmission to the axle and wheels
with the higher grip. This must be achieved without causing wheel slip to the wheels of the axle with the lower grip
within the biasing range of approximately 35/65 to 65/35 front to rear.
The torque biasing capability is instantaneous and operates as a preventative system. The unit does not need wheel
slip and speed differentiation to be activated. The unit senses, via torque saturation within the unit, that one propeller
shaft has the intention to rotate faster than the other one. The unit then biases the torque away from that propeller
shaft and applies it to the other propeller shaft. Conventional systems require the wheel slip to occur first before
initiating the torque biasing action. Because the Torsen® unit reacts before the slip occurs, the driving action is very
smooth which results in enhanced grip for the road wheels.
TRANSFER BOX
41-16 DESCRIPTION AND OPERATION
1 Pinion gear (6 off)
2 Side gear (front propshaft drive)
3 Side gear (rear propshaft drive)
4 Cover plate
5 Housing/ring gear
6 Friction thrust washer
7 Thrust washer
8 Roller bearing
The Torsen® unit comprises a housing, two side gears, six pinion gears, thrust and friction washers and a cover plate.
The housing is a machined casting which contains all the differential components. Six machined pockets accept the
pinion gears. The base of each pocket has a cast recess which retains oil to lubricate the pinion gear ends. The closed
end of the housing has a roller bearing pressed into a hole. The transfer box main shaft is located through the bearing
which provides support between the housing and the shaft. The main shaft has cross drillings which supply lubricating
oil from the oil pump to the internal components of the differential.
Three threaded holes are located equally around the open end of the housing and provide for the attachment of the
cover plate with bolts. The outer circumference of the housing has cast and machined teeth which mesh with
corresponding teeth in the transfer box synchroniser sleeve. Rotational input from the transmission is passed, via the
transfer box input shaft, directly to the synchroniser sleeve for high range or indirectly to the synchroniser sleeve via
the planetary gear set for low range. The teeth on the housing allow for the sliding motion of the synchroniser sleeve
when the transfer box range is changed.
The pinion gears are parallel, helical gears which locate in the machined pockets in the housing. The lands of the
helical teeth are ground with a radius which matches the internal diameter of the housing pockets. This creates
frictional forces between the pinion gears and the housing and contributes to the operation of the unit. Each pinion
gear has a machined section with no teeth. The pinions are fitted in the housing in opposite pairs. When fitted, one
pinion gear of each pair meshes with one of the side gears, with the machined section of that gear preventing meshing
with the other side gear.
5
M41 7840
1
4
3
2
7
6
8
TRANSFER BOX
DESCRIPTION AND OPERATION 41-17
The side gears have helical teeth machined on their outer circumference. The inner diameter of the side gears are
different sizes and both have machined splines. The side gear with the smaller diameter bore locates on mating
splines on the main shaft and provides output drive to the rear propeller shaft. The remaining side gear locates on
mating splines on the drive sprocket and, via the chain and the front output shaft, provides output drive to the front
propeller shaft. The side gears are located in the housing, supported laterally by the pinion gears. Transverse location
is provided by the main shaft and three pairs of friction washers.
The friction washers comprise one washer with two ground faces. The second washer has one ground face and the
opposite face has a sintered friction material. Axial thrust applied to the side gears from the pinion gears, forces the
side gears into contact with two of the three pairs of thrust washers, causing a locking of the side and pinion gears
under certain circumstances.
The cover plate is located on the open end of the housing and is secured with three bolts. The cover plate provides
location for the ends of the pinion gears. A cast recess for each pinion gear retains oil to lubricate the pinion gear ends.
Transfer Box ECU
The transfer box ECU is located behind the battery, on the bulkhead. The position of the ECU changes with LH and
RH drive vehicles.
The transfer box ECU is the main unit for controlling the operation of the transfer box. The ECU software was designed
in conjunction with Land Rover, Siemens and New Venture Gear. The ECU is connected on the CAN bus and controls
the transfer box operation using CAN messages from other ECU's on the network.
The transfer box ECU uses three connectors for all inputs and outputs. The ECU receives one permanent power
supply via a 50A fusible link located on the bulkhead, behind the battery, and an ignition supply via fuse 33 in the
passenger compartment fusebox. A second feed via the ignition switch position I and fuse 37 in the passenger
compartment fusebox, activates the neutral selection function. Refer to Operation - Neutral Selection for further
details.
The ECU memorises the position of the actuator when the ignition is switched off. When the ignition is subsequently
switched on, the ECU powers the actuator until the lead screw drives the fork and rail assembly against the end stop
for the previous range. The ECU then calibrates itself to this position and confirms that the selected range is correct.
The ECU controls the closed loop position sensing system within the actuator and regulates the power supply to the
motor to ensure the optimum shift quality is achieved. Using a series of specific software algorithms, the ECU is
capable of adjusting the performance of the synchroniser system to produce smooth and effortless shifting, regardless
of temperature and vehicle speed, providing the neutral and speed parameters are achieved.
The ECU uses a series of programmed shift maps to control the synchronisation speed and ensure that a maximum
shift time of 1.2 seconds is achieved.
If the ECU is replaced, TestBook/T4 must be connected to the vehicle and the transfer box ECU self-calibration
procedure must be performed. This procedure must also be performed if the actuator and gearbox assembly is
replaced.
TRANSFER BOX
41-18 DESCRIPTION AND OPERATION
Default/Limp Home Strategy
If a fault occurs with the transfer box, the transfer box ECU or one of the required input signals, i.e.; road speed signal,
the ECU records an error code and the transfer box low range 'mountain' symbol in the instrument pack flashes
permanently.
As a default setting, the ECU will attempt to engage high or low range in order to allow the vehicle to be driven to a
Land Rover dealer for repair. To ensure a range is engaged, the ignition must be switched off and then on again (timed
shift performs this without ignition cycling). This causes the ECU to power the actuator and engage the previously
selected range.
Transfer Box Harness Connector C1319 Pin Details
Transfer Box Harness Connector C1854 Pin Details
Transfer Box Harness Connector C1855 Pin Details
Pin No. Description Input/Output
1 to 6 Not used –
7 Auxiliary power supply Input
8 HDC switch Input
9 to 12 Not used –
13 CAN bus low Input/Output
14 Not used –
15 Ignition power supply Input
16 Not used –
17 Range change request 1 Input
18 Range change request 2 Input
19 Diagnostic ISO 9141 K line bus Input/Output
20 to 25 Not used –
26 CAN bus high Input/Output
27 to 52 Not used –
Pin No. Description Input/Output
1 to 5 Not used –
6 Actuator potentiometer 5 volt reference voltage Output
7 to 9 Not used –
10 Actuator potentiometer signal Input
11 to 16 Not used –
17 Actuator potentiometer ground –
18 to 40 Not used –
Pin No. Description Input/Output
1 Not used –
2 Ground –
3 Ground –
4 Motor A supply/ground Input/Output
5 Permanent battery power supply Input
6 Permanent battery power supply Input
7 Motor A supply/ground Input/Output
8 Motor B supply/ground Input/Output
9 Motor B supply/ground Input/Output
TRANSFER BOX
DESCRIPTION AND OPERATION 41-19
Diagnostics
The transfer box ECU can store fault codes which can be retrieved using TestBook/T4 or a diagnostic tool using
KW2000* protocol.
Diagnostic Socket
LHD model shown
1 Cover 2 Diagnostic socket
The information is communicated via a diagnostic socket which is located in the fascia, in the driver's side stowage
tray. The socket is secured in the fascia panel and protected by a hinged cover.
The diagnostic socket allows the exchange of information between the various ECU's on the bus systems and
TestBook/T4 or another suitable diagnostic tool. The information is communicated to the socket via a diagnostic DS2
bus. This allows the retrieval of diagnostic information and programming of certain functions using TestBook/T4 or
another suitable diagnostic tool.
The transfer box ECU uses Diagnostic Trouble Codes (DTC) which relate to transfer box electrical faults.
Controller Area Network (CAN) Bus
The CAN bus is a high speed broadcast network connected between various vehicle ECUs.
+ COMMUNICATION DATA BUSES, DESCRIPTION AND OPERATION, Description.
The CAN allows the fast exchange of data between ECU's every few microseconds. The bus comprises two wires
which are identified as CAN high (H) and CAN low (L). The two wires are coloured yellow/black (H) and yellow/brown
(L) and are twisted together to minimise electromagnetic interference (noise) produced by the CAN messages.
In the event of a CAN bus failure the following symptoms may be observed:
l Shift from high to low or low to high inoperative
l Instrument pack low range warning lamp inoperative
l Instrument pack transfer box messages in message centre inoperative.
TRANSFER BOX
41-20 DESCRIPTION AND OPERATION
Operation
General
The selection of high/low range is selected by the driver using a switch adjacent to the transmission selector lever. A
range change can only be performed when the transmission selector lever is in neutral, position 'N'. The accelerator
pedal must not be depressed when a range change is in progress.
If high or low range is requested and the transmission selector lever is a position other than 'N' or 'P', the instrument
pack message centre will display 'SELECT NEUTRAL'.
NOTE: With the transmission selector lever in 'P', the range change will not take place and the 'SELECT NEUTRAL'
message will not be displayed.
When low range is selected, the low range 'mountain' symbol will flash when the range change is taking place and
then remain illuminated when the range change is complete. The instrument pack message centre will display 'LOW
RANGE' for approximately 3 seconds followed by a chime from the instrument pack to confirm that the range change
has been completed. Only 'D' and 'Manual mode' are available on the transmission, the 'Sport mode' selection is not
available.
When high range is selected, the low range 'mountain' symbol will flash when the range change is taking place and
then extinguish when the range change is complete. The instrument pack message centre will display 'HIGH RANGE'
for approximately 3 seconds followed by a chime from the instrument pack to confirm that the range change has been
completed.
The design of the transfer box allows range changes when the vehicle is moving, within set limitations as follows:
l High to Low – at speeds not exceeding 10 mph (16 km/h)
l Low to High – at speeds not exceeding 30 mph (48 km/h).
If the vehicle speed is higher than the parameters given above, the instrument pack message centre will display
'SLOW DOWN'. When the correct speed range is reached, the message will be deleted and the range change will
commence.
A road speed of less than 2 mph (3 km/h) is interpreted by the transfer box ECU as a static shift (vehicle not moving).
In this instance the driver must use the shift lock procedure of operating the brake pedal to allow the selector lever to
be moved from 'N' to 'D' after the range change has been performed.
High range should be used for all normal road driving and also for off-road driving across dry, level terrain. Low range
should only be required where low speed manoeuvring is necessary, such as reversing a trailer, negotiating steep
slippery surfaces or boulder strewn terrain. Low range should also be used for extreme off-road conditions where
progress in high range cannot be maintained. Low range should never be used for normal road driving.
Neutral Selection
The transfer box can be moved into a neutral position for towing the vehicle. The vehicle must not be towed with the
transfer box in high or low range. The transmission must also be in the neutral position. If neutral cannot be selected
on the transmission, the vehicle must not be towed.
TRANSFER BOX
DESCRIPTION AND OPERATION 41-21
1 Spare 5A fuse 2 Fuse 37
To engage the transfer box in neutral, switch the ignition to position II and select neutral 'N' on the transmission
selector lever. Insert a spare 5 Ampere fuse or greater into the empty fuse position 37 in the passenger compartment
fusebox, which is located at the back of the glovebox. Fuse position 37 can be identified using the legend on the
fusebox cover.
Once the fuse is installed, the actuator will engage the transfer box in the neutral position.
Once in neutral, the low range 'mountain' symbol in the instrument pack flashes permanently and 'TRANSFERBOX
NEUTRAL' is displayed in the instrument pack message centre.
Cold Climate Operation
In low ambient temperatures, there may be an increased time delay for the transmission to select neutral. To prevent
the transfer box changing range before the transmission has selected neutral, the transfer box ECU contains software
to delay the range change.
The transfer box ECU receives a transmission fluid temperature message on the CAN. If this temperature is 5°C
(41°F) or below, the transfer box ECU initiates a nominal delay in the range change to allow the transmission to
engage neutral. The delay period is dependant on transmission fluid temperature.
High Range Operation
In high range, the torque input from the transmission is passed to the transfer box input shaft. The position of the
synchroniser sleeve couples the shaft directly to the differential housing. The differential splits the torque between the
two side gears. One side gear is connected by splines and passes the torque to the rear output flange. The second
side gear is connected to the chain drive sprocket and passes the torque, via the chain, to the front output flange.
Low Range Operation
In low range, the torque input from the transmission is passed to the transfer box input shaft. The synchroniser sleeve
is moved and connects the planetary carrier to the differential housing. The torque from the transmission is now
directed through the sun gear of the epicyclic gearset and, via the pinion gears and pinion gear shafts, into the
planetary carrier. The annulus gear of the epicyclic gearset is secured inside the casing and generates the low range
ratio of 2.69:1. The torque is then passed, via the synchroniser sleeve, to the differential housing where it is split
between the two side gears. One side gear is connected by splines and passes the torque to the rear output flange.
The second side gear is connected to the chain drive sprocket and passes the torque, via the chain, to the front output
flange.
TRANSFER BOX
41-22 DESCRIPTION AND OPERATION
Torsen® Differential Operation
The input torque from the transmission is passed via the synchroniser sleeve to the differential housing. The torque
is then transmitted from the housing, through the three pairs of pinion gears and into the differential side gears.
The side gears have opposite handed helical gear forms and intermesh with only one of the pinion gears in each pair.
The pinion gears intermesh with each other as well as individually meshing with only one of the side gears. Between
each pinion gear and the differential housing and on either side of each side gear are friction surfaces or pairs of thrust
washers and friction thrust washers. The pairs of thrust washers control the torque biasing function of the differential.
During normal driving, the differential housing rotates at the same speed as that of the input shaft in high range or the
planetary carrier in low range. If there is no differential motion between the front and rear propeller shafts, then the
differential gear and therefore the side gears will have no relative motion and the whole unit functions as a normal
differential.
If the front or rear wheels suddenly loose traction, a large differential motion between the front and rear propeller
shafts occurs as the slipping wheels begin to accelerate or spin. In this case with a normal differential, the torque
applied to the non-slipping wheels is lost through the differential. With the Torsen® differential, as soon as one wheel
begins to slip, the front and rear output side gears are encouraged to rotate at different speeds. With the side gears
in constant mesh with their relative pinion gears, and the pinion gears meshing with each other, the differential begins
to generate axial and radial thrust loads.
The thrust loads are generated as a result of the helical gear form of the pinion and side gears and they are exerted
onto the thrust washers and friction thrust washers within the differential housing. The friction thrust washers generate
a resistance to the relative motion and produce a locking effect within the differential. This ensures that the torque is
always directed, or biased, towards the propeller shaft with the highest traction and ensures that the vehicle maintains
continuous motion on slippery or uneven surfaces. This action takes place progressively and the driver will be
unaware of its operation.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-1
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AUTOMATIC TRANSM ISSION – GM 5L40-EDESCRIPTION AND OPERATION
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-2 DESCRIPTION AND OPERATION
GM 5L40-E Automatic Transmission
Component Location
RHD model shown
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-3
1 Electronic Automatic Transmission (EAT) ECU
2 Engine Control Module (ECM)
3 Instrument pack
4 Selector lever assembly
5 Gearbox
6 Gearbox valve block and solenoids
7 Gearbox fluid cooler
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-4 DESCRIPTION AND OPERATION
GM 5L40-E Automatic Transmission –
Exploded View
Note the transmission shown is exploded to the extent of the serviceable items
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-5
1 Seal
2 Selector shaft
3 Washer
4 Gasket
5 Extension
6 Seal - Ring extension
7 Speed sensor
8 Selector inhibitor switch
9 Insert - Valve body to main case
10 Solenoids - On/Off
11 Screw - valve body to main case
12 Fluid filter
13 Gasket
14 Fluid pan
15 Drain plug
16 Screw - Fluid pan to main case
17 Solenoid - PWM Torque converter clutch
18 Solenoid - Pressure regulator
19 Wiring harness
20 Harness connector clip
21 Valve body
22 O-ring seal
23 Seal ring
24 Torque converter assembly
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-6 DESCRIPTION AND OPERATION
GM 5L40-E Automatic Transmission –
Sectional View
22
12
14
15
16
17
18
19
20
21
13
11
10
7
6
5
4
3
2
1
8
9
M44 1752
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-7
1 Drive clutch (C2)
2 Brake clutch (CC2)
3 Brake clutch (LBC)
4 Drive clutch (CI)
5 Drive clutch (COD)
6 Drive clutch (C1)
7 Drive clutch (CR)
8 Brake clutch (CC1)
9 Fluid pan
10 Fluid filter
11 Fluid pump cover plate
12 Bell housing
13 Torque converter
14 Fluid pump
15 Main casing
16 Drive clutch (CD)
17 Freewheel clutch FW1 (forward clutch sprag)
18 Freewheel clutch FW3 (intermediate clutch
sprag)
19 Freewheel clutch FW4 (low clutch sprag)
20 Freewheel clutch FW2 (second clutch sprag)
21 Extension case
22 Output shaft
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-8 DESCRIPTION AND OPERATION
GM 5L40-E Automatic Transmission –
Valve Block and Solenoid Valves
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-9
1 Torque converter clutch PWM solenoid
2 Feed limit valve
3 Torque converter clutch regulator valve
4 Low pressure regulator valve
5 Reverse lockout valve
6 Manual valve
7 4th-5th shift valve
8 4th-5th control valve
9 4th-5th shift solenoid (C)
10 2nd-3rd shift solenoid (B)
11 2nd-3rd control valve
12 1st-2nd shift solenoid (A)
13 2nd-3rd shift valve
14 1st-2nd control valve
15 1st-2nd shift valve
16 Accumulators
17 Default mode valve
18 Pressure control solenoid
19 3rd-4th shift valve
20 3rd-4th control valve
21 Solenoid retaining clip
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-10 DESCRIPTION AND OPERATION
GM 5L40-E Automatic Transmission –
Fluid Pump Cover Plate Assembly
A. Fluid pump line (output) pressure
B. Pressure regulator fluid pump decrease pressure
C. Fluid pump suction (feed) line from fluid pan
1
1
5
13
2
18
15
14
19
1
6
1
5
7
16
17
13
12
11
10
9
7
8
6
21
7
20
M44 1754
A =
B =
C =
1
2
4
3
4
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-11
1 Bleed valves
2 Line pressure (pump output)
3 Reverse clutch
4 Forward clutch
5 Coast clutch
6 Direct clutch
7 Exhaust (return to fluid pan)
8 Pressure relief ball valve
9 Torque converter clutch release pressure
10 Feed to fluid cooler
11 Torque converter clutch apply pressure
12 Torque converter clutch control valve
13 Torque converter clutch enable valve
14 Regulated apply pressure
15 Torque converter clutch signal pressure
16 Fluid pump
17 Fluid pump screen assembly
18 Suction feed from fluid pan
19 Throttle signal (from pressure regulator
solenoid)
20 Boost valve
21 Pressure regulator valve
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-12 DESCRIPTION AND OPERATION
GM 5L40-E Automatic Transmission
Control Diagram
A = Hardwired; D = CAN Bus; J = ISO 9141 K Line
M44 1755
A
J
D
13 12
14
15
16
9
1
2
3
4
5
6
7
8
10
11
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-13
1 Permanent battery supply (30A Fuse)
2 Battery supply (100A Fuse)
3 Main relay
4 Starter relay
5 Transmission fluid temperature sensor
6 Input speed sensor
7 Output speed sensor
8 Brake switch
9 EAT ECU
10 Inhibitor switch
11 Solenoid valves
12 Engine Control Module (ECM)
13 Instrument pack
14 Diagnostic socket
15 Selector lever switches
16 Shift interlock solenoid
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-14 DESCRIPTION AND OPERATION
Description
General
The GM 5L40-E transmission is an electronically controlled, five speed unit specifically for use with the Td6 diesel
engine. The transmission is manufactured by General Motors (GM) Powertrain in Strasbourg, France.
The transmission is controlled by an Electronic Automatic Transmission (EAT) ECU which contains software to
provide operation as a semi-automatic 'Steptronic' transmission. This allows the transmission to be operated as a
conventional automatic unit by selecting P, R, N, D on the selector lever. Movement of the selector lever across the
gate to the 'M/S' position puts the transmission into electronic sport mode. Movement of the selector lever in a lateral
position to the + or – positions puts the transmission into electronic manual 'Steptronic' mode.
The GM 5L40-E transmission has the following features:
l Designed to provide maintenance free operation
l Transmission fluid is 'fill for life'
l The torque converter features a gradual slip lock up feature with electronic control of lock up and smooth
transition to the fully locked condition
l Torque converter lock up is available in 3rd, 4th and 5th gears
l EAT ECU controls shift program logic
l Connected to ECM via the CAN for system communications
l Diagnostics available from the EAT ECU via the ISO 9141 K Line
l Default mode if major faults occur.
The transmission comprises three main castings; the bell housing, the main casing and the extension case. These
items are bolted together to form the housing for the transmission components.
A single piece fluid pan is bolted to the lower face of the main case and secured with screws. The fluid pan is sealed
to the main case by a controlled compression gasket. Removal of the fluid pan allows access to the valve block and
solenoids. The fluid pan is fitted with a magnet which collects any metallic particles present in the fluid.
The fluid pan also houses a fluid filter which is non-serviceable. If the transmission fluid becomes contaminated or
after any procedure requiring the fluid to be drained, the filter must be replaced.
The bell housing provides protection for the torque converter. The torque converter is a complete assembly which also
contains the variable control lockup clutch. The torque converter also drives a vane type fluid pump via two drive
tangs. The fluid pump is located in the bell housing, behind the fluid pump cover. The fluid pump cover and the bell
housing are bolted together. The bell housing and fluid pump cover assembly is bolted to the main casing.
The main casing contains the following components:
l Input shaft
l Output shaft
l Valve block and solenoids
l Six multiplate drive clutches
l Three multiplate brake clutches
l Four free wheel, one way, sprag type clutches
l A planetary gearset assembly.
Draining and refilling the transmission is carried out via a drain plug, located in the sump of the transmission and a
refill/level plug located on the left hand side of the transmission. When checking the transmission fluid level the fluid
must be between 35°C and 45°C. Only Texaco ETL-7045E Automatic transmission fluid should be used for refilling /
topping up the transmission.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-15
Torque Converter
Torque Converter Components
1 Converter housing cover assembly
2 Pressure plate assembly
3 Damper assembly
4 Turbine
5 Stator
6 Impeller
The torque converter is located in the bell housing on the engine side of the transmission. The torque converter is the
coupling element between the engine and the transmission. The driven power from the engine crankshaft is
transmitted hydraulically and mechanically according to the gear selected and the operating conditions, through the
torque converter to the transmission. The torque converter is connected to the engine by a drive plate.
The torque converter comprises an impeller, a stator and a turbine. The torque converter is an enclosed unit between
the converter housing cover assembly and the impeller assembly. The two components are welded together to
provide a sealed housing with all torque converter components located in a fluid filled housing.
The converter housing cover assembly has three threaded bosses which provide for attachment to a drive plate which
in turn is connected to the engine crankshaft. The threaded bosses also provide for location of special tools to allow
the torque converter to be removed from the bell housing. With the impeller assembly welded to the converter housing
cover assembly, the impeller speed is therefore governed by engine speed.
Impeller
The impeller is mechanically connected to the engine and rotates at engine speed. The impeller outer body has a
boss with two machined slots. The boss is located over the transmission input shaft and the slots locate in two tangs
on the fluid pump to provide the fluid pump drive.
The impeller comprises a continuous row of blades attached to the outer body. The root of the blades collect fluid
which flows by centrifugal force around the curved outer surface of the impeller to the tip of the blades.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-16 DESCRIPTION AND OPERATION
Fluid Flow
1 Turbine
2 Stator
3 Impeller
When the engine is running, the rotating impeller acts as a centrifugal pump, picking up fluid at its centre and
discharging fluid at high velocity through the blades on its outer rim. The design and shape of the outer row of blades
and the impeller outer body cause the fluid to rotate in a clockwise direction as it leaves the impeller. This improves
the efficiency of the fluid as it contacts the outer row of blades on the turbine.
The centrifugal force of the fluid exiting the impeller outer blades is passed to the curved inner surface of the turbine
via the outer row of blades. The velocity and clockwise rotation of the fluid causes the turbine to rotate.
Turbine
The turbine is similar in design to the impeller with a continuous row of blades. The fluid entering the tip of the blades
is directed around the curved body of the turbine to the root of the blades. The curved surface of the turbine redirects
the fluid back in the opposite direction to which it entered the turbine, increasing the turning force applied to the turbine
from the impeller. This is known as torque multiplication.
When the engine is idling, the impeller is rotating at a slow speed. The force of the fluid exiting the impeller does not
have sufficient force to turn the turbine at high speed. In this condition the vehicle can be in gear without any forward
or reverse motion being generated.
When the engine speed increases, the turbine speed also increases. The fluid leaving the inner row of the turbine
blades is rotated in an anti-clockwise direction due to the curve of the turbine and the shape of the blades. The fluid
is now flowing in the opposite direction to the engine rotation and therefore the impeller. If the fluid was allowed to hit
the impeller in this condition, it would have the effect of applying a brake to the impeller, eliminating the torque
multiplication effect. To prevent this, the stator is located between the impeller and the turbine.
Stator
The stator is mounted on the transmission shaft on a roller clutch. The stator comprises a number of blades which are
aligned in an opposite direction to those of the impeller and the turbine. The main function of the stator is to redirect
the fluid returning from the turbine, changing its direction of rotation to that of the impeller.
The redirected fluid from the stator is directed at the inner row of blades of the impeller, assisting the engine in turning
the impeller. This sequence increases the force of the fluid emitted from the impeller and thereby increasing the torque
multiplication effect of the torque converter.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-17
Stator Functions
1 Blades
2 Stator held - fluid flow re-directed
3 Stator rotates freely
4 Roller clutch
5 Converter at coupling speed
6 Fluid flow from turbine
7 Converter multiplying
8 Fluid flow from impeller
9 Drive from engine
10 Impeller
11 Stator
12 Turbine
13 Output to transmission
Refer to the 'Stator Functions' illustration
Fluid emitted from the impeller acts on the turbine. If the turbine is rotating at a slower speed than the fluid from the
impeller, the fluid will be deflected by the turbine blades in the path 'A'. The fluid is directed at and deflected by the
stator blades from path 'B' to path 'C'. This ensures that the fluid is directed back to the pump in the optimum direction.
In this condition the roller clutch is engaged and the force of the fluid on the stator blades assists the engine in rotating
the impeller
As the rotational speed of the engine and therefore the turbine increases, the direction of the fluid leaving the turbine
changes to path 'D'. The fluid is now directed from the turbine to the opposite side of the stator blades, rotating the
stator in the opposite direction. To prevent the stator from resisting the smooth flow of the fluid from the turbine, the
roller clutch releases, allowing the stator to rotate freely on it shaft.
When the stator becomes inactive, the torque converter no longer multiples the engine torque. When the torque
converter reaches this operational condition it ceases to multiply the engine torque and acts solely as a fluid coupling,
with the impeller and the turbine rotating at approximately the same speed.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-18 DESCRIPTION AND OPERATION
Uni-directional Roller Clutch
A. Unlock; B. Lock
1 Roller
2 Cage
3 Spring
4 Inner race
5 Stator
The roller clutch used on the stator uses ten parallel rollers, located between the smooth, cylindrical inner race and
the inclined cam faces of the stator body. Springs are used to hold the rollers in position between the two contact
faces.
When the stator is rotated in a clockwise direction, the rollers become trapped between the inner race and the inclined
cam faces of the stator body, providing positive (locked) rotation of the inner race. When the stator is rotated in an
anti-clockwise direction, the rollers are moved away from the inclined cam faces and can rotate freely (unlocked) with
the stator body, providing no drive from the stator to the inner race. In this condition the stator can rotate freely on the
inner race.
Lock-up Clutch Mechanism
The Torque Converter Clutch (TCC) is hydraulically controlled by a solenoid which in turn is controlled by PWM
signals from the EAT ECU. This allows the torque converter to have three states of operation as follows:
l Fully engaged
l Controlled slip variable engagement
l Fully disengaged.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-19
Lock-up Clutch Mechanism Circuit
1 Torque converter
2 Fluid cooler return
3 TCC Apply pressure
4 TCC release pressure
5 Fluid cooler feed
6 TCC control valve
7 TCC regulated apply pressure
8 TCC signal pressure
9 TCC enable valve
10 Regulated apply pressure
11 TCC regulator valve
12 TCC solenoid valve
13 Pressure input from feed limit valve
14 Line pressure input from fluid pump
15 Torque converter pressure (from pressure
regulator valve)
16 Fluid cooler
17 Converter feed limit circuit
11
12
16
1
M44 1759
2
3
4
5
7
10
15
14
13
17
6
8
9
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-20 DESCRIPTION AND OPERATION
The Torque Converter Clutch (TCC) is controlled by a solenoid valve located in the valve block. The solenoid valve
is activated by PWM signals from the EAT ECU to provide no lock-up, partial lock-up or full lock-up of the TCC.
The solenoid valve provides signal pressure to a TCC enable valve and a TCC control valve which are located in the
fluid pump cover assembly. These two valves together control the operation of the TCC and also the fluid flow to the
fluid cooler.
TCC Control Valve – The TCC control valve is controlled by signal pressure from the TCC solenoid valve. The TCC
control valve directs torque converter pressure to the release side of the TCC and into the fluid cooler circuit. The
control valve also directs regulated apply pressure to the TCC.
The control valve is held in the release position by spring force when the TCC solenoid valve is de-energised. When
the EAT ECU energises the TCC solenoid, signal pressure from the regulator valve moves the control valve against
the spring force into the apply position. This allows regulated pressure to be applied to the TCC apply circuit.
TCC Enable Valve – When the TCC is in the released condition, torque converter pressure is directed through the
valve and into the converter feed limit circuit to the control valve. If the TCC control valve becomes defective and stays
at the TCC apply position when the TCC solenoid is de-energised, the converter feed limit pressure enters the release
side of the TCC and prevents TCC overheating.
When the TCC solenoid is energised, signal pressure from the regulator valve moves the enable valve against the
spring force and allows regulated pressure to be directed to the TCC control valve and into the TCC apply circuit.
Fluid Pump
The fluid pump is an integral part of the transmission. The fluid pump is used to supply hydraulic pressure for control
valve and clutch operation and also to pass the fluid through the transmission fluid cooler.
The 5L40-E fluid pump is a vane type pump which is driven from a direct coupling with the torque converter impeller.
The fluid pump rotational speed is therefore governed by the engine speed.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-21
Fluid Pump
1 Line (output) pressure
2 Decrease pressure (input)
3 Bell housing
4 Slide
5 Spring
6 Fluid supply from fluid pan
7 Drive tangs
8 Rotor
9 Vane
The pump comprises a rotor with thirteen vanes which are located in a recess in the rear face of the bell housing. A
pump cover, with cast channels to direct fluid flow, is bolted to the bell housing to enclose the pressure regulator, the
boost valve, the TCC enable valve, the TCC control valve and the springs.
The rotor and vanes are located in a slide. As the rotor is turned, centrifugal force causes the vanes to move outwards
in the slots in the rotor and contact the inner surface of the slide. As the rotor is turns, the vanes collect fluid from the
oil supply port in the pump cover. The vanes carry the fluid to the line output pressure port in the pump cover where
it passes into the transmission valve block.
The slide is mounted on a pivot pin and can move about the pin axis controlled by a calibrated spring and line pressure
from a pressure regulator valve in the valve block.
As the slide pivots, it changes the eccentricity of the rotor to the slide. This changes the swept volume of the vanes
and hence the pump output volume.
As the rotor turns and the vanes pass the line pressure port, the space between the rotor vanes and the slide
increases. The increasing volume between the vanes causes a depression which draws fluid (which is subject to
atmospheric pressure) from the fluid pan as the vanes pass the fluid supply port.
As the rotor turns and the vanes pass the fluid supply port, the fluid becomes trapped between the vanes. As the rotor
turns further, the space between the vanes decreases, pressurising the fluid. When the vanes reach the line pressure
port, the fluid is displaced under pressure into the port to provide the operational pressure for the transmission.
M44 1761
8
9
6 5
4
3
1
2
8
7
9
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-22 DESCRIPTION AND OPERATION
Fluid Pump Output (Slide) Adjustment
1 Pivot pin
2 Decrease flow
3 Decrease pressure
4 Calibrated spring pressure
5 Increase flow
When the engine is cranked, there is no pressure in the system, and the calibrated spring holds the slide at a position
to provide the pump with the maximum swept volume. This provides a fast prime of the pump and immediate
lubrication and hydraulic pressure for the transmission.
During normal driving conditions, maximum output is not required. The pressure regulator valve applies a decrease
pressure to the slide against the calibrated spring pressure to maintain the optimum output to meet the operating
conditions. Minimum pump output is obtained when the spring is fully compressed by the decrease pressure.
M44 1762
1
2
5
3
4
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-23
Valve Block and Solenoid Valves
1 Torque converter clutch PWM solenoid
2 Feed limit valve
3 Torque converter clutch regulator valve
4 Low pressure regulator valve
5 Reverse lockout valve
6 Manual valve
7 4th-5th shift valve
8 4th-5th control valve
9 4th-5th shift solenoid (C)
10 2nd-3rd shift solenoid (B)
11 2nd-3rd control valve
12 1st-2nd shift solenoid (A)
13 2nd-3rd shift valve
14 1st-2nd control valve
15 1st-2nd shift valve/clutch accumulator
16 1st-2nd shift valve
17 2nd-3rd shift valve/clutch accumulator
18 4th-5th shift valve/clutch accumulator
19 Default mode valve
20 3rd-4th shift valve/clutch accumulator
21 Pressure control solenoid
22 3rd-4th shift valve
23 3rd-4th control valve.
The valve block is located in the bottom of the transmission and is covered by the fluid pan. The valve block provides
electro-hydraulic control for all transmission functions and comprises the following components:
l Valve block body
l Pressure regulator solenoid
l Torque converter clutch solenoid
l Three shift solenoids
l Thirteen hydraulic spool valves
l Four accumulators
l Manual valve.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-24 DESCRIPTION AND OPERATION
Pressure Regulator Solenoid
1 Coil winding
2 Valve
3 Pressure supply
4 Regulated control pressure
5 Return
6 Spring.
The pressure regulator solenoid is located in the valve block and is secured with a spring clip. The solenoid operates
in conjunction with the pressure regulator valve to control line pressure supplied to the clutches and shift control
valves. The solenoid is controlled by PWM signals from the EAT ECU in response to throttle position and engine
torque signals from the ECM.
When the solenoid is de-energised the pressure controlled by the solenoid is at maximum. In this condition the valve
is moved under the influence of the spring, closing the return port and allowing supply pressure to pass to the clutches
and control valves. As the EAT ECU increases the PWM output to the solenoid coil winding, the valve is lifted, against
the spring force, opening the return port to the supply pressure. The supply pressure is directed into the return port
proportional to the controlled opening of the valve. By varying the PWM signal to the coil winding and consequentially
adjusting the valve opening, the pressure regulator solenoid controls the supply pressure and the regulated pressure
supplied to the clutches and valves. The pressure regulator solenoid receives the supply pressure from the feed limit
valve.
The resistance of the solenoid coil winding is between 3.5 and 4.6 Ω at 20°C (68°F).
Pressure Regulator Valve
The pressure regulator valve is located in the fluid pump cover. Output from the fluid pump is directed to the pressure
regulator valve via the regulator solenoid valve, to control the output pressure before distribution to the transmission.
When the pump is operating at maximum output, i.e.; at initial engine start-up, line pressure from the fluid pump is felt
at the accumulators, the spool valves, the pressure regulator valve and the manual valve. The pressure moves the
regulator valve against its spring and line pressure is directed into the feed line to the torque converter clutch control
valve, which is located in the fluid pump body, and the decrease pressure feed line to the fluid pump slide.
M44 1765
6 5 4
1 2
3
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-25
1 Fluid pump decrease pressure
2 Fluid pump line (output) pressure
3 Torque converter clutch control valve feed
pressure
4 Pressure regulator valve
5 Boost valve
6 Boost valve sleeve
7 Throttle signal from pressure regulator solenoid
8 Reverse clutch pressure
9 Air bleed valve.
The pressure in the decrease fluid pressure line acts on the slide, reducing the fluid pump output and the pressure in
the feed line. The reduced line pressure is subsequently felt at the pressure regulator valve and consequently exerts
less fluid pressure in the decrease pressure line. This causes the slide to move under the calibrated spring pressure
and increase the pump output. In this way the fluid pressure is constantly regulated.
The fluid pressure required to operate the clutches is controlled by the pressure regulator solenoid located in the valve
block. The EAT ECU controls the position of the solenoid in relation to throttle position and engine torque signals from
the ECM. As the solenoid is operated, a throttle signal pressure is applied which moves the boost valve and varies
the spring pressure on the regulator valve.
M44 1764
1
2
3
9
7
8
4
5
6
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-26 DESCRIPTION AND OPERATION
Torque Converter Clutch (TCC) Solenoid
1 Housing
2 Armature
3 Diaphragm
4 Exhaust
5 Exhaust seat
6 O-ring (internal)
7 O-ring
8 TCC signal fluid
9 Reverse fluid
10 Metering ball
11 Inlet seat
12 Coil assembly
13 Stainless steel shim
14 Connector
The torque converter clutch solenoid is located in the valve block and secured with a spring clip. The TCC solenoid
valve is a normally closed, pulse width modulated (PWM) solenoid used to control the apply and release of the torque
converter clutch. The EAT ECU operates the solenoid with a negative duty cycle, at a fixed frequency of 32 Hz, to
control the rate of clutch apply and release. The solenoid's ability to apply and release the TCC in a linear fashion
results in smoother TCC operation.
When TCC application is required, the EAT ECU increases the duty cycle to allow the TCC PWM solenoid valve to
control TCC signal pressure at a level sufficient to move the TCC enable valve and control valve to the apply position.
Release pressure is directed to return and regulated apply pressure is directed to the apply side of the converter
pressure plate/damper assembly.
The EAT ECU increases the duty cycle to control a slippage of 20-80 rev/min between the pressure plate/damper
assembly and the converter cover. This reduces engine vibrations passing into the transmission and allows the TCC
to be applied at low engine speeds in 2nd, 3rd, 4th and 5th gears. At high speeds, lock-up mode is activated by
activating the TCC PWM solenoid at maximum duty cycle.
Some operating conditions may prevent or enable TCC application under certain conditions, such as engine
temperature and transmission temperature.
The resistance of the solenoid coil winding is between 10.0 and 11.5 Ω at 20°C (68°F). The resistance should
measure approximately 16 Ω at 150°C (302°F).
M44 1767
1
11
12
13
14
10
23
8
7765
4
9
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-27
Shift Control Solenoids
1 Housing
2 Armature
3 Diaphragm
4 Exhaust
5 Exhaust seat
6 O-ring
7 Fluid screen
8 O-ring
9 Fluid screen
10 Solenoid signal fluid
11 Feed limit fluid
12 Metering ball
13 Plunger
14 Coil assembly
15 Spring
16 Connector
Three identical shift solenoids are used to control the operation of the transmission and select the required gear
ranges. Each solenoid is a three port, on/off, normally closed solenoid controlled by the EAT ECU and are similar in
construction to the torque converter clutch solenoid.
The EAT ECU provides a ground which energises the solenoid. Current flows through the solenoid coil, energising
the coil which, in turn retracts the plunger. The feed limit pressure pushes the metering ball against the exhaust seat,
blocking the exhaust port. The feed limit pressure is now directed through the nose of the solenoid valve and creates
the signal pressure.
The shift control solenoids are de-energised when the EAT ECU removes the ground, breaking the electrical circuit.
When the solenoid is de-energised, the spring force pushes the plunger which in turn, lifts the metering ball off its
exhaust port seat. The metering ball then blocks feed limit pressure from entering the signal pressure port. Any
residual signal pressure remaining flows past the metering ball and exits via the exhaust port.
The resistance of the solenoid coil winding is between 15.0 and 17.0 Ω at 20°C (68°F). The resistance should
measure approximately 24 Ω at 150°C (302°F).
M44 1916
1
10
11
13
14
15
16
12
23
9
8765
4
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-28 DESCRIPTION AND OPERATION
Spool Valves
The valve block contains fourteen spool valves which control various functions of the transmission. The spool valves
are of a conventional design and are either operated by fluid pressure or by solenoid operation.
Typical Spool Valve
1 Spring
2 Ports
3 Solenoid valve
4 Spring
5 Exhaust ports (return to fluid pan)
6 Spool - control valve
7 Spool - shift valve
8 Waisted area
9 Piston
Each spool valve is located in its spool bore and held in a default (unpressurised) position by a spring. The spool bore
has a number of ports which allow fluid flow to other valves and clutches to enable transmission operation. Each spool
comprises one or more pistons which are waisted to allow fluid to be diverted into the applicable ports when the valve
is operated.
When fluid pressure or solenoid actuation moves the spool, a port in the spool bore is uncovered or covered. Fluid
flows or is prevented from flowing into the waisted area and into another uncovered port where it is passed to either
another spool valve, clutch or returned to the fluid pan.
Accumulators
The valve block has four accumulators which are used to improve the shift 'feel' of shift changes. This is achieved by
absorbing the clutch apply pressure for the second, third, fourth and fifth clutches.
M44 1768
1
2
3
4
6
7
8
9
55
5
5
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-29
1 Line pressure from fluid pump
2 Bleed port
3 Clutch apply pressure from shift control valve
4 Damped clutch apply pressure from shift
control valve
5 Spring
6 Piston
The accumulators comprise a piston, a housing and a spring. The piston is sealed in the housing with O-ring seals
and is subject to pressure applied by the spring. The housing has connection ports for fluid pump line pressure which
is applied to the annulus of the piston and a port which receives clutch apply pressure from the shift valve and is
applied to the full area of the piston.
When line pressure from the pump is present, the piston is moved against the spring pressure. When a shift valve
moves to supply clutch apply pressure, this is applied not only to the clutch piston but also to the accumulator piston.
With the clutch apply pressure on the full area of the piston and with assistance from the spring, the piston is moved
back against the line pressure. These opposing pressures create an action similar to a shock absorber.
When the shift valve supplies clutch apply pressure, the pressure initially moves the clutch piston against the clutch
piston spring and clutch plates. When the initial clearance between the plates is taken up, the clutch apply pressure
builds rapidly. The clutch apply pressure is also applied to the full area of the accumulator piston and the rapid build
up of pressure moves the accumulator piston against the line pressure, assisted by the spring.
The movement of the accumulator piston delays the build up of pressure in the circuit and provides for a more gradual
application of the clutch, resulting in a smoother clutch take-up.
When the shift valve moves to cut-off the clutch apply pressure, the line pressure pushes the piston down the housing
against the spring.
5
5
M44 1769
1
2
3
4
6
1
2
6
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-30 DESCRIPTION AND OPERATION
Feed Limit Valve
The shift control solenoids and the pressure regulator solenoid will be damaged if subjected to the line pressure output
from the fluid pump. The feed limit valve reduces the pressure supplied to the solenoids to a pressure within the design
limits of the solenoids.
The feed limit valve is spring loaded spool valve which moves under line pressure to relieve some fluid to the return
line and the fluid pan, allowing fluid at reduced pressure to feed the solenoids.
Reverse Lock-out Valve
The reverse lock-out valve prevents reverse gear from being engaged until the vehicle speed is below 5 mph (8 km/
h) in high range or below 2 mph (3 km/h) in low range.
When the vehicle is travelling above the defined speeds, the EAT ECU maintains the pressure regulator valve
solenoid in the energised condition. This allows the torque converter signal pressure from the solenoid to hold the
reverse lock-out valve spool. The spool is held in a position which prevents the reverse signal pressure from the
manual valve activating the clutches required for reverse selection.
Drive Clutches
Multiplate Drive or Brake Clutch – Typical
1 Clutch housing
2 Apply piston
3 Friction plate
4 Hub
5 Steel drive plate
6 Piston release springs
7 Input shaft
8 Clutch apply pressure
M44 1770
6
7
8
1
3
2
4
5
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-31
Nine clutch mechanisms are used in the 5L40-E transmission unit. There are six drive clutches and three brake
clutches which comprise of one or more friction plates depending on the output they control. A typical clutch will
consist of a number of steel outer plates and inner plates with friction material bonded to each face.
When the clutch is operated, the torque transmitted through the plates is dependant on the friction of the plates and
the pressure applied to them. If one of these two factors is inadequate then clutch slippage will occur.
Depending on the application, the outer and inner plates will be splined to the hub or housing. This allows the drive
from the hub for instance to be connected or braked by the housing when the clutch is applied.
The clutch is actuated hydraulically by a piston arrangement which applies pressure to drive the outer and inner plates
together. The hydraulic pressure is received from the applicable shift valve and damped by the relevant accumulator
to provide a smooth clutch take-up. Springs are fitted to oppose the piston movement. When the apply pressure is
decayed, the springs move the piston away from the plates and ensure that they are fully disengaged. If the plates
are allowed to 'drag', the friction decreases the efficiency of the transmission and causes premature wear of the friction
plates.
Clutch Released
1 Clutch housing
2 Clutch discs separated
3 Clutch apply pressure port (no pressure)
4 Apply piston
When no clutch apply pressure is applied to the piston, the springs hold the piston away from the plates. This prevents
the plates from meshing together and allows them to rotate freely with no drive transmitted from the hub to the
housing.
Clutch Applied
1 Clutch apply pressurised fluid
2 Apply piston
3 Clutch discs forced together
4 Clutch apply pressure port (Apply pressure
present)
M44 1771
2
3
4
1
M44 1772
4
3
1
2
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-32 DESCRIPTION AND OPERATION
When hydraulic apply pressure from the applicable shift valve is initially applied to the piston, the pressure overcomes
the spring force and moves the piston into contact with the plates. This initial movement takes up any clearance
between the plates. As the pressure behind the piston rapidly increases, the rapid pressure rise is damped by the
appropriate accumulator, allowing the piston to apply force to the plates gradually. This provides a smoother clutch
take up. With the plates meshed together, the housing can now be driven with the hub or the hub can be held
stationary.
One Way Free Wheel Clutch
1 Sprags
2 Inner race
3 Outer race
4 Sprag and cage assembly
5 Sprag outer race
6 Sprag inner race
7 Retaining ring
The 5L40-E transmission uses four free wheel clutches to perform shifting and component holding functions. The free
wheel clutch, in conjunction with the damped application of the hydraulic clutches helps prevent disruption to the
power output during up shifts and downshifts.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-33
The free wheel clutches can perform three functions; hold components stationary, drive components and free wheel
allowing components to rotate without a drive output. The free wheel clutches used in the 5L40-E transmission are of
the sprag type and comprise an inner and outer race and a sprag and cage assembly. The inner and outer races are
pressed into their related components with which they rotate. The sprag and cage assembly is located between the
inner and outer races.
The sprags are located in a cage which is a spring which holds the sprags in the 'wedge' direction and maintains them
in contact with the inner and outer races.
Referring to the illustration, the sprags are designed so that the dimension 'B' is larger than the distance between the
inner and outer race bearing surfaces. When the outer race rotates in a clockwise direction, the sprags twist and the
edges across the dimension 'B' wedge between the races, providing a positive drive through each sprag to the inner
race. The dimension 'A' is smaller than the distance between the inner and outer race bearing surfaces. When the
outer race rotates in an anti-clockwise direction, the dimension 'A' is too small to allow the sprags to wedge between
the races, allowing the outer race to rotate freely.
On the illustration shown, when the outer race is rotated in a clockwise direction, the sprags twist and are 'wedged'
between the inner and outer races. The sprags then transfer the rotation of the outer race to the inner race, which
rotates at the same speed.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-34 DESCRIPTION AND OPERATION
Planetary Gearset
1 Input sun - front
2 Planetary pinion - long
3 Input sun - rear
4 Rear planetary pinion - short
5 Output shaft gear
6 Ring gear - front
7 Front planetary pinion - short
8 Planetary carrier
The planetary gearset used in the 5L40-E transmission comprises of a front and rear section which together form a
compound gear train. The gearset operates in conjunction with the clutches, brakes and freewheel clutches to
produce the five forward gears and the reverse gear.
The planetary gearset is a single integral assembly with a common planetary carrier and a common set of long
planetary gears. The gearset assembly comprises:
l Two separate external ring gears
l A common planetary carrier
l Two separate (front and rear) input sun gears
l One set of rear short planetary gears
l One set of front short planetary gears
l One set of three long planetary gears which are common to front and rear sections.
1
5
6
M44 1774
A
B
A
B
4
5
4
6
7
3
2
1
8
2
7
3
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-35
The gearset has three elements; torque inputs, reaction components and torque outputs.
The three possible torque inputs are:
l Planetary carrier
l Front input sun gear
l Rear input sun gear.
The three possible reaction components are:
l Planetary carrier
l Front ring gear
l Front input sun gear.
One torque output:
l Rear ring gear.
The following table shows the different combinations of input components, reaction components and output
components required to achieve the five forward gears and the one reverse gear ratio.
Gear Ratios
Gear Input Reaction Output Ratio
1st Rear input sun gear Planetary carrier Rear ring gear 3.42
2nd Rear input sun gear Front ring gear Rear ring gear 2.21
3rd Rear input sun gear Front input sun gear Rear ring gear 1.600
4th Rear input sun gear and planetary carrier None Rear ring gear 1.00
5th Planetary carrier Front input sun gear Rear ring gear 0.75
Reverse Front input sun gear Planetary carrier Rear ring gear 3.03
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-36 DESCRIPTION AND OPERATION
Power Flows
Operation of the transmission is controlled by the EAT ECU which electrically activates various solenoids to control
the transmission gear selection. The sequence of solenoid activation is based on programmed information in the ECU
memory and physical transmission operating conditions such as vehicle speed, engine load, throttle position and
selector lever position.
Powerflow Schematic Diagram
1 Torque input from engine
2 Torque converter lock-up clutch
3 Torque converter unit
4 Fluid pump
5 One way clutch
6 Transmission case
7 Front input sun gear
8 Planetary carrier
9 Front ring gear
10 Front planetary pinion – short
11 Planetary pinion – long
12 Output shaft ring gear
13 Rear planetary pinion – short
14 Rear input sun gear
15 Torque output from transmission
Engine torque output is transferred, via operation of single or combinations of clutches, to the planetary gearset. The
planetary gearset is controlled by reactionary inputs from brake clutches and freewheel clutches to produce five
progressive forward ratios and a single reverse ratio.
The following tables show which clutches are operating for selected gear ratios and which solenoids are activated to
produce the required torque output from the transmission.
Gear Range Reference Chart
M44 1775
2
3
1
4
5
CC1
C1
CD
CR
FW1
FW3
FW4
FW2
CI
COD LBC
C2
CC2
7
8
6
9
10
11
12
13
14
15
Gear
Selector
Lever
Position
Gear Engine
Braking
Yes/No
Ratio Clutches Freewheels
C1 C2 CI CD COD CC1 LBC CC2 CR 1 2 3 4
D 1 Y * 3.42X XX(*) X X
D2 Y2.21XX X X XX
D 3 Y 1.60XXX XX X X
D 4 Y 1.00XXXX X X
D 5 Y 0.75XXXXX
P/N –– –
R Y–3.03 X X
RLO
* = Optional
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-37
Hydraulic Default Mode Reference Chart
Gear Change Solenoid Reference Chart
Hydraulic Default Mode Solenoid Reference Chart
NOTE: When default mode occurs when driving (no EAT ECU signal to the shift solenoid valve), the transmission will
shift to 5th gear.
If the engine is then switched off and then on, 4th gear will then be selected (for better take off from standstill). The
transmission will then remain in 4th gear.
Gear
Selector
Lever
Position
Gear Engine
Braking
Yes/No
Ratio Clutches Freewheels
C1 C2 CI CD COD CC1 LBC CC2 CR 1 2 3 4
D5Y0.75XXXXX
D4Y4XXXX X X
Gear Selector Lever
Position
Gear Solenoids
High Range Low
Range
ABCTCCTCC
D 1 OFF ON OFF/ON * N Y/N
D 2 ON ON ON N Y/N
D3ONOFFONY/NY/N
D4OFFOFFONY/NY/N
D 5 OFF OFF OFF Y/N Y/N
P/N – OFF ON OFF
R OFF ON OFF N
RLO OFF ON OFF Y
* High Range Solenoid C 'ON' (for engine braking)
* High Range Solenoid C 'OFF' (no engine braking)
Gear Selector
Lever Position
Gear Solenoids
High Range
ABCTCC
D5–––N
D4–––N
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-38 DESCRIPTION AND OPERATION
1st Gear (D Selected)
Drive – The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is
transmitted through clutch 'C1', 'CC1' and freewheel clutch 'FW1' to the rear input sun gear. The freewheel clutch
'FW4' holds the planetary carrier stationary.
The shift solenoids are applied as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is ON (energised)
l Shift solenoid 'C' is ON/OFF (energised/de-energised).
NOTE: The clutches 'C1', 'CC1' and 'LBC' are applied without damping from the accumulators.
The torque converter lock-up clutch is not applied in 1st gear high range.
Coast – The gear selector lever and manual selector valve spool are in the 'D' position. The planetary carrier is held
stationary by the 'LBC' clutch. Freewheel clutch 'FW4' has no effect. Clutch 'CC1' transmits torque from the rear input
sun gear to the engine input shaft. Clutch 'C1' is applied to hold freewheel clutch 'FW1' outer race stationary which
becomes ineffective. Freewheel clutches 'FW2' and 'FW3' are overrunning (freewheeling).
The shift solenoids are applied as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is ON (energised)
l Shift solenoid 'C' is ON (energised).
NOTE: The torque converter lock-up clutch is not applied in 1st gear high range.
M44 1776
2
3
1
4
5
CC1
C1
FW1
FW3
FW4
FW2
LBC
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-39
2nd Gear (D Selected)
Drive – The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is
transmitted through clutch 'C1', 'CC1' and freewheel clutch 'FW1' to the rear input sun gear. Clutch 'C2' and freewheel
clutch 'FW2' hold the front ring gear stationary. Freewheel clutch 'FW4' is overrunning (freewheeling). The
accumulator for clutch 'C2' operates to smooth the transition from 1st to 2nd gear.
NOTE: The clutch 'CC2' is applied without damping from the accumulator.
The shift solenoids are applied as follows:
l Shift solenoid 'A' is ON (energised)
l Shift solenoid 'B' is ON (energised)
l Shift solenoid 'C' is ON (energised).
NOTE: The torque converter clutch is not applied in 2nd gear high range.
Coast – The gear selector lever and the manual selector valve spool are in the 'D' position. The planetary front ring
gear is held stationary by clutch 'CC2'. Clutch 'CC1' transmits torque from the rear input sun gear to the engine input
shaft. Clutch 'C2' is applied to hold freewheel clutch 'FW2' outer race stationary which becomes ineffective. Freewheel
clutches 'FW3' and 'FW4' are overrunning (freewheeling).
The shift solenoids are applied as follows:
l Shift solenoid 'A' is ON (energised)
l Shift solenoid 'B' is ON (energised)
l Shift solenoid 'C' is ON (energised).
NOTE: The torque converter clutch is not applied in 2nd gear high range.
M44 1777
2
3
1
4
5
CC1
C1
FW1
FW3
FW4
FW2
C2
CC2
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-40 DESCRIPTION AND OPERATION
3rd Gear (D Selected)
Drive – The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is
transmitted the clutch 'C1', 'CC1' and freewheel clutch 'FW1' to the rear input sun gear. Clutch 'CI' and freewheel
clutch 'FW3' hold the front input sun gear stationary. The clutch 'C2' is applied to hold the freewheel clutch 'FW2' outer
race stationary. Freewheel clutch 'FW2' is overrunning (freewheeling). The accumulator for clutch 'CI' operates to
smooth the transition from 2nd to 3rd gear. Freewheel clutch 'FW4' is overrunning (freewheeling).
The shift solenoids are applied as follows:
l Shift solenoid 'A' is ON (energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is ON (energised).
From 3rd gear shifting the torque converter lock-up clutch can be applied or released by the torque converter clutch
solenoid.
Coast – The gear selector lever and manual selector valve spool are in the 'D' position. The front input sun gear is
held stationary by clutch 'COD'. Freewheel clutch 'FW3' has no effect. Clutch 'CC1' transmits torque from the rear
input sun gear to the engine input shaft. Freewheel clutch 'FW1' has no effect. Clutch 'C2' is applied to hold freewheel
clutch 'FW2' outer race stationary. Freewheel clutches 'FW2' and 'FW4' are overrunning (freewheeling).
The shift solenoids are applied as follows:
l Shift solenoid 'A' is ON (energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is ON (energised).
From 3rd gear shifting the torque converter lock-up clutch can be applied or released by the torque converter clutch
solenoid.
M44 1778
2
3
1
4
5
CC1
C1
FW1
FW3
FW4
FW2
CI
COD
C2
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-41
4th Gear (D Selected)
Drive – The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is
transmitted through clutch 'C1', 'CC1' and freewheel clutch 'FW1' to the rear input sun gear. The 'CD' clutch transmits
torque to the planetary carrier, enabling a 1:1 ratio. Clutch 'C2' is applied to hold freewheel clutch 'FW2' outer race
stationary. Freewheel clutch 'FW2' is overrunning (freewheeling). The 'CI' clutch is applied to hold freewheel clutch
'FW3' outer race stationary. The freewheel clutches ”FW3' and FW4' are overrunning (freewheeling).
The accumulator for clutch 'CD' operates to smooth the transition from 3rd to 4th gear.
The shift solenoids are applied as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is ON (energised).
From 3rd gear shifting the torque converter lock-up clutch can be applied or released by the torque converter clutch
solenoid.
Coast – The gear selector lever and the manual selector valve spool are in the 'D' position. Clutch 'CC1' transmits
torque from the rear input sun gear to the engine input shaft. Freewheel clutch 'FW1' has no effect. The clutch 'CD'
transmits torque from the planetary carrier to the engine input shaft, enabling the 1:1 ratio. Clutch 'C2' is applied to
hold freewheel clutch 'FW2' outer race stationary. Freewheel clutch 'FW2' is overrunning (freewheeling). The 'CI'
clutch is applied to hold freewheel clutch 'FW3' outer race stationary. Freewheel clutches 'FW3' and 'FW4' are
overrunning (freewheeling).
The shift solenoids are applied as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is ON (energised).
From 3rd gear shifting the torque converter lock-up clutch can be applied or released by the torque converter clutch
solenoid.
M44 1779
2
3
1
4
5
CC1
C1
CD
FW1
FW3
FW4
FW2
CI
C2
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-42 DESCRIPTION AND OPERATION
5th Gear (D Selected)
Drive – The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is
transmitted through clutch 'CD' to the planetary carrier. Clutch 'COD' holds the front input sun gear stationary. Clutch
'C1' is applied to hold freewheel clutch 'FW1' outer race stationary. Freewheel clutch 'FW1' is overrunning
(freewheeling). Clutch 'C2' is applied to hold freewheel clutch 'FW2' outer race stationary. The freewheel clutch 'FW2'
is overrunning (freewheeling). The 'CI' clutch is applied to hold freewheel clutch 'FW3' outer race stationary. The
freewheel clutches ”FW3' and FW4' are overrunning (freewheeling). Clutch 'CC1' is released.
The accumulator for clutch 'COD' operates to smooth the transition from 4th to 5th gear.
The shift solenoids are applied as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is OFF (de-energised).
From 3rd gear shifting the torque converter lock-up clutch can be applied or released by the torque converter clutch
solenoid.
Coast – The gear selector lever and the manual selector valve spool are in the 'D' position. The 'CD' clutch transmits
torque from the planetary carrier to the engine input shaft. The 'COD' clutch holds the front input sun gear stationary
through the freewheel clutch 'FW3' inner race. The 'C1' clutch is applied to hold the freewheel clutch 'FW1' outer race
stationary. The freewheel clutch 'FW1' is overrunning (freewheeling). The 'CI' clutch is applied to hold the freewheel
clutch 'FW3' outer race stationary and the clutch 'COD' holds the freewheel clutch 'FW3' inner race stationary. The
freewheel clutch 'FW3' becomes ineffective. The freewheel clutch 'FW4' is overrunning (freewheeling).
The shift solenoids are applied as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is OFF (de-energised).
From 3rd gear shifting the torque converter lock-up clutch can be applied or released by the torque converter clutch
solenoid.
M44 1780
2
3
1
4
5
C1
CD
FW1
FW3
FW4
FW2
CI
COD
C2
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-43
Reverse Gear
Drive – The gear selector lever and the manual selector valve spool are in the 'R' position. Engine torque is
transmitted through clutch 'CR' to the front input sun gear. The clutch 'LBC' holds the planetary carrier stationary. The
clutch 'CR' is applied without damping from the accumulator.
The reverse gear is selected using hydraulic selections only.
The shift solenoids are energised as follows:
l Shift solenoid 'A' is OFF/ON (de-energised/energised)
l Shift solenoid 'B' is OFF/ON (de-energised/energised)
l Shift solenoid 'C' is OFF/ON (de-energised/energised).
NOTE: The torque converter lock-up clutch is not applied in reverse gear.
Coast – The gear selector lever and the manual selector valve spool are in the 'R' position. The clutch 'CR' transmits
torque from the front input sun gear to the engine input shaft. The clutch 'LBC' holds the planetary carrier stationary.
NOTE: The clutch 'CR' is applied without damping from the accumulators.
The reverse gear is selected using hydraulic selections only.
The shift solenoids are energised as follows:
l Shift solenoid 'A' is OFF/ON (de-energised/energised)
l Shift solenoid 'B' is OFF/ON (de-energised/energised)
l Shift solenoid 'C' is OFF/ON (de-energised/energised).
NOTE: The torque converter lock-up clutch is not applied in reverse gear.
Park
The gear selector lever and the manual selector valve spool are in the 'P' PARK position. In this condition no clutches
or freewheel clutches are applied. The engine input shaft rotates freely and the planetary carrier output shaft is held
stationary by the parking lock pawl.
The shift solenoids are energised as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is ON (energised)
l Shift solenoid 'C' is OFF (de-energised).
Neutral
The gear selector lever and the manual selector valve spool are in the 'N' NEUTRAL position. In this condition no
clutches or freewheel clutches are applied. The engine input shaft rotates freely with no torque transferred to the
output shaft.
The shift solenoids are energised as follows:
l Shift solenoid 'A' is OFF/ON (de-energised/energised)
l Shift solenoid 'B' is OFF/ON (de-energised/energised)
l Shift solenoid 'C' is OFF/ON (de-energised/energised).
M44 1781
2
3
1
4
5
CC1
C1
CD
CR
FW1
FW3
FW4
FW2
CI
COD
LBC
C2
CC2
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-44 DESCRIPTION AND OPERATION
Default Mode
The shift solenoids are energised as follows:
l Shift solenoid 'A' is OFF (de-energised)
l Shift solenoid 'B' is OFF (de-energised)
l Shift solenoid 'C' is OFF (de-energised)
The EAT ECU cannot operate the torque converter clutch solenoid, so torque converter lock-up is not available.
When default mode occurs when driving (no EAT ECU signal to the shift solenoid valve), the transmission will shift to
5th gear. Powerflow diagram and drive description is the same as described for 5th gear.
When the engine is switched off and then on, 4th gear will be selected. Powerflow diagram and drive description is
the same as described for 4th gear.
Sensors
The transmission contains two speed sensors and a transmission temperature sensor. These sensors are located
inside the transmission, with only the speed sensors being serviceable items. The sensors play an important part in
the operation of the transmission and provide signal information to the EAT ECU. This information is used by the EAT
ECU to control shift timing, fluid temperature and provide the optimum operating condition for the transmission.
Speed Sensors
The speed sensors are used to by the EAT ECU to monitor the input shaft and output shaft speeds.
The input shaft speed is monitored to allow the EAT ECU to calculate the slip of the torque converter clutch and
internal clutch slip. This allows the EAT ECU to accurately control the slip time during shifts and alter the clutch
application or release pressure for overlap shift control.
M44 1782
2
3
1
4
5
7
8
6
9
10
11
12
13
14
15
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-45
The output shaft speed is monitored by the EAT ECU and compared to engine speed signals received from the ECM
on the CAN. These two signals allow the EAT ECU to calculate the transmission slip ratio for plausibility and maintain
adaptive pressure control.
Both speed sensors are identical and are located in the main casing and secured with a screw. One sensor is mounted
at the front of the transmission and monitors input shaft speed from a toothed target wheel located on the rear of the
reverse clutch drum. The second sensor is located at the rear of the transmission and is fitted with a spacer. This
sensor monitors the output shaft speed from the teeth on the ring gear of the planetary gearset.
The speed sensors are of the inductive type and are connected to the EAT ECU by two wires. The sensor receives a
DC supply current from the EAT ECU on one of the wires. As the teeth of the target wheel pass the sensor tip, a
change in the magnetic field of the sensor occurs and results in an AC pulse being generated in the sensor field
winding. This pulse is passed on the second wire and detected by the EAT ECU which processes the signal to
calculate the rotational speed. The AC pulse is proportional to the transmission speed and the EAT ECU measures
the peak to peak outputs of the AC waveform to calculate the rotational speed being measured.
The resistance of the coil winding is between 324 and 486 Ω at 20°C (68°F). Failure of a speed sensor will cause the
EAT ECU to store a related fault code.
Transmission Temperature Sensor
The temperature sensor is located inside the wiring harness in the fluid pan and is connected to the EAT ECU via two
wires. The sensor is a Negative Temperature Co-efficient (NTC) sensor which has a semi-conductor material which
decreases its resistance as the temperature increases.
The EAT ECU supplies a predetermined voltage to the sensor and monitors the returned signal. The voltage drop
caused by the resistance across the sensor is measured and from this the fluid temperature can be calculated.
In the case of low fluid temperatures the ECU will prohibit torque converter lock-up to promote faster fluid warm up.
In the case of high fluid temperatures the ECU increase the torque converter lock-up control and modifies the shift
programme to reduce the fluid temperature.
If the sensor fails the EAT ECU will use a default temperature value. The default value is determined by engine coolant
temperature signals received on the CAN from the ECM. A fault code is stored by the ECM which can retrieved using
TestBook.
The resistance of the semi-conductor material is between 3.12 and 3.565 kΩ at 20°C (68°F).
M44 1784
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-46 DESCRIPTION AND OPERATION
Inhibitor Switch
The inhibitor switch is located internally on the left hand side of the transmission. It is connected via a selector shaft
which rotates with the position of the selector lever. The switch allows the EAT ECU to monitor the position of the
manual selector spool valve and the selected drive program.
The switch is connected to the EAT ECU via six wires and a multiplug. One of the wires supplies a 12V supply to the
switch. The remaining wires are connected to ground within the EAT ECU. When the selector lever is moved to the
selected position, one or more contacts within the switch are made completing a circuit back to the ECU. From the
switch contacts which are made, the ECU determines which selection is required and responds accordingly.
When the selector lever is in Park, the EAT ECU transmits a signal to the immobilisation ECU to enable starter
operation.
The following table shows which switch contacts are made for a given selector lever position.
Inhibitor Switch Track N/P A B C P
EAT ECU Connector 4 Pins Pin 2 Pin 14 Pin 15 Pin 16 Pin 17
Transmission Harness
Connector Pins
4 16 7 19 11
PARK XX X
REVERSE XX
NEUTRAL XXX
DRIVE XX
X = High signal
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-47
Fluid Cooling
1 Fluid feed
2 Fluid return
3 Transmission fluid cooler
4 Engine coolant feed
5 Engine coolant return
The fluid cooler is located on the left hand side of the engine and is attached to the sump near the front of the engine.
The cooler is cooled by engine coolant which flows in a water jacket around cores within the cooler body.
Transmission fluid enters the cooler and flows through the cores where it is cooled by the engine coolant. The fluid
leaves the cooler and is passed back to lubricate the transmission before it returns to the transmission sump.
The fluid cooler receives its engine coolant supply from the radiator via a hose into a quick release fitting on the side
of the cooler. The coolant flows through the cooler and exits via another hose on the forward face of the cooler, where
it is passed through the engine coolant circuit.
The fluid cooler has a thermostatic valve which is opened by transmission fluid temperature. The thermostatic valve
is opened at a transmission fluid temperature of between 91 and 95°C (196 and 203°F) and allows engine coolant to
flow through the fluid cooler.
M44 1788A
3
5
4
1
3
1
2
2
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-48 DESCRIPTION AND OPERATION
Gear Selector Lever Assembly
1 Selector cable
2 Shift interlock solenoid
3 Selector lever
4 Manual +/– Steptronic switch
5 Selector knob and shroud
6 Park/Reverse release button
7 Selector lever cover
8 High/Low range selector switch
9 Selector position LED display
10 Hill Descent Control (HDC) switch
11 Key interlock cable
12 Key interlock mechanism
13 Selector lever position switch
14 Manual/Sport switch
15 Mounting plate
The gear selector lever assembly is located in a central position on the transmission tunnel, between the front driver
and passenger seats. A mounting plate is secured to the transmission tunnel and provides the mounting for the
selector lever assembly.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-49
The selector lever comprises a cast mounting plate which provides for the location of the selector components. The
lever is connected to a gimbal mechanism which allows for the selection of P, R, N, D in a forward or backward
direction and selection between automatic and manual/sport in a left/right transverse direction. When manual/sport
mode is selected, the lever can be moved in a forward or backward direction to select + or – for manual (Steptronic)
operation.
When the selector lever is moved to the M/S position, the Bowden cable to the transmission is mechanically
disconnected at the shifter. If left in Sport mode all gear changes are performed automatically. If Manual (Steptronic)
mode is selected, all gear changes are based on switched ground inputs received by the EAT ECU from the Manual
+/– Steptronic switch.
The selector mechanism houses the following components:
l Manual +/– Steptronic switch
l Shift interlock solenoid
l High/Low range selector switch
l Hill Descent Control (HDC) switch
l Selector position LED display
l Selector lever position switch
l Manual/Sport switch
l Key interlock mechanism.
There are four selector lever positions and two additional positions for manual/sport operation:
l P (Park) – Prevents the vehicle from moving by locking the transmission
l R (Reverse) – Select only when the vehicle is stationary and the engine is at idle – selects reverse direction
l N (Neutral) – No torque transmitted to drive wheels
l D (Drive) – This position uses all five forward gears in high and low ranges
l M/S (Sport mode) – This position uses all five forward gears as in 'D', but will upshift at higher engine speeds
improving acceleration
l + and – ('Steptronic' mode)– Movement of the selector lever in the +/– positions, when the lever is in the M/S
position, will operate the transmission in manual (Steptronic) mode, allowing the driver to manually select all five
forward gears.
The selector lever position is displayed to the driver on the selector position LED display and in the instrument
pack. In 'Steptronic' mode, if a gear is selected, but the EAT ECU logic prevents selection of that gear, the
requested gear is initially displayed. The EAT ECU will engage the next allowed gear and then display that gear.
Manual +/– Steptronic Switch
The manual +/– switch is located on the left hand side of the selector lever assembly. The switch comprises a housing
which provides the location for a sliding contact. When the selector lever is moved to the manual/sport position, a dog
on the lever engages with a slotted abutment on the switch sliding contact. When the lever is moved to the + or –
position the dog moves the switch completing a momentary earth circuit with one of two microswitches at each end
of the switch which correspond to the + or – positions.
This momentary signal is received by the EAT ECU which, on first operation of the switch, initiates manual mode and
operates the transmission in the selected gear.
In this position, a spring will move the selector lever to the centre position when released.
Shift Interlock Solenoid
The shift interlock solenoid is located at the front of the selector lever assembly. The selector lever is connected to a
locking plate which has two holes which correspond to the 'P' and 'N' positions. When the ignition is on or the engine
is running, the solenoid is energised by the EAT ECU when the selector lever is in the 'P' or 'N' positions. When
energised, the solenoid ejects a pin which engages in the locking plate preventing the lever from being moved.
When the footbrake is applied, a signal from a brake switch is passed to the EAT ECU which de-energises the
solenoid allowing the lever to be moved from the 'P' or 'N' position. This prevents the selector from being moved to
the 'D' or 'R' position unintentionally and the application of the brakes also prevents the vehicle 'creeping' when the
gear is engaged.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-50 DESCRIPTION AND OPERATION
High/Low Range Selector Switch
The high/low range switch is located on the selector lever cover, on the right hand side of the selector lever. The switch
can be identified by the a high/low range legend graphic and the switch lever is coloured white. High or low range can
be selected using this switch providing the vehicle speed is within defined limits and the gear selector lever is in the
neutral position.
+ TRANSFER BOX, DESCRIPTION AND OPERATION, Description.
Hill Descent Control (HDC) Switch
The HDC switch is located on the selector lever cover, on the left hand side of the selector lever. The switch can be
identified by the HDC legend graphic and the switch lever is coloured yellow. Operation of the HDC switch is not
directly related to automatic transmission operation.
+ BRAKES, DESCRIPTION AND OPERATION, Foundation Brakes.
Selector Position LED Display
The selector position LED display is located on the selector lever cover, between the HDC and high/low range
switches. The display has a graphic which shows the lever positions P, R, N, D, M/S and +/–. The P, R, N, D and M/
S positions each have a small, red LED which illuminates when that position is selected. The +/– positions do not have
an LED.
The LED display is controlled by the selector lever position switch, with the two components connected via a five wire
ribbon cable. The LED display is powered from the Body Control Unit (BCU) and remains illuminated until the BCU is
in sleep mode. The LED display is active at all times when the ignition is on.
Selector Lever Position Switch
The selector lever position switch is located on the right hand side of the selector lever assembly. The switch has a
moving contact which is connected to the selector lever. As the lever is moved, the sliding contact moves in the switch
completing a circuit with four further contacts in the switch which represent the four lever positions; P, R, N and D.
The switch is connected to the selector position LED display via a ribbon cable and provides the power for the display
LED's. The switch receives its power supply from the BCU.
Manual/Sport Switch
The manual/sport switch is located at the rear of the selector lever assembly. The manual/sport switch is a cam
operated microswitch. A lever with a roller is attached to the switch body. When the selector lever is moved from the
automatic 'D' position to the manual/sport 'M/S' position, the roller contacts a cam on the selector lever which
depresses the switch lever and operates the switch. The switch contacts remain closed when the selector lever is in
the manual/sport position.
The operation of the switch completes an earth path which is sensed by the EAT ECU which switches the transmission
operation to sport when ’M/S’ is selected and deselects sport mode when ’D’ (automatic operation) is reselected. The
completed earth path is connected to the EAT ECU via the M/S LED on the selector lever display which is illuminated
by an output from the ECU when M/S is selected.
Selector Cable
The selector cable is a Bowden type cable that connects the selector lever to the manual selector spool valve. A ’C’
clip secures the outer cable to the selector lever assembly. The inner cable is secured to an arm which is connected
to the selector lever via a 'U' shaped bracket and pin.
The transmission end of the outer cable is secured to a bracket on the transmission by a clamp nut. The transmission
has an operating lever which is attached to and operates the manual selector control spool valve. The inner cable is
attached to the operating lever by a clamp bush and locknut. The clamp bush allows for the adjustment of the selector
cable.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-51
Key Interlock Mechanism
1 Ignition key
2 Ignition switch
3 Bowden cable
4 Latch gate
5 Selector lever assembly
The key interlock mechanism prevents the key from being removed from the ignition switch when the selector lever
is any position other than 'P' PARK. This prevents the vehicle being accidentally left in neutral which would cause the
vehicle to move if the handbrake was not applied.
The mechanical mechanism is operated by a Bowden cable which is attached between the selector lever assembly
and the ignition switch. When the ignition switch is turned to the on position, the switch rotates a lever which in turn
pulls the cable. This lifts a latch in the selector lever assembly which is engaged with the selector lever when in the
'P' position.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-52 DESCRIPTION AND OPERATION
Instrument Pack
1 Instrument pack
2 Transmission status display
3 Message centre
4 Malfunction Indicator Lamp (MIL)
The instrument pack is connected to the EAT ECU via the CAN. Transmission status is transmitted by the EAT ECU
and displayed to the driver on one of two displays in the instrument pack.
+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
Malfunction Indicator Lamp (MIL)
The MIL is located in the lower left hand corner of the instrument pack, below the fuel gauge. Transmission related
faults which may affect the vehicle emissions output will illuminate the MIL.
The MIL is illuminated by the ECM on receipt of a relevant fault message from the EAT ECU on the CAN. The nature
of the fault can be diagnosed using TestBook which reads fault codes stored in the ECU memory.
Transmission Status Display
The transmission status display is located on the right hand side of the instrument pack, below the tachometer. The
display shows the selector lever position and in the case of manual (Steptronic) mode, the selected gear. The selector
lever position and gear selected displays are illuminated in a green colour when active.
70
1/2
1/2
1
/1
1/1
MPH
MPH
10
90
50
50
30
30
110
130
150
M44 1910
4
3
2
1
Symbol Description
P Park selected
R Reverse selected
N Neutral selected
D Drive selected
1 1st gear selected (Manual mode)
2 2nd gear selected (Manual mode)
3 3rd gear selected (Manual mode)
4 4th gear selected (Manual mode)
5 5th gear selected (Manual mode)
Low range selected. Flashes when
changing from low to high range.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-53
Additionally, the display also shows a low range symbol when low range is selected on. The low range symbol is
illuminated in an amber colour when active. When the transfer box is changing from low to high range, the low range
symbol flashes until the range change is complete.
Message Centre Display
The message centre is located below the speedometer and the tachometer at the bottom of the instrument pack. The
message centre is a Liquid Crystal Display (LCD) to relay vehicle status information to the driver. The message centre
can display the following transmission related messages:
l SPORT MODE
l MANUAL MODE
l SELECT NEUTRAL
l TRANSMISS'N OVERHEAT
l TRANSMISS'N FAILSAFE PROG
l LOW RANGE
l HIGH RANGE
l SLOW DOWN
l SELECT NEUTRAL.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-54 DESCRIPTION AND OPERATION
EAT ECU
1 EAT ECU
2 E-box
3 ECM
The EAT ECU is the main unit for controlling the transmission operation. The ECU software was designed in
conjunction with Land Rover, Siemens and General Motors Powertrain.
The EAT ECU is located in the E-box which is located forward of the RH suspension top mount. The ECU is secured
in a clip which is positioned adjacent to the ECM in the E-box. The ECU has blue connector socket colour which
assists identification.
The E-box has a temperature controlled environment which maintains the optimum temperature for ECU operation.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-55
Inputs and Outputs
The sensor signals allow the EAT ECU to monitor the transmission operation. The ECU processes the incoming
signals and compares this information with data stored in its memory. If the received signals are not within the stored
values, the ECU will make adjustments to the transmission operation using the solenoids to provide optimum
driveability and performance.
The sensor inputs provide the EAT ECU with a constant update of the operating condition of the transmission and the
engine. The ECU compares this input data with mapped information stored in its memory and will make any required
adjustment to the operation of the transmission by operating the solenoids.
The EAT ECU uses three harness connectors for all input and output information.
EAT ECU Harness Connector C0193 Pin Details
EAT ECU Harness Connector C0932 Pin Details
Pin No. Description Input/Output
1 Ground for shift interlock solenoid Input
2 Power supply for shift interlock solenoid Output
3 Park signal to steering lock ECU Output
4 to 8 Not used –
9 Range change request 1 Output
10 Range change request 2 Output
11 to 17 Not used –
18 High/Low range switch Input
19 Selector manual Steptronic switch UP Input
20 Selector manual Steptronic switch DOWN Input
21 to 52 Not used –
Pin No. Description Input/Output
1 Ignition power supply Input
2 and 3 Not used –
4 Electronic ground –
5 Power ground –
6 Power ground –
7 Permanent battery power supply Input
8 Power supply from main relay Input
9 Power supply from main relay Input
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-56 DESCRIPTION AND OPERATION
EAT ECU Harness Connector C1835 Pin Details
Main Relay
The main relay is located inside the E-box and is identified by its blue colour. The relay is connected direct from the
battery via a 100 Amp remote fuse, located behind the battery, adjacent to the transfer box ECU. The relay coil is
controlled by the ECM which provides a ground for the coil when the relay is to be energised.
When energised the main relay supplies battery voltage, via fuse 4 in the engine compartment fusebox, to the EAT
ECU.
Diagnostics
The diagnostic socket is located in the fascia, in the driver's side stowage tray. The socket is secured in the fascia
panel and protected by a hinged cover.
Pin No. Description Input/Output
1 Neutral/Park selected signal Input
2 Ignition supply to inhibitor switch Output
3 Power supply for solenoids Output
4 and 5 Not used –
6 Ground for TCC PWM Solenoid Input
7 Not used –
8 Ground for pressure regulator solenoid Input
9 Ground for shift valve solenoid C Input
10 Ground for shift valve solenoid B Input
11 Power supply for pressure regulator solenoid Output
12 and 13 Not used –
14 Inhibitor switch track A Input
15 Inhibitor switch track B Input
16 Inhibitor switch track C Input
17 Inhibitor switch track P Input
18 Power supply for temperature sensor Output
19 Temperature sensor analogue signal Input
20 Ground for shift valve solenoid A Input
21 and 22 Not used –
23 Input shaft speed sensor supply Output
24 Input shaft speed sensor signal Input
25 Input shaft speed sensor screen –
26 to 31 Not used –
32 Diagnostic K line (via ECM) Input/Output
33 to 35 Not used –
36 CAN bus high Input/Output
37 CAN bus low Input/Output
38 Output shaft speed sensor screen –
39 Output shaft speed sensor signal Input
40 Output shaft speed sensor supply Output
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-57
Diagnostic Socket
1 Cover 2 Diagnostic socket
The diagnostic socket allows the exchange of information between the various ECU's on the bus systems and
TestBook or a diagnostic tool using Keyword 2000 protocol. The information is communicated to the socket via a
diagnostic ISO9141 K Line. This allows the retrieval of diagnostic information and programming of certain functions
using TestBook or a suitable diagnostic tool.
The EAT ECU uses a P Code strategy which stores industry standard and Land Rover specific Diagnostic Trouble
Codes (DTC) relating to faults.
Controller Area Network (CAN) Bus
The CAN bus is a high speed broadcast network connected between the following electronic units:
l EAT ECU
l ECM
l Transfer box ECU
l Air suspension ECU
l Instrument pack
l ABS ECU
l Steering angle ECU.
The CAN allows the fast exchange of data between ECU's every few microseconds. The bus comprises two wires
which are identified as CAN high (H) and CAN low (L). The two wires are coloured yellow/black (H) and yellow/brown
(L) and are twisted together to minimise electromagnetic interference (noise) produced by the CAN messages.
+ COMMUNICATION DATA BUSES, DESCRIPTION AND OPERATION, Description.
In the event of a CAN bus failure the following symptoms may be observed:
l Transmission operates in default mode
l Torque converter lock-up control is disabled
l ECM to EAT ECU engine torque reduction message inoperative
l Gear position display in instrument pack inoperative.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-58 DESCRIPTION AND OPERATION
Operation
Driving Modes
There are a number of different driving modes of operation. Some can be selected by the driver and some are
automatically initiated by the EAT ECU during driving:
l Normal mode
l Sport mode
l Manual (Steptronic) mode
l Hill Descent Control (HDC) mode
l Cruise mode
l Hill mode
l Default (Limp home) mode
l Reverse lock-out mode
l Cooling strategy.
Normal Mode
Normal mode is automatically selected by the EAT ECU on power up. In this mode all automatic and adaptive modes
are active. Normal mode uses gear shift and lock-up maps to allow vehicle operation which is a compromise between
performance, fuel consumption and emissions. If the transmission is operated in sport or manual mode and the
selector lever is moved to the 'D' position, normal mode is automatically resumed.
Sport Mode
The sport mode operates in high range only and provides enhanced acceleration and responsiveness. In sport mode
the EAT ECU uses shift maps which allow the transmission to downshift more readily, hold gears for longer at higher
engine speeds, and limits the transmission to 4th gear.
Sport mode is selected by moving the selector lever to the left into the 'M/S' position. When the sport mode is first
selected, 'SPORT' is displayed in the message centre for 6 seconds and, if 5th gear is currently engaged, the EAT
ECU downshifts to 4th.
Manual (Steptronic) Mode
Manual mode allows the transmission to operate as a semi-automatic 'Steptronic' unit. The driver can change up and
down the five forward gears with the freedom of a manual transmission.
Shift maps are provided for manual mode to protect the engine at high engine speeds. The EAT ECU will automatically
change up to a higher gear ratio to prevent engine overspeed and change down to a lower gear ratio to avoid engine
labouring and stalling.
When kickdown is requested the EAT ECU downshifts at least 2 gears.
When the vehicle is stationary, to drive off the driver can select 1st or 2nd gear in high range, or 1st, 2nd or 3rd gear
in low range. Any other gear selection will be rejected by the EAT ECU.
When driving off, upshifts can be pre-selected by making + selections with the selector lever for the number of upshifts
required. The EAT ECU then automatically performs a corresponding number of upshifts when the appropriate shift
points are reached. So, for example, when starting off in 1st gear, if three + selections are made in quick succession,
the EAT ECU will automatically change up through the box to 4th gear as the vehicle accelerates, without any further
selections being made.
In manual mode a low gear can be selected to provide engine braking for descending a slope without HDC or
continuous use of the brake pedal. The driver can prepare for the end of the descent by moving the selector lever to
D. The EAT ECU will maintain the low gear and only revert to automatic shift control when the throttle is opened and
vehicle speed increases.
AUTOMATIC TRANSMISSION – GM 5L40-E
DESCRIPTION AND OPERATION 44-1-59
HDC Mode
The HDC mode assists the ABS ECU in controlling the downhill speed of the vehicle. When HDC is selected on, the
EAT ECU selects the most appropriate gear for the descent, to maximise engine braking.
Cruise Mode
When cruise control is activated, the EAT ECU receives a cruise active message on the CAN. The EAT ECU activates
a cruise control map which prevents locking and unlocking of the torque converter clutch and minimises up and down
shifts. If cruise control is operative and the vehicle speed increases due to coasting downhill, the ECM can request a
down shift via a CAN message if the vehicle speed exceeds the set cruise limit.
Hill Mode
Hill mode is initiated by the EAT ECU when high engine torque, high throttle angle and low engine speed is detected
via ECM signals on the CAN. The EAT ECU defines this combination of signals to determine when the vehicle is
travelling on a steep gradient.
In hill mode the EAT ECU adopts one of three shift maps which hold the transmission in low gears throughout the
ascent. The shift map chosen depends on the severity of the slope as determined from the engine signals.
Hill mode can also be initiated when the vehicle is at very high altitudes.
Default (Limp Home) Mode
If a transmission fault is detected by the EAT ECU, the ECU adopts a limp home mode strategy. 'TRANS.FAILSAFE'
is displayed in the message centre and, if the fault has an effect on engine emissions, the MIL will also be illuminated.
In default mode, P, R and N functions operate normally (if the fault allows these selections) and the EAT ECU locks
the transmission in 5th gear to allow the driver to take the vehicle to the nearest dealer. The torque converter lock-up
clutch is disabled and reverse lock-out will not function.
If the vehicle is stopped and subsequently restarted in the default mode condition, the EAT ECU operates normally
until the fault which caused the condition is detected again.
Reverse Lock-Out Mode
When the vehicle is travelling forwards, selecting reverse could cause transmission damage. To protect against this,
reverse gear is prohibited if the vehicle is travelling forwards at a road speed above 5 mph (8 km/h).
Cooling Strategy
The purpose of the cooling strategy is to reduce engine and transmission temperatures during high load conditions,
when towing a trailer for example. Under these conditions the engine and transmission may generate excessive heat.
If the transmission fluid temperature increases to 140°C (284°F) or higher, the EAT ECU employs the cooling strategy.
The strategy uses a specific shift and torque converter lock-up clutch map. This map allows torque converter clutch
lock-up and gear shifts to operate outside of their normal operation. This will reduce the engine speed and/or slip in
the torque converter, therefore reducing heat generated by the engine and the transmission.
The cooling strategy is cancelled when the transmission fluid temperature decreases to 130°C (266°F) or below.
Transmission Fault Status
If the EAT ECU detects a fault with the transmission system, it will enter a default mode to prevent further damage to
the transmission and allow the vehicle to be driven.
When a fault is detected a CAN message is sent from the EAT ECU and is received by the instrument pack. The
instrument pack illuminates the MIL and displays 'TRANS.FAILSAFE' in the message centre.
Some transmission faults may not illuminate the MIL or display a fault message, but the driver may notice a reduction
in shift quality.
AUTOMATIC TRANSMISSION – GM 5L40-E
44-1-60 DESCRIPTION AND OPERATION
Engine Speed and Throttle Monitoring
The ECM constantly supplies the EAT ECU with information on engine speed and throttle angle through messages
on the CAN. The EAT ECU uses this information to calculate the correct and appropriate timing of shift changes.
If the messages are not received by the ECM, the EAT ECU will implement a back-up strategy to protect the
transmission from damage and allow the vehicle to be driven.
In the event of an engine speed signal failure, any of the following symptoms may be observed:
l Decrease in fuel economy
l Increase in engine emissions
l Harsh shifting.
In the event of a throttle position signal failure, any of the following symptoms may be observed:
l Harsh shift changes
l No kickdown
l Torque reduction request inhibited
l Decrease in fuel economy.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-1
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AUTOMATIC TRANSM ISSION – ZF 5HP24DESCRIPTIO N AND OPERATION
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-2 DESCRIPTION AND OPERATION
ZF 5HP24 Automatic Transmission
Component Location
RHD model shown
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-3
1 Electronic Automatic Transmission (EAT) ECU
2 Engine Control Module (ECM)
3 Instrument pack
4 Selector lever
5 Transmission
6 Transmission valve block (behind fluid pan)
7 Transmission fluid cooler
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-4 DESCRIPTION AND OPERATION
ZF 5HP24 Automatic Transmission –
Exploded View
Note the transmission shown is exploded to the extent of the serviceable items
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-5
1 Inhibitor switch
2 Screw (2 off)
3 Connector bracket
4 Plug
5 Transmission housing
6 Valve block
7 Shift control solenoids
8 O-ring seals
9 Pressure regulator solenoids
10 Filter
11 Torx screw (2 off)
12 Gasket
13 Fluid pan
14 Torx screw (22 off)
15 Plug
16 Magnet
17 Retaining clip
18 O-ring seal
19 Turbine speed sensor
20 Connector housing
21 O-ring seal (2 off)
22 Wiring harness
23 Output shaft speed sensor
24 Torque converter
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-6 DESCRIPTION AND OPERATION
ZF 5HP24 Automatic Transmission –
Sectional View
24
27
M44 1819
10
1
28
26
2
3
4
5
6
7
8
9
11
12
13
14
15 16
17
18
19
20
21
22
23
25
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-7
1 Torque converter lock-up clutch
2 Torque converter
3 Fluid pump
4 Clutch A
5 Clutch B
6 Clutch C
7 Clutch D
8 Clutch E
9 Planetary gearset 1
10 Planetary gearset 2
11 Planetary gearset 3
12 Clutch F
13 Freewheel clutch – 1st Gear
14 Park lock pawl
15 Speed sensor target wheel
16 Output shaft speed sensor
17 Valve body channel plate
18 Pressure regulator and shift control solenoids
19 Upper valve body
20 Rear lower valve body
21 Fluid filter
22 Forward lower valve body
23 Turbine speed sensor
24 Fluid pan
25 Main casing
26 Fluid pressure control valve
27 Bell housing
28 Input shaft
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-8 DESCRIPTION AND OPERATION
ZF 5HP24 Automatic Transmission –
Valve Block and Solenoid Valves
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-9
1 Valve body channel plate
2 Upper valve body
3 Pressure regulator solenoids
4 Shift control solenoids
5 Rear lower valve body
6 Forward lower valve body
7 Reverse gear valve (reverse protection)
8 Clutch 'D' valve
9 Clutch 'D' holding valve
10 Clutch 'C' damper
11 Pressure regulation dampers
12 Clutch 'D' holding valve
13 Clutch 'B' holding valve
14 Modulation pressure valve
15 Lubrication pressure valve
16 Main pressure valve
17 Torque converter pressure valve
18 Selector valve spool (manually operated)
19 Valve torque converter lock-up clutch
20 Clutch 'A' damper
21 Shift valve 1
22 Shift valve 2
23 Shift valve 3
24 Clutch 'A' valve
25 Cut-off valve 'A'
26 Holding valve 'E'
27 Clutch 'B' valve
28 Pressure reducing valve 2
29 Pressure reducing valve 1
30 Clutch 'E' valve
31 Clutch 'F' valve
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-10 DESCRIPTION AND OPERATION
ZF 5HP24 Automatic Transmission
Control Diagram
A = Hardwired; D = CAN Bus; J = ISO 9141 K Line
M44 1821A
A
J
D
13 12
14
15
16
9
1
2
3
4
5
6
7
8
10
11
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-11
1 Permanent battery supply (30A Fuse)
2 Main relay
3 Battery supply (60A Fusible link)
4 Comfort start relay
5 Temperature sensor
6 Turbine speed sensor
7 Output speed sensor
8 Brake switch
9 Electronic Automatic Transmission (EAT) ECU
10 Inhibitor switch
11 Solenoid valves
12 Engine Control Module (ECM)
13 Instrument pack
14 Diagnostic socket
15 Selector lever range switch
16 Shift interlock solenoid
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-12 DESCRIPTION AND OPERATION
Description
General
The ZF 5HP24 transmission is an electronically controlled, five speed unit for use with the V8 petrol engine. The
transmission is manufactured by ZF Transmissions GmbH in Saarbrücken, Germany.
The transmission is controlled by an Electronic Automatic Transmission (EAT) ECU which contains software to
provide operation as a semi-automatic 'Steptronic' transmission. The EAT ECU allows the transmission to be
operated as a conventional automatic unit by selecting P, R, N, D on the selector lever. Movement of the selector lever
across the gate to the 'M/S' position puts the transmission into electronic 'Sport' mode. Further movement of the lever
in a lateral position to the + or – position puts the transmission into electronic manual 'Steptronic' mode.
The 5HP24 transmission has the following features:
l Designed to be maintenance free
l Transmission fluid is 'fill for life'
l The torque converter features a controlled slip feature with electronically regulated control of lock-up, creating a
smooth transition to the fully locked condition
l Shift programs controlled by the EAT ECU
l Connected to the ECM via the CAN for communications
l Default mode if major faults occur
l Diagnostics available from the EAT ECU via the ISO 9141 K Line.
The gearbox comprises three main casings; the bell housing, the intermediate plate and the main case. These items
are bolted together to form the housing for the transmission components.
A fluid pan is bolted to the lower face of the main case and is secured with bolts. The fluid pan is sealed to the main
case with a gasket. Removal of the fluid pan allows access to the valve block and solenoids and speed sensors. The
fluid pan has four magnets located in each corner which collect any metallic particles present in the transmission fluid.
A non-serviceable fluid filter is located inside the fluid pan. If the transmission fluid becomes contaminated or after
any service work the filter must be replaced.
The bell housing provides protection for the torque converter assembly and also provides the attachment for the
gearbox to the engine block. The torque converter is a non-serviceable assembly which also contains the lock-up
clutch mechanism. The torque converter drives a crescent type pump via drive tangs. The fluid pump is located in the
intermediate plate, between the bell housing and the main case.
The main case contains the following components:
l Input shaft
l Output shaft
l Valve block and solenoids
l Three rotating multiplate drive clutches
l Three fixed multiplate brake clutches
l One freewheel, one way, sprag type clutch
l A planetary gear train comprising three planetary gear sets.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-13
Torque Converter
1 Impeller
2 Freewheel clutch
3 Stator shaft
4 Input shaft
5 Stator
6 Turbine
7 Lockup vibration damper
8 Lock-up clutch piston
9 Converter housing cover
The torque converter is the coupling element between the engine and the gearbox and is located in the bell housing,
on the engine side of the transmission. The driven power from the engine crankshaft is transmitted hydraulically and
mechanically through the torque converter to the transmission. The torque converter is connected to the engine by a
drive plate.
The torque converter comprises an impeller, a stator and a turbine. The torque converter is a sealed unit with all
components located between the converter housing cover and the impeller. The two components are welded together
to form a sealed, fluid filled housing.
9
M44 1822
7
6
8
2
1
3
4
5
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-14 DESCRIPTION AND OPERATION
The converter housing cover has four threaded bosses which provide for attachment of the engine drive plate which
is connected to the engine crankshaft. The threaded bosses also provide for location of special tools which are
required to removed the torque converter from the bell housing. With the impeller welded to the converter housing
cover, the impeller is therefore driven at engine crankshaft speed.
Impeller
The impeller outer body has a boss with two machined slots. The boss locates over the transmission input shaft and
the slots engage with two tangs on the fluid pump. This arrangement allows the fluid pump to be driven at engine
speed.
The impeller comprises a row of blades attached to the outer body. The root of the blades collect fluid which flows by
centrifugal force around the curved outer surface of the impeller to the tip of the blades.
Fluid Flow
Typical torque converter shown
1 Turbine
2 Stator
3 Impeller
When the engine is running the rotating impeller acts as a centrifugal pump, picking up fluid at its centre and
discharging it at high velocity through the blades on its outer rim. The design and shape of the blades and the curve
of the impeller body cause the fluid to rotate in a clockwise direction as it leaves the impeller. This rotation improves
the efficiency of the fluid as it contacts the outer row of blades on the turbine.
The centrifugal force of the fluid leaving the blades of the impeller is passed to the curved inner surface of the turbine
via the tip of the blades. The velocity and clockwise rotation of the fluid causes the turbine to rotate.
Turbine
The turbine is similar in design to the impeller with a continuous row of blades. The fluid from the impeller enters the
turbine through the tip of the blades and is directed around the curved body of the turbine to the root of the blades.
The curved surface redirects the fluid back in the opposite direction to which it entered the turbine, effectively
increasing the turning force applied to the turbine from the impeller. This principle is known as torque multiplication.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-15
When the engine speed increases, the turbine speed also increases. The fluid leaving the inner row of the turbine
blades is rotated in an anti-clockwise direction due to the curve of the turbine and the shape of the blades. The fluid
is now flowing in the opposite direction to the engine rotation and therefore the impeller. If the fluid was allowed to hit
the impeller in this condition, it would have the effect of applying a brake to the impeller, eliminating the torque
multiplication effect. To prevent this, the stator is located between the impeller and the turbine.
Stator
The stator is located on the splined transmission input shaft via a freewheel clutch. The stator comprises a number of
blades which are aligned in an opposite direction to those of the impeller and turbine. The main function of the stator
is to redirect the returning from the turbine, changing its direction to that of the impeller.
The redirected fluid from the stator is directed at the inner row of blades of the impeller, assisting the engine in turning
the impeller. This sequence increases the force of the fluid emitted from the impeller and thereby increases the torque
multiplication effect of the torque converter.
Stator Functions
Typical stator shown
1 Blades
2 Stator held – fluid flow redirected
3 Stator rotates freely
4 Roller clutch
5 Converter at coupling speed
6 Fluid flow from turbine
7 Converter multiplying
8 Fluid flow from impeller
9 Drive from engine
10 Impeller
11 Stator
12 Turbine
13 Output to transmission
Refer to the 'Stator Functions' illustration
Fluid emitted from the impeller acts on the turbine. If the turbine is rotating at a slower speed than the fluid from the
impeller, the fluid will be deflected by the turbine blades in the path 'A'. The fluid is directed at and deflected by the
stator blades from path 'B' to path 'C'. This ensures that the fluid is directed back to the pump in the optimum direction.
In this condition the sprag clutch is engaged and the force of the fluid on the stator blades assists the engine in rotating
the impeller
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-16 DESCRIPTION AND OPERATION
As the rotational speed of the engine and therefore the turbine increases, the direction of the fluid leaving the turbine
changes to path 'D'. The fluid is now directed from the turbine to the opposite side of the stator blades, rotating the
stator in the opposite direction. To prevent the stator from resisting the smooth flow of the fluid from the turbine, the
sprag clutch releases, allowing the stator to rotate freely on it shaft.
When the stator becomes inactive, the torque converter no longer multiples the engine torque. When the torque
converter reaches this operational condition it ceases to multiply the engine torque and acts solely as a fluid coupling,
with the impeller and the turbine rotating at approximately the same speed.
The stator uses a sprag type clutch. When the stator is rotated in a clockwise direction the sprags twist and are
wedged between the inner and outer races. In this condition the sprags transfer the rotation of the outer race to the
inner race which rotates at the same speed. Refer to 'One Way Freewheel Clutch' in this manual for further details of
the sprag type clutch.
Lock-up Clutch Mechanism
The Torque Converter Clutch (TCC) is hydraulically controlled by an electronic pressure regulating solenoid (EPRS4)
which is controlled by the EAT ECU. This allows the torque converter to have three states of operation as follows:
l Fully engaged
l Controlled slip variable engagement
l Fully disengaged.
The TCC is controlled by two hydraulic spool valves located in the valve block. These valves are actuated by pilot
pressure supplied via a solenoid valve which is also located in the valve block. The solenoid valve is operated by PWM
signals from the EAT ECU to give full, partial or no lock-up of the torque converter.
A = Unlocked condition
B = Locked condition
1 Clutch plate
2 Clutch piston
3 Torque converter body
4 Turbine
5 Impeller
6 Stator
7 Piston chamber
8 Turbine chamber
The lock-up clutch is a hydro-mechanical device which eliminates torque converter slip, improving fuel consumption.
The engagement and disengagement is controlled by the EAT ECU to allow a certain amount of controlled 'slip'. This
allows a small difference in the rotational speeds of the impeller and the turbine which results in improved shift quality.
The lock-up clutch comprises a piston and a clutch friction plate.
M44 1824
A
B
1
4
6
5
7
8
1
4
6
5
7
8
2 3
2 3
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-17
In the unlocked condition, the oil pressure supplied to the piston chamber and the turbine chamber is equal.
Pressurised fluid flows through a drilling in the turbine shaft and through the piston chamber to the turbine chamber.
In this condition the clutch plate is held away from the torque converter body and torque converter slip is permitted.
In the locked condition, the TCC spool valves are actuated by the electronic pressure regulating solenoid (EPRS4).
The fluid flow in the unlocked condition is reversed and the piston chamber is vented. Pressurised fluid is directed into
the turbine chamber and is applied to the clutch piston. The piston moves with the pressure and pushes the clutch
plate against the torque converter body. As the pressure increases, the friction between the clutch plate and the body
increases, finally resulting in full lock-up of the clutch plate with the body. In this condition there is direct mechanical
drive from the engine crankshaft to the transmission planetary gear train.
Fluid Pump
The fluid pump is an integral part of the transmission. The fluid pump is used to supply hydraulic pressure for the
operation of the control valves and clutches and also to pass the fluid through the transmission cooler.
The 5HP24 fluid pump is a crescent type pump and is located between the intermediate plate and the torque
converter. The pump has a delivery rate of 16cm
3
per revolution.
1 Securing ring
2 Shaft oil seal
3 O-ring seal
4 Pump housing
5 Ring gear
6 Crescent spacer
7 Roller bearing
8 Impeller
9 Centring pin
10 Spring washer
11 Outlet port (high pressure)
12 Inlet port (low pressure)
The pump is driven by a positive coupling with the torque converter impeller, therefore the pump is driven at engine
crankshaft speed.
The pump comprises a housing, a crescent spacer, an impeller and a ring gear. The housing has inlet and outlet ports
to direct flow and is located in the intermediate plate by a centring pin. The pump action is achieved by the impeller,
ring gear and crescent spacer.
M44 1823
10
4
6
5
8
9
31
7
2
12
5
6
11
8
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-18 DESCRIPTION AND OPERATION
The crescent spacer is fixed in its position by a pin and is located between the ring gear and the impeller. The impeller
is driven by the drive from the torque converter which is located a needle roller bearing in the pump housing. The
impeller teeth mesh with those of the ring gear. When the impeller is rotated, the motion is transferred to the ring gear
which rotates in the same direction.
The rotational motion of the ring gear and the impeller collects fluid from the intake port in the spaces between the
teeth. When the teeth reach the crescent spacer, the oil is trapped in the spaces between the teeth and is carried with
the rotation of the gears. The spacer tapers near the outlet port. This reduces the space between the gear teeth
causing a build up of fluid pressure as the oil reaches the outlet port. When the teeth pass the end of the spacer the
pressurised fluid is passed to the outlet port.
The fluid emerging from the outlet port is passed through the fluid pressure control valve. At high operating speeds
the pressure control valve maintains the output pressure to the gearbox at a predetermined maximum level. Excess
fluid is relieved from the pressure control valve and is directed, via the main pressure valve in the valve block, back
to the pump inlet port. This provides a pressurised feed to the pump inlet which prevents cavitation and reduces pump
noise.
Valve Block and Solenoid Valves
The valve block is located in the bottom of the transmission and is covered by the fluid pan. The valve block houses
electrical actuators, and control valves which provide all electro-hydraulic control for all transmission functions. The
valve block comprises the following components:
l Five pressure regulator solenoids
l Three shift control solenoids
l Six dampers
l Twenty one hydraulic spool valves
l Manually operated selector valve.
Pressure Regulator Solenoids
1 Coil winding
2 Valve
3 Spring
Five Electronic Pressure Regulator Solenoids (EPRS) are located in the valve block. The solenoids are controlled by
PWM signals from the EAT ECU. The solenoids convert the electrical signals into hydraulic control pressure
proportional to the signal to actuate the spool valves for precise transmission operation. EPRS4 is used for pressure
regulation for the torque converter lock-up clutch.
M44 1825
1
23
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-19
Solenoid EPRS1 supplies a lower control pressure as the signal amperage increases. The EPRS1 solenoid is a
normally closed regulating flow solenoid valve and regulates the main line pressure. The solenoid is used for adaptive
pressure control. The EAT ECU operates the solenoid using PWM signals. The EAT ECU monitors engine load and
clutch slip and varies the solenoid duty cycle accordingly.
Solenoids EPRS2, 3 and 5 supply a higher control pressure as the signal amperage increases. The solenoids are
normally open solenoids regulating flow solenoid valves. The solenoids are used to regulate the supply of fluid
pressure for clutch application during overlap up and down shifts of gears 2–3, 3–4 and 4–5. The EAT ECU operates
the solenoids using a PWM earth proportional to the required increasing or decreasing clutch pressures.
The resistance of the coil winding for solenoid EPRS1 is between 5.4 to 6.4Ω at 20°C (68°F). The resistance of the
coil windings for solenoids EPRS2, 3, 4 and 5 is between 5.9 and 6.9Ω at 20°C (68°F).
Shift Control Solenoids
1 Coil winding
2 Valve
3 Spring
Three shift control Solenoid Valves (SV) are located in the valve block. The solenoids are controlled by the EAT ECU
and convert electrical signals into hydraulic control signals to control clutch application.
The shift control solenoids SV1, 2 and 3 are normally closed, on/off solenoids which are controlled by the EAT ECU
switching the solenoid to earth. The EAT ECU also supplies the power to solenoids. The EAT ECU energises the
solenoids in a programmed sequence for clutch application for gear ratio changes and shift control.
The resistance of the coil winding for solenoids SV1, 2 and 3 is between 26 to 30.4Ω at 20°C (68°F).
Dampers
There are six dampers located in the valve block. Four of the dampers are used to regulate and dampen the regulated
pressure supplied via the pressure regulating solenoid valves. The two remaining dampers are used for operation of
clutches 'A' and 'C' and providing damping of the fluid pressure during shift changes. All of the dampers are load
dependent through modulation of the damper against its return spring pressure.
The dampers comprise a piston, a housing bore and a spring. The piston is subject to the pressure applied by the
spring. The bore has a connecting port to the function to which it applies. Fluid pressure applied to the applicable
component (i.e. a clutch) is also subjected to the full area of the piston, which moves against the opposing force
applied by the spring. The movement of the piston creates an action similar to a shock absorber, momentarily delaying
the build up of pressure in the circuit. This results in a more gradual application of clutches improving shift quality.
M44 1826
1
23
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-20 DESCRIPTION AND OPERATION
Spool Valves
The valve block contains twenty one spool valves which control various functions of the transmission. The spool
valves are of conventional design and are operated by fluid pressure.
Each spool valve is located in its spool bore and held in a default (unpressurised) position by a spring. The spool bore
has a number of ports which allow fluid to flow to other valves and clutches to enable transmission operation. Each
spool has a piston which is waisted to allow fluid to be diverted into the applicable ports when the valve is operated.
When fluid pressure moves a spool, one or more ports in the spool bore are covered or uncovered. Fluid is prevented
from flowing or is allowed to flow around the applicable waisted area of the spool and into another uncovered port.
The fluid is either passed through galleries to actuate another spool, operate a clutch or is returned to the fluid pan.
Drive Clutches
Multiplate Drive or Brake Clutch – Typical
1 Input shaft
2 Main pressure supply port
3 Piston
4 Cylinder – External plate carrier
5 Clutch plate assembly
6 Baffle plate
7 Diaphragm spring
8 Output shaft
9 Bearing
10 Dynamic pressure equalisation chamber
11 Piston chamber
12 Lubrication channel
M44 1827
1
10
2
3
4
5
6
7
8
9
11
12
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-21
There are three drive clutches and three brake clutches used in the 5HP24 transmission. Each clutch comprises one
or more friction plates dependent on the output controlled. A typical clutch consists of a number of steel outer plates
and inner plates with friction material bonded to each face.
The clutch plates are held apart mechanically by a diaphragm spring and hydraulically by dynamic pressure. The
pressure is derived from a lubrication channel which supplies fluid to the bearings etc. The fluid is passed via a drilling
in the output shaft into the chamber between the baffle plate and the piston. To prevent inadvertent clutch application
due to pressure build up due to centrifugal force, the fluid in the dynamic pressure equalisation chamber overcomes
any pressure in the piston chamber and holds the piston off the clutch plate assembly.
When clutch application is required, main pressure from the fluid pump is applied to the piston chamber from the
supply port. This main pressure overcomes the low pressure fluid present in the dynamic pressure equalisation
chamber. The piston moves, against the pressure applied by the diaphragm spring, and compresses the clutch plate
assembly. When the main pressure falls, the diaphragm spring pushes the piston away from clutch plate assembly,
disengaging the clutch.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-22 DESCRIPTION AND OPERATION
One Way Free Wheel Clutch – Typical
1 Sprags
2 Inner race
3 Outer race
4 Sprag and cage assembly
5 Sprag outer race
6 Sprag inner race
7 Retaining ring
The 5HP24 transmission uses only one free wheel clutch to perform a component holding function. The free wheel
clutch, in conjunction with the hydraulic clutches, prevent disruption of the power output during shift changes. The
freewheel clutch is located at the rear of the planetary gearset and controls brake clutch 'F'.
The free wheel clutch can perform three functions; hold components stationary, drive components and free wheel
allowing components to rotate without a drive output. The free wheel clutch used in the 5HP24 transmission is of the
sprag type and comprises an inner and outer race and a sprag and cage assembly. The inner and outer races are
pressed into their related components with which they rotate. The sprag and cage assembly is located between the
inner and outer races.
The sprags are located in a cage which is a spring which holds the sprags in the 'wedge' direction and maintains them
in contact with the inner and outer races.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-23
Referring to the illustration, the sprags are designed so that the dimension 'B' is larger than the distance between the
inner and outer race bearing surfaces. When the outer race rotates in a clockwise direction, the sprags twist and the
edges across the dimension 'B' wedge between the races, providing a positive drive through each sprag to the inner
race. The dimension 'A' is smaller than the distance between the inner and outer race bearing surfaces. When the
outer race rotates in an anti-clockwise direction, the dimension 'A' is too small to allow the sprags to wedge between
the races, allowing the outer race to rotate freely.
On the illustration shown, when the outer race is rotated in a clockwise direction, the sprags twist and are 'wedged'
between the inner and outer races. The sprags then transfer the rotation of the outer race to the inner race, which
rotates at the same speed.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-24 DESCRIPTION AND OPERATION
Planetary Gear Train
Planetary Gearset – Sectional View
1 Planetary gearset 1
2 Ring gear 1
3 Ring gear 2
4 Planetary gearset 2
5 Ring gear 3
6 Planetary gearset 3
7 Output shaft
8 Input shaft gear
9 Intermediate shaft gear
10 Planet carrier 2
M44 1828
2 1
9
38 4 5
8
6
1
2
3 4
5
6
10
9
8
7
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-25
The planetary gear train used on the 5HP24 transmission comprises three planetary gearsets which together form a
compound gear train. The gearset operates in conjunction with the clutches, brakes and freewheel clutch to produce
five forward gears and one reverse gear.
Planetary Gearset – Exploded View
1 Ring gear 1
2 O-ring
3 Snap ring
4 Planetary gearset 1
5 Planetary gearset 2
6 Planetary gearset 3
7 Snap ring
8 Ring gear 3
9 Intermediate shaft gear
10 Ring gear 2
11 Input shaft gear
12 Needle roller bearing
13 Snap ring
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-26 DESCRIPTION AND OPERATION
The planetary gear train is a single integral assembly which comprises the following components:
l Three single planet carrier gearsets connected in series
l A single sun gear
l A twin sun gear
l Three ring gears.
Power Flows
Operation of the transmission is controlled by the EAT ECU which electrically activates various solenoids to control
the transmission gear selection. The sequence of solenoid activation is based on programmed information in the ECU
memory and physical transmission operating conditions such as vehicle speed, engine load, throttle position and
selector lever position.
Powerflow Schematic Diagram
1 Torque input from engine
2 Torque converter lock-up clutch
3 Transmission case
4 Planet gearset 1 carrier
5 Planet gearset 2 carrier
6 Input shaft sun gear – large
7 Planet gearset ring gear 1
8 Planet gearset 3 carrier
9 Planet gearset ring gear 3
10 Intermediate shaft sun gear
11 Input shaft sun gear – small
12 Planet gearset ring gear 2
13 Freewheel clutch
Gear Input Reaction Output Ratio
1st Planetary gearset 2 and 3 via
input shaft gear
Ring gear 1 and clutch 'F' Planetary gear 3 carrier 3.57
2nd Planetary gearset 2 and 3 via
input shaft gear
Planet gear 2 carrier and ring
gear 3
Planetary gear 3 carrier 2.20
3rd Ring gear 1 Planet gear 1 carrier and ring
gear 2
Planetary gear 3 carrier 1.51
4th Planetary gearset 2 and 3 via
input shaft gear and planet
gear 2 carrier
Ring gear 3 Planetary gear 3 carrier 1.00
5th Planetary gearset 2 carrier Ring gears 1 and 3, Planetary
gear 2 carrier and input shaft
gear
Planetary gearset 3 carrier 0.80
Reverse Intermediate shaft gear Ring gear 2, planetary
gearset 2 carrier and input
shaft gear
Planetary gearset 3 carrier 4.10
M44 1829
2
1
10
A
B
C
DE
7
8
4
11
5
9
6
12
13
3
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-27
Engine torque is transferred, via operation of single or combinations of clutches, to the planetary gear train. The
planetary gear train is controlled by reactionary inputs from brake clutches and the freewheel clutch to produce five
forward gears and one reverse gear.
The following tables show which clutches are operating for selected gear ratios and which solenoids are activated to
produce the required torque output from the transmission.
Gear Range Reference Chart
Gear Change Solenoid Reference Chart
Gear
Selector
Lever
Position
Gear Engine
Braking
Yes/No
Ratio Clutches Freewheel
Locked Y/N
ABCDEF
D1Y3.57X Y
D2Y2.20X X
D3Y1.51X X
D4Y1.00XX
D5Y0.80 X X
P/N –– – X
R Y– 4.10 X X
Gear Selector
Lever Position
Gear Shift Control Solenoids Pressure Regulating Solenoids
SV1 SV2 SV3 EPRS1 EPRS2 EPRS3 EPRS4 EPRS5
D 1 ON OFF OFF ON ON – ON OFF ON –
D 2 ON ON OFF ON OFF ON OFF ON
D 3 OFF ON OFF ON ON ON OFF OFF
D 4 OFF ON OFF ON OFF OFF – ON – OFF
D 5 OFF OFF OFF ON ON OFF – ON – OFF
N ON OFF ON ON – ON ON OFF – ON
R OFF ON OFF ON ON – ON OFF ON –
TCC Lock-up OFF OFF OFF OFF OFF OFF ON OFF
ON = Active (pressure build up)
OFF = Inactive
– = Inactive (pressure drain)
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-28 DESCRIPTION AND OPERATION
1st Gear (D Selected)
The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is transmitted from
the torque converter to the planet gearset 3. The torque is applied to the input shaft gear via the application of clutch
'A'. The freewheel clutch locks the planet carrier of gearset 2 in the direction of rotation.
The larger diameter input shaft gear drives the planet gears of gearset 3, which rotate inside the locked ring gear 3.
This rotation is passed via the planet carrier of gearset 3 to the output shaft.
In 1st gear with braking effect when coasting, the brake clutch 'F' is also applied locking the ring gear 3 in both
directions.
M44 1938
WK
A
B
C
DE
F
M44 1944
F
A
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-29
2nd Gear (D Selected)
The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is transmitted from
the torque converter to the planet gearset 3. The torque is applied to the input shaft gear via the application of clutch
'A'.
The clutch 'E' is applied which locks the planet carrier of gearset 1. The planet carrier is physically connected to the
ring gear 2 which is subsequently also locked.
The small diameter input shaft gear drives the planet gears of gearset 2, which rotate around the stationary ring gear
2 in the direction of engine rotation. The planet carrier of gearset 2 is physically connected to the ring gear 3 which
subsequently rotates in the same direction. The rotation of the ring gear 3 is transmitted to the planet gearset 3, which
rotates around the large diameter gear of the input shaft gear. The rotation is passed via the planet carrier of gearset
3 to the output shaft which rotates at an increased speed compared to 1st gear.
M44 1939
WK
A
B
C
D E
F
M44 1945
E
A
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-30 DESCRIPTION AND OPERATION
3rd Gear (D Selected)
The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is transmitted from
the torque converter through the input shaft gear via the application of clutch 'A'. Clutch brake 'D' is applied and holds
the intermediate shaft gear stationary.
Ring gear 1 is driven by the planet gearsets 2 and 3. The torque applied to ring gear 1 is passed via the stationary
intermediate shaft gear to the planet carrier of gearset 1. The planet carrier of gearset 1 is physically connected to the
ring gear 2. This causes the planet carrier of gearset 2 to rotate at a higher speed. Because the planet carrier of
gearset 2 is physically connected to the ring gear 3, the ring gear 3 rotates in the same direction. This causes the ring
gear 3 and subsequently the planet carrier of gearset 3 and the output shaft to rotate at an increased speed compared
to 2nd gear.
M44 1940
WK
A
B
C
D E
F
M44 1946
C
A
D
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-31
4th Gear (D Selected)
The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is transmitted from
the torque converter to the input shaft gear via clutch 'A' and the planet carrier of gearset 2 via the clutch 'B'. The
planet carrier of gearset 2 is physically connected to the ring gear 3 and this drive is transmitted, via the ring gear 3
and the planet gears and carrier of gearset 3 to the output shaft, which rotates at an increased speed compared to
3rd gear.
The drive transmitted from the planet carrier of gearset 2 and the input shaft gear to planet gearset 3 results in a
complete locking of the planetary gear train. Therefore, in this condition the engine input speed is identical to the
output shaft speed creating a 1:1 output ratio.
M44 1941
WK
A
B
C
DE
F
M44 1947
B
A
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-32 DESCRIPTION AND OPERATION
5th Gear (D Selected)
The gear selector lever and the manual selector valve spool are in the 'D' position. Engine torque is transmitted from
the torque converter to the planet carrier of gearset 2 via the application of clutch 'B'. Clutch 'D' is applied to lock the
intermediate shaft gear.
The planet carrier of gear 2 is physically connected to the ring gears 1 and 3 and drives them at the same speed. The
rotation of ring gear 1 is passed to the planet gears of gearset 1 which rotate around the locked intermediate shaft
gear. The rotation of the planet gears is passed through the planet carrier of gearset 1 to the ring gear 2, to which it
is physically connected.
The rotation of the ring gear 2 is passed to the planet gears of gearset 2 which in turn rotates the small diameter gear
of the input shaft gear. This rotation is then passed, via the larger diameter gear of the input shaft gear, to the planet
gears of gearset 3 in the direction of engine rotation.
This rotation of the planet gears of gearset 3 increases the rotational speed of the planet carrier of gearset 3 and
subsequently drives the output shaft at an increased speed compared to 4th gear.
M44 1942
WK
A
B
C
D E
F
M44 1948
B
C
D
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-33
Reverse Gear (R Selected)
The gear selector lever and the manual selector valve spool are in the 'R' position. Engine torque is transmitted from
the torque converter to the intermediate shaft gear. The torque is applied to the intermediate shaft gear via the
application of clutch 'C'.
Clutch 'F' is applied and holds the ring gears 1 and 3 stationary and subsequently the planet carrier of gearset 2 which
is physically connected to ring gear 3.
The intermediate shaft gear drives the planet gears of gearset 1 which in turn rotate around the locked ring gear 1.
The rotation of the planet carrier of gearset 1 is transferred to the ring gear 2 to which it is physically connected. The
rotation of ring gear 2 is transferred to the planet gears of gearset 2. Because the planet carrier of gearset 2 is held
by clutch 'F', the drive is passed from the planet gears to the small gear on the input shaft gear.
The rotation is transferred via the large gear on the input shaft gear to the planet gears of gearset 3, which rotate
around the stationary ring gear 3. The rotation of the planet gears rotates the planet carrier of gearset 3 which in turn
rotates the output shaft in the reverse direction to that of the forward gears.
M44 1943
WK
A
B
C
DE
F
M44 1949
F
C
D
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-34 DESCRIPTION AND OPERATION
Sensors
The 5HP24 transmission contains two speed sensors and a temperature sensor. The sensors are located inside the
transmission housing, with the speed sensors being the only serviceable items.
The sensors play an important part in the operation of the transmission and provide signal information to the EAT
ECU. This information is used by the ECU to control shift timing and fluid temperature to provide the optimum
operating condition for the transmission.
Speed Sensors
Two speed sensors are used in the 5HP24 transmission to monitor turbine speed and output shaft speed.
The turbine speed sensor is monitored by the EAT ECU to calculate the slip of the torque converter clutch and internal
clutch slip. This allows the EAT ECU to accurately control the slip timing during shifts and adjust clutch application or
release pressure for overlap shift control.
The output shaft speed is monitored by the EAT ECU and compared to engine speed signals received on the CAN
from the ECM. Using the comparison of the two signals the EAT ECU calculates the transmission slip ratio for
plausibility and maintain adaptive pressure control.
The turbine speed sensor is located in the main casing and secured with a screw. The sensor monitors turbine speed
from a toothed target wheel which on the outer diameter of clutch 'B' housing.
The output shaft speed sensor is located at the rear of the main casing and secured with a screw. The sensor monitors
the output shaft speed from a toothed target wheel which is an integral part of the park lock gear.
Both sensors are of the inductive type and are connected to the EAT ECU with two wires. The EAT ECU supplies a
positive DC supply and a signal return wire to monitors the sensor signals. Both wires are covered by a screen which
is connected to ground by the EAT ECU.
The sensor receives the DC supply from the EAT ECU. As the teeth of the target wheel pass the sensor tip, a change
in the magnetic field of the sensor occurs and generates an AC pulse in the sensor field winding. The pulse is passed
on the negative (ground) wire to the EAT ECU which calculates the rotational speed. The AC pulse generated is
proportional to the rotational speed of the target wheel. The EAT ECU measures the peak to peak outputs of the AC
waveform to calculate the rotational speed being measured.
The resistance of the coil winding in each sensor is between 285 and 365Ω at 20°C (68°F). Failure of either speed
sensor will cause the EAT ECU to store a related fault code.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-35
Transmission Temperature Sensor
The temperature sensor is located inside the wiring harness in the fluid pan and is connected to the EAT ECU with
two wires. The sensor is a Positive Temperature Co-efficient (PTC) sensor which has a semi-conductor material which
increases its resistance as the temperature increases.
The sensor receives a predetermined current from the EAT ECU on one of the wires and is connected to earth via the
ECU on the second wire. The EAT ECU measures the returned voltage and using this information calculates the fluid
temperature.
In the case of low fluid temperatures, the EAT ECU prohibits torque converter lock-up to promote faster fluid warm
up. In the case of high fluid temperatures, the EAT ECU increases the converter lock-up control and modifies the shift
programme to reduce fluid temperature.
If the temperature sensor fails, the EAT ECU uses a programmed default temperature value. The default value is
derived from the engine coolant temperature sensor and received on the CAN from the ECM. A fault code is stored
in the ECM which can be retrieved using TestBook.
The temperature sensor has a semi-conductor material with resistance to temperature values as shown in the
following table.
Temperature Sensor Resistance Values
Temperature Resistance
0°C (32°F) 820 Ω
20°C (68°F) 962 Ω
40°C (104°F) 1118 Ω
60°C (140°F) 1289 Ω
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-36 DESCRIPTION AND OPERATION
Inhibitor Switch
The inhibitor switch is located externally on the right hand side of the transmission. The switch is located on the
selector shaft and secured to the main casing with screws. A protective cover is also fitted over the switch to prevent
impact damage. The switch rotates with the selector shaft, moving the switch contacts to correspond to the selected
programme. The switch provides signals which allows the EAT ECU to monitor the position of the manual selector
spool valve and the selected drive programme.
The switch is connected via an integral harness and multiplug on five wires to the EAT ECU. One of the wires supplies
a 12V supply to the switch. The remaining wires are connected to the EAT ECU. When the transmission selector lever
is moved to the selected position, one or more of the contacts within the switch are made, completing a circuit back
to the ECU. From the switch contacts which are made, the ECU determines which selection is required and responds
accordingly.
When the selector lever is in Park, the EAT ECU transmits a signal to the immobilisation ECU to enable starter
operation. The signal also energises the starter relay, allowing the crank signal from the immobilisation ECU to pass
to the starter solenoid.
The following table shows which switch contacts are made for a given selector lever position.
Selector Lever
Position
Switch Contacts
L1 L2 L3 L4
Park XXX
Reverse X X
Neutral X X X
Drive X
X = High signal
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-37
Fluid Cooling
1 Fluid feed
2 Fluid return
3 Fluid cooler
4 Engine coolant feed
5 Engine coolant return
The fluid cooler is located at the bottom right hand corner of the engine. The cooler is cooled by engine coolant which
flows in a water jacket around cores within the cooler body. Transmission fluid enters the cooler and flows through
the cores where it is cooled by the engine coolant. The fluid leaves the cooler and is passed back to the transmission.
The transmission fluid is pumped through the cooler by the transmission fluid pump.
The fluid cooler has a thermostatic valve which is opened by transmission fluid temperature. The thermostatic valve
is opened at a transmission fluid temperature of 80°C (176°F) and allows engine coolant to flow through the fluid
cooler.
2
M44 1839
3
2
1
1
5
3
4
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-38 DESCRIPTION AND OPERATION
Gear Selector Lever Assembly
1 Selector cable
2 Shift interlock solenoid
3 Selector lever
4 Manual +/– Steptronic switch
5 Selector knob and shroud
6 Park/Reverse release button
7 Selector lever cover
8 High/Low range selector switch
9 Selector position LED display
10 Hill Descent Control (HDC) switch
11 Key interlock cable
12 Key interlock mechanism
13 Selector lever position switch
14 Manual/Sport switch
15 Mounting plate
The gear selector lever assembly is located in a central position on the transmission tunnel, between the front driver
and passenger seats. A mounting plate is secured to the transmission tunnel and provides the mounting for the
selector lever assembly.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-39
The selector lever comprises a cast mounting plate which provides for the location of the selector components. The
lever is connected to a gimbal mechanism which allows for the selection of P, R, N, D is a forward or backward
direction and selection between automatic and manual/sport in a left/right transverse direction. When manual/sport
mode is selected, the lever can be moved in a forward or backward direction to select + or – for manual (Steptronic)
operation.
When the selector lever is moved to the M/S position, the Bowden cable to the transmission is mechanically
disconnected at the shifter. If left in Sport mode all gear changes are performed automatically. If Manual (Steptronic)
mode is selected, all gear changes are based on switched ground inputs received by the EAT ECU from the Manual
+/– Steptronic switch.
The selector lever mechanism houses the following components:
l Manual +/– Steptronic switch
l Shift interlock solenoid
l High/Low range selector switch
l Hill Descent Control (HDC) switch
l Selector position LED display
l Selector lever position switch
l Manual/Sport switch
l Key interlock mechanism.
There are four selector lever positions and two additional positions for manual/sport operation:
l P ( Park) – Prevents the vehicle from moving by locking the transmission
l R (Reverse) – Select only when the vehicle is stationary and the engine is at idle
l N (Neutral) – No torque transmitted to drive wheels
l D (Drive) – This position uses all five forward gears in high and low ranges
l M/S (Sport mode) – This position uses all five forward gears as in 'D', but will upshift at higher engine speeds
improving acceleration
l + and – (Manual 'Steptronic' mode) – Movement of the selector lever in the +/– positions, when the lever is in
the M/S position, will operate the transmission in manual (Steptronic) mode, allowing the driver to manually select
all five forward gears.
The selector lever position is displayed to the driver on the selector position LED display and in the instrument
pack. In 'Steptronic' mode, if a gear is selected but the EAT ECU logic prevents selection of that gear, the
requested gear will be initially displayed. The EAT ECU will engage the next allowed gear and then display that
gear.
Manual +/– Steptronic Switch
The manual +/– switch is located on the left hand side of the selector lever assembly. The switch comprises a housing
which provides the location for a sliding contact. When the selector lever is moved to the manual/sport position, a dog
on the lever engages with a slotted abutment on the switch sliding contact. When the lever is moved to the + or –
position the dog moves the switch completing a momentary earth circuit with one of two microswitches at each end
of the switch which correspond to the + or – positions.
This momentary signal is received by the EAT ECU which, on first operation of the switch, initiates manual mode and
operates the transmission in the selected gear.
In this position, a spring will move the selector lever to the centre position when released.
Shift Interlock Solenoid
The shift interlock solenoid is located at the front of the selector lever assembly. The selector lever is connected to a
locking plate which has two holes which correspond to the 'P' and 'N' positions. When the ignition is on or the engine
is running, the solenoid is energised by the EAT ECU when the selector lever is in the 'P' or 'N' positions. When
energised, the solenoid ejects a pin which engages in the locking plate preventing the lever from being moved.
When the footbrake is applied, a signal from a brake switch is passed to the EAT ECU which de-energises the
solenoid allowing the lever to be moved from the 'P' or 'N' position. This prevents the selector from being moved to
the 'D' or 'R' position unintentionally and the application of the brakes also prevents the vehicle 'creeping' when the
gear is engaged.
Movement of the selector lever from the 'P' or 'N' positions is also prevented if the EAT ECU senses that the engine
speed is above 2500 rev/min, even if the brake pedal is depressed.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-40 DESCRIPTION AND OPERATION
High/Low Range Selector Switch
The high/low range switch is located on the selector lever cover, on the right hand side of the selector lever. The switch
can be identified by the a high/low range legend graphic and the switch lever is coloured white. High or low range can
be selected using this switch providing the vehicle speed is within defined limits and the gear selector lever is in the
neutral position.
+ TRANSFER BOX, DESCRIPTION AND OPERATION, Description.
Hill Descent Control (HDC) Switch
The HDC switch is located on the selector lever cover, on the left hand side of the selector lever. The switch can be
identified by the HDC legend graphic and the switch lever is coloured yellow. Operation of the HDC switch it not
directly related to automatic transmission operation.
+ BRAKES, DESCRIPTION AND OPERATION, Foundation Brakes.
Selector Position LED Display
The selector position LED display is located on the selector lever cover, between the HDC and high/low range
switches. The display has a graphic which shows the lever positions P, R, N, D, M/S and +/–. The P, R, N, D and M/
S positions each have a small, red LED which illuminates when that position is selected. The +/– positions do not have
an LED.
The LED display is controlled by the selector lever position switch, with the two components connected via a five wire
ribbon cable. The LED display is powered from the Body Control Unit (BCU) and remains illuminated until the BCU is
in sleep mode. The LED display is active at all times when the ignition is on.
Selector Lever Position Switch
The selector lever position switch is located on the right hand side of the selector lever assembly. The switch has a
moving contact which is connected to the selector lever. As the lever is moved, the sliding contact moves in the switch
completing a circuit with four further contacts in the switch which represent the four lever positions; P, R, N and D.
The switch is connected to the selector position LED display via a ribbon cable and provides the power for the display
LED's. The switch receives its power supply from the BCU.
Manual/Sport Switch
The manual/sport switch is located at the rear of the selector lever assembly. The manual/sport switch is a cam
operated microswitch. A lever with a roller is attached to the switch body. When the selector lever is moved from the
automatic 'D' position to the manual/sport 'M/S' position, the roller contacts a cam on the selector lever which
depresses the switch lever and operates the switch. The switch contacts remain closed when the selector lever is in
the manual/sport position.
The operation of the switch completes an earth path which is sensed by the EAT ECU which switches the transmission
operation to sport when ’M/S’ is selected and deselects sport mode when ’D’ (automatic operation) is reselected. The
completed earth path is connected to the EAT ECU via the M/S LED on the selector lever display which is illuminated
by an output from the ECU when M/S is selected.
Selector Cable
The selector cable is a Bowden type cable that connects the selector lever to the manual selector spool valve. A ’C’
clip secures the outer cable to the selector lever assembly. The inner cable is secured to an arm which is connected
to the selector lever via a 'U' shaped bracket and pin.
The transmission end of the outer cable is secured to a bracket on the transmission by a clamp nut. The transmission
has an operating lever which is attached to and operates the manual selector control spool valve. The inner cable is
attached to the operating lever by a clamp bush and locknut. The clamp bush allows for the adjustment of the selector
cable.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-41
Key Interlock Mechanism
1 Ignition key
2 Ignition switch
3 Bowden cable
4 Latch gate
5 Selector lever assembly
The key interlock mechanism prevents the key from being removed from the ignition switch when the selector lever
is any position other than 'P' PARK. This prevents the vehicle being accidentally left in neutral which would cause the
vehicle to move if the handbrake was not applied.
The mechanical mechanism is operated by a Bowden cable which is attached between the selector lever assembly
and the ignition switch. When the ignition switch is turned to the on position, the switch rotates a lever which in turn
pulls the cable. This lifts a latch in the selector lever assembly which is engaged with the selector lever when in the
'P' position.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-42 DESCRIPTION AND OPERATION
Instrument Pack
1 Instrument pack
2 Transmission status display
3 Message centre
4 Malfunction Indicator Lamp (MIL)
The instrument pack is connected to the EAT ECU via the CAN. Transmission status is transmitted by the EAT ECU
and displayed to the driver on one of two displays in the instrument pack.
+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
Malfunction Indicator Lamp (MIL)
The MIL is located in the lower left hand corner of the instrument pack, below the fuel gauge. Transmission related
faults which may affect the vehicle emissions output will illuminate the MIL.
The MIL is illuminated by the ECM on receipt of a relevant fault message from the EAT ECU on the CAN. The nature
of the fault can be diagnosed using TestBook which reads fault codes stored in the ECU memory.
Transmission Status Display
The transmission status display is located on the right hand side of the instrument pack, below the tachometer. The
display shows the selector lever position and in the case of manual (Steptronic) mode, the selected gear. The selector
lever position and gear selected displays are illuminated in a green colour when active.
70
1/2
1/2
1
/1
1/1
MPH
MPH
10
90
50
50
30
30
110
130
150
M44 1910
4
3
2
1
Symbol Description
P Park selected
R Reverse selected
N Neutral selected
D Drive selected
1 1st gear selected (Manual mode)
2 2nd gear selected (Manual mode)
3 3rd gear selected (Manual mode)
4 4th gear selected (Manual mode)
5 5th gear selected (Manual mode)
Low range selected. Flashes when
changing from low to high range.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-43
Additionally, the display also shows a low range symbol when low range is selected on. The low range symbol is
illuminated in an amber colour when active. When the transfer box is changing from low to high range, the low range
symbol flashes until the range change is complete.
Message Centre Display
The message centre is located below the speedometer and the tachometer at the bottom of the instrument pack. The
message centre is a Liquid Crystal Display (LCD) to relay vehicle status information to the driver. The message centre
can display the following transmission related messages:
l SPORT MODE
l MANUAL MODE
l SELECT NEUTRAL
l TRANSMISS'N OVERHEAT
l TRANSMISS'N FAILSAFE PROG
l LOW RANGE
l HIGH RANGE
l SLOW DOWN.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-44 DESCRIPTION AND OPERATION
EAT ECU
1 EAT ECU
2 E-box
3 ECM
The EAT ECU is the controlling component of the transmission. The ECU software was designed in conjunction with
Land Rover, Bosch and ZF Getriebe GmbH.
The EAT ECU is located in the E-box, which is positioned forward of the RH suspension top mount. The ECU is
secured in a clip adjacent to the ECM. The ECU has a blue connector socket colour which assists identification.
The E-box has a temperature controlled environment which maintains the optimum temperature for ECU operation.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
The EAT ECU uses three harness connectors for all input and output information.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-45
Inputs and Outputs
The sensor signals allow the EAT ECU to monitor transmission operation. The ECU processes the incoming signals
and compares this with data stored in its memory. If the received signals are not within the stored values, the ECU
will make adjustments to the transmission operation using the solenoids to provide optimum driveability and
performance.
The sensor inputs provide the EAT ECU with a constant update of the operating condition of the transmission and the
engine. The ECU compares this input data with mapped information stored in its memory and will make any required
adjustments.
EAT ECU Harness Connector C0193 Pin Details
EAT ECU Harness Connector C0932 Pin Details
EAT ECU Harness Connector C1835 Pin Details
Pin No. Description Input/Output
1 Ground for shift interlock solenoid Input
2 Power supply for shift interlock solenoid Output
3 Park signal to steering lock ECU Output
4 to 8 Not used –
9 Range change request 1 Output
10 Range change request 2 Output
11 to 17 Not used –
18 High/Low range switch Input
19 Selector manual Steptronic switch UP Input
20 Selector manual Steptronic switch DOWN Input
21 to 52 Not used –
Pin No. Description Input/Output
1 and 2 Not used –
3 Diagnostic ISO 9141 K line bus Input/Output
4 Electronic ground –
5 Power ground –
6 Power ground –
7 Permanent battery power supply Input
8 Power supply from main relay Input
9 Power supply from main relay Input
Pin No. Description Input/Output
1 Ignition power supply Input
2 Output shaft speed sensor screen –
3 Output shaft speed sensor signal Input
4 Inhibitor switch contacts L4 Input
5 Input shaft speed sensor screen –
6 Ground for EPRS 5 Input
7 Ground for EPRS 4 Input
8 to 10 Not used –
11 Power supply for EPRS's Output
12 Temperature sensor supply Output
13 Output shaft speed sensor supply Output
14 Inhibitor switch contacts L3 Input
15 Not used –
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-46 DESCRIPTION AND OPERATION
Main Relay
The main relay is located inside the E-box and is identified by its blue colour. The relay is connected directly from the
battery via a 100 Amp remote fuse. The relay coil is controlled by the ECM which provides a ground for the coil when
the relay is energised.
When energised, the main relay supplies battery voltage, via fuse 1 in the engine compartment fusebox, to the EAT
ECU.
Diagnostics
The diagnostic socket is located in the fascia, in the driver's side stowage tray. The socket is secured in the fascia
panel and is protected by a hinged cover.
16 Ground for SV 3 Input
17 Ground for EPRS 3 Input
18 to 20 Not used –
21 Power supply for SV's Output
22 Temperature sensor signal Input
23 Input shaft speed sensor supply Output
24 Inhibitor switch contacts L2 Input
25 Not used –
26 Ground for SV 2 solenoid Input
27 Ground for EPRS 2 Input
28 Ground for EPRS 2 Input
29 and 30 Not used –
31 Ignition power supply to inhibitor switch Output
32 Not used –
33 Input shaft speed sensor signal Input
34 Inhibitor switch contacts L1 Input
35 Not used –
36 CAN bus high Input/Output
37 CAN bus low Input/Output
38 Ground for SV 1 Input
39 and 40 Not used –
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-47
Diagnostic Socket
1 Cover 2 Diagnostic socket
The diagnostic socket allows the exchange of information between the various ECU's on the bus systems and
TestBook/T4 or a diagnostic tool using Keyword 2000 protocol. The information is communicated to the socket via a
diagnostic ISO9141 K Line. This allows the retrieval of diagnostic information and programming of certain functions
using TestBook/T4 or a suitable diagnostic tool.
The EAT ECU uses a P code strategy which stores industry standard and Land Rover specific Diagnostic Trouble
Codes (DTC) relating to faults.
Transmission P Codes
P Code No. Component/Signal Fault Description
0702 EAT ECU internal error 4 (FET/FET 1) Open circuit, short circuit to ground or
battery
0705 Inhibitor switch (PRNDL input) Implausible
0710 Gearbox temperature sensor Implausible
0711 Gearbox temperature sensor Open circuit
0712 Gearbox temperature sensor Short circuit to ground
0713 Gearbox temperature sensor Short circuit to battery
0715 Input speed sensor Implausible
0716 Input speed sensor Value too large
0720 Output speed sensor Implausible
0721 Output speed sensor Implausible, value too large
0730 Gear ratio monitoring Implausible
0731 1st gear ratio Implausible
0732 2nd gear ratio Implausible
0733 3rd gear ratio Implausible
0734 4th gear ratio Implausible
0735 5th gear ratio Implausible
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-48 DESCRIPTION AND OPERATION
0740 Pressure regulator solenoid 4 Implausible
0741 Torque converter lock-up clutch
performance
Implausible
0743 Pressure regulator solenoid 4 Open circuit, or short circuit to battery or
ground
0745 Pressure regulator solenoid 1 Implausible
0748 Pressure regulator solenoid 1 Open circuit, or short circuit to battery or
ground
0750 Shift control solenoid 1 Implausible
0751 Shift control solenoid 1 Open circuit
0752 Shift control solenoid 1 Short circuit to ground
0753 Shift control solenoid 1 Short circuit to battery
0755 Shift control solenoid 2 Implausible
0756 Shift control solenoid 2 Open circuit
0757 Shift control solenoid 2 Short circuit to ground
0758 Shift control solenoid 2 Short circuit to battery
0760 Shift control solenoid 3 Implausible
0761 Shift control solenoid 3 Open circuit
0762 Shift control solenoid 3 Short circuit to ground
0763 Shift control solenoid 3 Short circuit to battery
0775 Pressure regulator solenoid 2 Implausible
0778 Pressure regulator solenoid 2 Open circuit, or short circuit to battery or
ground
0780 Shift control No shift change
0782 Shift from 2 to 3 Value too big, no change
0783 Shift from 3 to 4 Value too big, no change
0795 Pressure regulator solenoid 3 Implausible
0798 Pressure regulator solenoid 3 Open circuit, or short circuit to battery or
ground
1601 EAT ECU checksum Implausible
1602 EAT ECU programme sensing Implausible
1604 EAT ECU internal error 3 (watchdog) General error
1605 EAT ECU EEPROM General error
1710 Battery voltage Implausible, too low
1711 Battery voltage Implausible
1743 Pressure regulator solenoid 5 Open circuit, or short circuit to battery or
ground
1745 Pressure regulator solenoid 5 Implausible
1748 Pressure regulator solenoid sum current Implausible
1789 Steptronic Implausible
1825 Shift lock solenoid Open circuit, or short circuit to ground or
battery
1840 Observation CAN bus Implausible
1842 CAN version fault Implausible
1844 CAN bus link with ECM Timed out
1845 CAN traction control timeout Implausible
1885 CAN brake signal Implausible
1884 CAN throttle signal Implausible
P Code No. Component/Signal Fault Description
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-49
Controller Area Network (CAN)
The CAN is a high speed broadcast bus network connected between the following electronic units:
l EAT ECU
l ECM
l Transfer box ECU
l Air suspension ECU
l Instrument pack
l ABS ECU
l Steering angle ECU.
The CAN allows fast exchange of data between ECU's. The CAN comprises two wires which are identified as CAN
high (H) and CAN low (L). The two wires are coloured yellow/black (H) and yellow/brown (L) and are twisted together
to minimise electromagnetic interference (noise) produced by the CAN messages.
+ COMMUNICATION DATA BUSES, DESCRIPTION AND OPERATION, Description.
In the event of a CAN failure, the following symptoms may be observed:
l Transmission operates in default mode
l Torque converter lock-up control is disabled
l ECM to EAT ECU engine torque reduction message inoperative
l Gear position display in instrument pack inoperative.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-50 DESCRIPTION AND OPERATION
Operation
Driving Modes
There are a number of different driving modes of operation. Some can be selected by the driver and some are
automatically initiated by the EAT ECU during driving:
l Normal mode
l Sport mode
l Manual (Steptronic) mode
l Engine warm up mode
l Hill Descent Control (HDC) mode
l Cruise mode
l Hill mode
l Default (Limp home) mode
l Reverse lock-out mode
l Cooling strategy.
Normal Mode
Normal mode is automatically selected by the EAT ECU on power up. In this mode all automatic and adaptive modes
are active. Normal mode uses gear shift and lock-up maps to allow vehicle operation which is a compromise between
performance, fuel consumption and emissions. If the transmission is operated in sport or manual mode and the
selector lever is moved to the 'D' position, normal mode is automatically resumed.
Sport Mode
The sport mode operates in high range only and provides enhanced acceleration and responsiveness. In sport mode
the EAT ECU uses shift maps which allow the transmission to downshift more readily, hold gears for longer at higher
engine speeds, and limits the transmission to 4th gear.
Sport mode is selected by moving the selector lever to the left into the 'M/S' position. When the sport mode is first
selected, 'SPORT' is displayed in the message centre for 6 seconds and, if 5th gear is currently engaged, the EAT
ECU downshifts to 4th.
Manual (Steptronic) Mode
Manual mode allows the transmission to operate as a semi-automatic 'Steptronic' unit. The driver can change up and
down the five forward gears with the freedom of a manual transmission.
Shift maps are provided for manual mode to protect the engine at high engine speeds. The EAT ECU will automatically
change up to a higher gear ratio to prevent engine overspeed and change down to a lower gear ratio to avoid engine
labouring and stalling.
When kickdown is requested the EAT ECU downshifts at least 2 gears.
When the vehicle is stationary, to drive off the driver can select 1st gear in high range, or 1st, 2nd or 3rd gear in low
range. Any other gear selection will be rejected by the EAT ECU.
When driving off, upshifts can be pre-selected by making + selections with the selector lever for the number of upshifts
required. The EAT ECU then automatically performs a corresponding number of upshifts when the appropriate shift
points are reached. So, for example, when starting off in 1st gear, if three + selections are made in quick succession,
the EAT ECU will automatically change up through the box to 4th gear as the vehicle accelerates, without any further
selections being made.
In manual mode a low gear can be selected to provide engine braking for descending a slope without HDC or
continuous use of the brake pedal. The driver can prepare for the end of the descent by moving the selector lever to
D. The EAT ECU will maintain the low gear and only revert to automatic shift control when the throttle is opened and
vehicle speed increases.
AUTOMATIC TRANSMISSION – ZF 5HP24
DESCRIPTION AND OPERATION 44-2-51
Engine Warm-Up Mode
The EAT ECU monitors the output from the transmission fluid temperature sensor in the transmission and also
receives an ECT sensor signal from the ECM on the CAN. When the transmission fluid and/or the engine coolant
temperature is less than 60°C (140°F), the EAT ECU initiates the shift maps used in sport mode, when driving after
a cold start.
The sport mode shift points raise the engine speed. This, in turn, promotes faster transmission fluid warm-up and also
decreases the warm-up time for the catalytic converter to reach optimum temperature.
The warm-up mode is terminated if the vehicle speed exceeds 37 mph (60 km/h), the transmission fluid or the engine
coolant temperature exceeds 60°C (140°F) or a maximum time of 3 minutes is exceeded.
HDC Mode
The HDC mode assists the ABS ECU in controlling the downhill speed of the vehicle. When HDC is selected on, the
EAT ECU selects the most appropriate gear for the descent, to maximise engine braking.
Cruise Mode
When cruise control is activated, the EAT ECU receives a cruise active message on the CAN. The EAT ECU activates
a cruise control map which prevents locking and unlocking of the torque converter clutch and minimises up and down
shifts. If cruise control is operative and the vehicle speed increases due to coasting downhill, the ECM can request a
down shift via a CAN message if the vehicle speed exceeds the set cruise limit.
Hill Mode
Hill mode is initiated by the EAT ECU when high engine torque, high throttle angle and low engine speed is detected
via ECM signals on the CAN. The EAT ECU defines this combination of signals to determine when the vehicle is
travelling on a steep gradient.
In hill mode the EAT ECU adopts one of three shift maps which hold the transmission in low gears throughout the
ascent. The shift map chosen depends on the severity of the slope as determined from the engine signals.
Hill mode can also be initiated when the vehicle is at very high altitudes.
Default (Limp Home) Mode
If a transmission fault is detected by the EAT ECU, the ECU adopts a limp home mode strategy. 'TRANS. FAILSAFE'
is displayed in the message centre and, if the fault has an effect on engine emissions, the MIL will also be illuminated.
In default mode, P, R and N functions operate normally (if the fault allows these selections) and the EAT ECU locks
the transmission in 4th gear to allow the driver to take the vehicle to the nearest dealer. The torque converter lock-up
clutch is disabled and reverse lock-out will not function.
If the vehicle is topped and subsequently restarted in the default mode condition, the EAT ECU operates normally
until the fault which caused the condition is detected again.
Reverse Lock-Out Mode
When the vehicle is travelling forwards, selecting reverse could cause transmission damage. To protect against this,
reverse gear is prohibited if the vehicle is travelling forwards at a road speed above 5 mph (8 km/h).
Cooling Strategy
The purpose of the cooling strategy is to reduce engine and transmission temperatures during high load conditions,
when towing a trailer for example. Under these conditions the engine and transmission may generate excessive heat.
If the transmission fluid temperature increases to 140°C (284°F) or higher, the EAT ECU employs the cooling strategy.
The strategy uses a specific shift and torque converter lock-up clutch map. This map allows torque converter clutch
lock-up and gear shifts to operate outside of their normal operation. This will reduce the engine speed and/or slip in
the torque converter, therefore reducing heat generated by the engine and the transmission.
The cooling strategy is cancelled when the transmission fluid temperature decreases to 130°C (266°F) or below.
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-52 DESCRIPTION AND OPERATION
Transmission Fault Status
If the EAT ECU detects a fault with the transmission system, it will enter a default mode to prevent further damage to
the transmission and allow the vehicle to be driven.
When a fault is detected a CAN message is sent from the EAT ECU and is received by the instrument pack. The
instrument pack illuminates the MIL and displays 'TRANS. FAILSAFE' in the message centre.
Some transmission faults may not illuminate the MIL or display a fault message, but the driver may notice a reduction
in shift quality.
Engine Speed and Throttle Monitoring
The ECM constantly supplies the EAT ECU with information on engine speed and throttle angle through messages
on the CAN. The EAT ECU uses this information to calculate the correct and appropriate timing of shift changes.
If the messages are not received by the ECM, the EAT ECU will implement a back-up strategy to protect the
transmission from damage and allow the vehicle to be driven.
In the event of an engine speed signal failure, any of the following symptoms may be observed:
l Decrease in fuel economy
l Increase in engine emissions.
In the event of a throttle position signal failure, any of the following symptoms may be observed:
l Harsh shift changes
l No kickdown
l Torque reduction request inhibited.
DRIVE AND PROPELLER SHAFTS
DESCRIPTION AND OPERATION 47-1
DRIVE AND PROPELLER SHAFTSDESCRIPTI ON AND OPERATION
Drive and Propeller Shafts – Component
Location
V8 specification shown, Td6 specification similar
1 Front RH drive shaft
2 Mounting bracket
3 Engine sump
4 Transfer box
5 Rear propeller shaft assembly
6 Rear RH drive shaft
7 Rear differential
8 Rear LH drive shaft
9 Support bearing
10 Front propeller shaft
11 Front LH drive shaft
12 Front differential.
DRIVE AND PROPELLER SHAFTS
47-2 DESCRIPTION AND OPERATION
Description
General
The front drive shafts are handed components with the RH drive shaft being longer than the LH drive shaft. Both shafts
are of similar construction with constant velocity (CV) joints at each end to allow for steering and suspension
movement.
The rear drive shafts are identical with a CV joint at each end to allow for suspension movement.
Propeller shafts are used to transmit drive from the transfer box to the front and rear differentials.
The front propeller shaft is a one piece unit, connected to the transfer box by a flexible rubber coupling and mating
with the front differential unit via a splined shaft.
The rear propeller shaft is a two piece unit, supported on a central bearing due to its increased length. The propeller
shaft is connected to the transfer box and the rear differential with CV joints. A universal joint allows for the angular
deviations of the propeller shaft due to acceleration and braking.
Front Drive Shafts
The front drive shafts are similar in their construction. The only difference is the lengths of each shaft. The LH drive
shaft has a total length of 677 mm. The RH drive shaft is a longer shaft which passes through a housing and the engine
sump to the differential and has a total length of 1024 mm.
LH drive shaft shown, RH drive shaft similar
1 Snap ring (3 off)
2 Drive shaft
3 Outer CV joint
4 Stake nut
5 Inner CV joint.
DRIVE AND PROPELLER SHAFTS
DESCRIPTION AND OPERATION 47-3
The outer CV joint has a target on the outer diameter. This is used by the ABS wheel speed sensor for vehicle and
wheel speed calculations.
+ BRAKES, DESCRIPTION AND OPERATION, Foundation Brakes.
Each drive shaft comprises two CV joints and gaiters, an outer tube, a solid shaft and a ball cage assembly.
Front Drive Shaft – Sectional View
LH drive shaft shown, RH drive shaft similar
1 Outer CV joint
2 Clamp
3 Outer tube
4 Sealing plug
5 Ball cage
6 Shaft
7 Inner CV joint
8 Snap ring – differential
9 Snap ring
10 Gaiter
11 ABS sensor target ring.
The CV joints are of the Birfield design. This design uses longitudinal, elliptical grooves which retain six steel balls.
The balls are further retained by a cage. The constant velocity is achieved by the position of the steel balls. If a centre
line is drawn through the balls and the driven hub or differential shaft, the two centre lines always bisect each other
at the angle of drive. This condition allows the rotational speed of the driven shaft to be passed to the driven hub or
differential shaft with no loss of rotational speed regardless of the shaft angle. The CV joints are packed with grease
which is retained in the joint by a synthetic rubber gaiter. The gaiter is retained at each end by a metal clamp which
provides a water tight seal to prevent the ingress of dirt and moisture. The CV joints are retained on their respective
shaft or tube by an internal snap ring. The snap rings are located in a groove on each shaft or tube end and locate in
a mating groove in the CV joint. The CV joints can be removed by a sharp tap with a soft mallet on the CV joint housing
which releases the snap ring from the groove.
The shaft is a sliding fit inside the outer tube which allows for the small length changes which occur with articulation
of the suspension. The shaft is located in a ball cage which is retained inside the outer tube. The ball cage ensures
that the shaft is held rigidly in the outer tube whilst allowing it to freely move in and out of the tube as necessary. A
sealing plug is pressed into the outer tube and retains grease around the balls in the cage.
The inner CV joint shaft is splined and mates with splines in the front differential. A snap ring is located around the
inner shaft and, when fitted in the differential, locates in a mating groove in the differential splined bore. The CV joint
shaft is removed from the differential in a similar manner as removing a CV joint.
9
10
10
9
M47 0439
1
8
7
2
6
2
5
4
2
3
2
11
DRIVE AND PROPELLER SHAFTS
47-4 DESCRIPTION AND OPERATION
Rear Drive Shafts
1 Drive shaft
2 Outer CV joint
3 Stake nut
4 Snap ring (2 off)
5 Bolt M12 (6 off)
6 Shim (3 off)
7 Inner CV joint.
The rear drive shafts are identical in their construction. Each drive shaft has a total length of 687 mm. The inner CV
joint has six holes for attachment with bolts to the differential output flange. Each pair of bolts is fitted with shim which
secures the bolts after tightening.
The outer CV joint has a target on the outer diameter. This is used by the ABS wheel speed sensor for vehicle and
wheel speed calculations.
+ BRAKES, DESCRIPTION AND OPERATION, Foundation Brakes.
Each drive shaft comprises two CV joints and gaiters and a tubular shaft.
DRIVE AND PROPELLER SHAFTS
DESCRIPTION AND OPERATION 47-5
Rear Drive Shaft – Sectional View
1 End cap
2 Inner CV joint
3 Circlip
4 Gaiter
5 Tube
6 Outer CV joint
7 ABS Sensor target ring
8 Snap ring
9 Clamp
10 Circlip.
The CV joints used on the rear drive shafts are of the Birfield design. Refer to the Front Drive Shafts for a description
of the CV joints.
The outer CV joint is retained on the tube by an internal snap ring. The CV joint can be removed by a sharp tap with
a soft mallet on the CV joint housing which releases the snap ring from the groove. The inner CV joint is retained on
the shaft by two circlips. This CV joint is different in design to the outer CV joint but the operating principle is the same.
An end cap is pressed over the inner end of the CV joint to prevent the ingress of dirt and moisture. Both CV joints
are fitted with gaiters which are secured with metal clamps.
7
M47 0441
9
8
9
9
9
4
2
3
1
5
6
4
10
DRIVE AND PROPELLER SHAFTS
47-6 DESCRIPTION AND OPERATION
Front Propeller Shaft
1 Front propeller shaft
2 Nut M12 (6 off)
3 Coupling adaptor
4 Coupling
5 Bolt M12 (6 off)
6 Seal.
The front propeller shaft is constructed from 2.1 mm wall tubular steel. A three arm coupling is welded at one end.
The opposite end has a splined shaft welded to the tube. The shaft has an overall length of 752 mm.
The three arm coupling has three holes which allow for attachment to the coupling and the coupling adaptor. The
coupling adaptor and the coupling are secured to the shaft with three bolts and nuts. The flexible coupling attaches
to the front output shaft of the transfer box and is secured with bolts in the three remaining holes in the coupling.
The coupling is a rubber moulding. The coupling is designed to transfer rotational drive from the transfer box to the
front propeller shaft without wind-up, but simultaneously compensating for small amounts of misalignment and
absorbing torque and vibrational loading. Each of the six attachment holes is lined with a metal bush. The bush is
required to prevent compression of the coupling by the attachment bolts and nuts.
The splined shaft has 42 splines which mate with corresponding splines in the input shaft of the front differential. A
shroud is pressed over the splined shaft. The shroud seals against an O-ring seal on the front differential input shaft,
preventing the ingress of dirt and moisture. The splines allow for movement of the propeller shaft caused by small
movements in the transmission and transfer box mountings.
DRIVE AND PROPELLER SHAFTS
DESCRIPTION AND OPERATION 47-7
Rear Propeller Shaft
1 Washer
2 Bolt M12
3 Propeller shaft - Front
4 Stud (6 off)
5 Shim (3 off)
6 Nut (6 off)
7 Nut (2 off)
8 Shaft bearing assembly
9 Propeller shaft - Rear
10 Bolt M12 (6 off)
11 Shim (3 off).
The rear propeller shaft assembly comprises front and rear shaft assemblies and a centrally mounted shaft bearing.
The rear propeller shaft assembly has an overall length of 1280 mm.
DRIVE AND PROPELLER SHAFTS
47-8 DESCRIPTION AND OPERATION
Front Shaft Assembly
The front shaft assembly comprises a CV joint at the front and a splined shaft at the rear. The front shaft comprises
a tube with welded, splined shafts at each end.
The forward splined shaft accepts the CV joint which is secured with a circlip. The CV joint is packed with grease and
sealed on both sides with metal shrouds to prevent the ingress of dirt and moisture. The CV joint has six radial holes
which provide for the attachment to the transfer box rear output flange. The joint is secured to the output flange with
six bolts, which screw into threaded holes in the flange. Three shims are fitted under each pair of bolts. The shims
have tabs which are bent to secure the bolts. The CV joint is not a serviceable item and failure will require replacement
of the rear propshaft assembly. The rear splined shaft mates with splines in the rear shaft universal joint. A threaded
hole is provided in the splined shaft to secure the front and rear propeller shaft sections together. A machined surface
on the shaft accepts the shaft bearing, which is a press fit.
Shaft Bearing Assembly
The shaft bearing assembly comprises a pressed steel housing, a rubber bush and a ball bearing. The rubber bush
is bonded into the housing. An internal metal ring, bonded to the bush, allows for the bearing to be press fitted into it.
The rubber bush allows for small deviations in alignment and also absorbs vibrational forces. The shaft bearing
assembly is located on studs, which are integral with the body, and secured with flanged nuts.
Rear Shaft Assembly
The rear shaft assembly comprises a universal joint at the front and a CV joint at the rear. The rear shaft comprises
a tube with the welded universal joint at one end and a welded splined shaft at the opposite end.
The universal joint is welded to the rear shaft tube. The opposite end of the universal joint has a splined bore which
mates with the splined shaft on the rear of the front shaft assembly. A bolt and washer is fitted through the splined
bore and screws into the splined shaft on the front shaft assembly, securing the front and rear shaft assemblies
together.
The splined shaft accepts the CV joint which is secured with a circlip. The CV joint is packed with grease and sealed
on both sides with metal shrouds to prevent the ingress of dirt and moisture. The CV joint has six radial holes into
which, six knurled bolts are pressed. The knurled shanks of the bolts provide a secure mounting for each bolt,
preventing them from rotating. Three shims are fitted under each pair of bolts. The shims have tabs which are bent to
further secure the bolts. The CV joint is secured to the input shaft of the rear differential with six flanged nuts. The CV
joint is not a serviceable item and failure will require replacement of the rear propshaft assembly.
FINAL DRIVE
DESCRIPTION AND OPERATION 51-1
FINAL DRIVEDESCRIPTION AND OPERATION
Differentials – Component Location
1 Front RH drive shaft
2 Mounting bracket
3 Engine sump
4 Transfer box
5 Rear propeller shaft assembly
6 Rear RH drive shaft
7 Rear differential
8 Rear LH drive shaft
9 Front propeller shaft
10 Front LH drive shaft
11 Front differential.
FINAL DRIVE
51-2 DESCRIPTION AND OPERATION
Description
General
The front and rear differentials convert the "angle of drive" through 90° and distribute drive, via the drive shafts, to the
front and rear wheels.
The front and rear differentials have different output ratios for the V8 and Td6 variants and, although visually similar,
can be identified by part number.
The front differential is mounted on the LH side of the engine sump. The rear differential is mounted on the rear
subframe.
Front Differential
The front differential is mounted on the LH side of the vehicle sump. The sump has a cast tube through it, which allows
for the fitment of the RH drive shaft and separates the engine oil from the differential oil. The differential unit is secured
to the engine sump with 4 bolts. The bolts pass through lugs in the differential casing and are secured into threaded
holes in the sump. An O-ring seal is fitted to the casing and locates in the sump to provide a seal between the casing
and the sump.
The casing comprises two halves with machined mating faces. When assembled, the iron casing halves are sealed
with a thin film of Loctite 574 sealant and secured together with twelve bolts. The LH casing is the carrier for all the
rotating parts and the RH casing is a cover to close the unit and a support for the RH carrier bearing. A breather tube
is fitted to the casings. This allows a plastic tube to be fitted and routed to a high point in the engine compartment,
preventing the ingress of water when the vehicle is wading.
The LH casing is fitted with a drain plug and a filler/level plug. The level plug allows the unit to be filled with oil until it
leaks from the filler hole, ensuring the correct quantity of oil is added. The differential unit contains approximately 0.8
litre of oil for a dry fill and requires approximately 0.75 litre if oil is changed due to residual oil retained in the casings.
The differential is a conventional design using a hypoid gear layout. This employs a hypoid bevel pinion gear and
crown wheel, with the pinion offset below the centre line of the crown wheel. This design allows for a larger pinion
gear to be used which has the advantages of increased gear strength and reduced operating noise.
The front differential is available in two ratios. V8 engine vehicles use a differential with a final drive ratio of 3.73:1 and
Td6 engine vehicles use a final drive ratio of 4.10:1. The ratio is changed by changing the amount of teeth between
the crown wheel drive gear and pinion gear. Therefore for a ratio of 4.10:1, the crown wheel drive gear will have 4.10
times more teeth than the pinion gear. This equates to the crown wheel drive gear having 41 teeth and the pinion gear
having 10 teeth.
FINAL DRIVE
DESCRIPTION AND OPERATION 51-3
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FINAL DRIVE
51-4 DESCRIPTION AND OPERATION
Front Differential – Exploded View
FINAL DRIVE
DESCRIPTION AND OPERATION 51-5
1 O-ring seal
2 Bearing pre-load spacer
3 Bearing cup
4 Taper roller bearing
5 Casing screws (12 off)
6 Dowel (2 off)
7 RH Casing
8 Gasket
9 Crown wheel gear screws (10 off)
10 Carrier
11 Pinion gear and shaft assembly
12 Oil slinger
13 Taper roller bearing
14 Bearing cup
15 Oil baffle
16 Collapsable spacer
17 Bearing cup
18 Roller bearing
19 Oil seal
20 Deflector
21 Seal deflector
22 Input flange
23 O-ring seal
24 Pinion nut
25 Oil seal
26 Cap
27 Vent
28 LH Casing
29 Information label
30 Filler/Level plug
31 Drain plug
32 Crown wheel drive gear
33 Roll pin
34 Thrust washer
35 Dished plate
36 Sunwheel
37 Shaft
38 Planet gear
39 Thrust washer.
FINAL DRIVE
51-6 DESCRIPTION AND OPERATION
Front Differential – Sectional View
1 Crown wheel gear screw (10 off)
2 Planet gear
3 Taper roller bearing
4 Sun wheel (RH drive shaft output)
5 O-ring seal
6 Roll pin
7 RH casing
8 Input flange
9 Pinion nut
10 Oil seal
11 Taper roller bearing
12 Collapsable spacer
13 Taper roller bearing
14 Pinion gear
15 Planet gear
16 Oil seal
17 Taper roller bearing
18 Sun wheel (LH drive shaft output)
19 Shaft
20 Crown wheel drive gear
21 LH casing
22 Carrier
The differential comprises a pinion shaft and hypoid bevel gear, a crown wheel drive gear with an integral cage which
houses two planet gears. Two sun wheels are also located in the cage and pass the rotational drive to the drive shaft
shafts.
The pinion shaft is mounted on two opposed taper roller bearings with a collapsable spacer located between them.
The spacer is used to hold the bearings in alignment and also collapses under the pressure applied to the pinion nut.
This allows the nut to be tightened to a predetermined torque, which collapses the spacer, setting the correct bearing
preload.
The pinion shaft has an externally splined outer end which accepts and locates the input flange, which is retained by
the pinion nut. The opposite end of the output flange has an internal spline which provides positive location for the
front propeller shaft. The flange has an external O-ring seal which seals against the front propeller shaft shroud
preventing the ingress of dirt and moisture into the splines. An oil seal is pressed into the LH casing and seals the
input flange to the differential unit. The pinion shaft has a hypoid bevel gear at its inner end which mates with the crown
wheel drive gear.
The crown wheel drive gear is located on the carrier and secured with ten screws. The carrier is mounted on taper
roller bearings located in each casing half. The bearings are press fitted into the casing and a spacer is located on
the outside face to apply preload to the bearing.
M51 0149
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FINAL DRIVE
DESCRIPTION AND OPERATION 51-7
The carrier is fitted with a shaft onto which the two planet gears are mounted. The shaft is secured in the carrier with
a roll pin. The sun wheels are located in pockets within the carrier and mesh with the planet gears. Curved plates are
located between the carrier and the sun wheels and hold the sun wheels in mesh with the planet gears. Each sun
wheel has a machined, splined, bore to accept the drive shaft. A groove is machined in the bore to locate the snap
ring fitted to the drive shaft, providing positive drive shaft location.
Rear Differential
The rear differential is located centrally in the rear subframe. The front of the differential is attached to the subframe
via rubber bushes and bolts. The rear of the differential is mounted to the subframe via a single, offset rubber bush
and a bolt.
The casing comprises two parts. The pinion housing is made from cast iron and provides locations for all the internal
components. The pinion housing is sealed at the rear by an aluminium casting which is secured to the pinion housing
with eight bolts and spring washers. A gasket between the two casings seals the unit. The rear cover has cast fins
which assist heat dissipation. A breather tube is fitted to the rear cover. This allows a plastic tube to be fitted and
routed to a high point under the vehicle body, preventing the ingress of water when the vehicle is wading.
The rear cover contains an oil level plug which allows for oil filling and level checking, with the differential installed in
the vehicle. The level plug allows the unit to be filled with oil until it leaks from the filler hole, ensuring the correct
quantity of oil is added. The differential unit contains approximately 1.2 litres of oil from a dry fill. If oil is being replaced,
a smaller quantity of oil will be required due to residual oil retained in the pinion housing.
The differential is a conventional design using a hypoid gear layout, similar to the front differential. The rear differential
is available in two ratios. V8 engine vehicles use a differential with a final drive ratio of 3.73:1 and Td6 engine vehicles
use a final drive ratio of 4.10:1. The ratio is changed by changing the amount of teeth between the crown wheel drive
gear and pinion gear. Therefore for a ratio of 4.10:1, the crown wheel drive gear will have 4.10 times more teeth than
the pinion gear. This equates to the crown wheel drive gear having 41 teeth and the pinion gear having 10 teeth.
FINAL DRIVE
51-8 DESCRIPTION AND OPERATION
Rear Differential – Sectional View
1 Input flange
2 Bush mounting holes
3 Taper roller bearing
4 Collapsable spacer
5 Taper roller bearing
6 Snap ring
7 Oil seal
8 RH output flange
9 Taper roller bearing
10 Gasket
11 Sun wheel (RH drive shaft output)
12 Snap ring
13 Planet gear (2 off)
14 Shaft
15 Snap ring
16 Rear cover
17 Crown wheel gear bolt (10 off)
18 Rear cover bolt (8 off)
19 Sun wheel (LH drive shaft output)
20 Carrier
21 LH output flange
22 Oil seal
23 Taper roller bearing
24 Crown wheel drive gear
25 Pinion gear
26 Pinion housing
27 Pinion shaft
28 Oil seal
29 Nut retainer
30 Flanged nut.
M51 0150
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FINAL DRIVE
DESCRIPTION AND OPERATION 51-9
The differential comprises a pinion shaft and spiral bevel pinion gear and a crown wheel drive gear with an integral
cage which houses two planet gears. Two sun wheels are also located in the cage and pass the rotational drive to the
drive shafts.
The pinion shaft is mounted on two opposed taper roller bearings, with a collapsable spacer located between them.
The spacer is used to hold the bearings in alignment and also collapses under the pressure applied to the pinion
flanged nut. This allows the flanged nut to be tightened to a predetermined torque, which collapses the spacer, setting
the correct bearing preload.
The pinion shaft has an externally splined outer end which accepts and locates the input flange, which is retained by
the pinion nut. The output flange has six threaded holes and mates with the rear propeller shaft. Six bolts secure the
rear propeller shaft to the input flange. An oil seal is pressed into the pinion housing and seals the input flange to the
pinion housing. The pinion shaft has a spiral bevel gear at its inner end which mates with the crown wheel drive gear.
The crown wheel drive gear is located on the carrier and secured with ten screws. The carrier is mounted on taper
roller bearings located in machined bores on each side of the pinion housing. The bearings are retained in the casing
by a circlip, the thickness of which is selected to apply the correct bearing preload.
The carrier has a through hole which provides location for the shaft. The shaft provides the mounting for the planet
gears in the carrier cage. The shaft is fitted with a snap ring at one end which locates in a machined groove in the
carrier, locking the shaft in position.
The sun wheels are located in pockets in the carrier cage and mesh with the planet gears. Spacers are fitted between
the sun wheels and the carrier and set the correct mesh contact between the planet gears and the sun wheels. Each
sun wheel has a machined bore with internal splines and machined groove near the splined end. The groove provides
positive location for a snap ring fitted to the end of each output flange.
Each output flange has a splined shaft which located in each sun wheel. A snap ring fitted to the splined shaft locates
in the groove the sun wheel bore and positively located the output flange. Oil seals are pressed into each side of the
pinion housing and seal the output flange to the housing. Each output flange has six threaded holes which provide for
the attachment of the rear drive shafts.
The rear cover is located on the rear of the pinion housing and is sealed to the housing with a gasket and secured
with eight bolts.
FINAL DRIVE
51-10 DESCRIPTION AND OPERATION
Operation
Differential Operation
The operating principles of the front and rear differentials are the same. Rotational input from the propeller shaft is
passed via the input flange to the pinion shaft and pinion gear. The angles of the pinion gear to the crown wheel drive
gear moves the rotational direction through 90°.
The transferred rotational motion is now passed to the crown wheel drive gear, which in turn rotates the carrier. The
shaft, which is secured to the carrier also rotates at the same speed as the carrier. The planet gears, which are
mounted on the shaft, also rotate with the carrier. In turn, the planet gears transfer their rotational motion to the left
and right hand sun wheels, rotating the drive shafts.
When the vehicle is moving in a forward direction, the torque applied through the differential to each sun wheel is
equal. In this condition both drive shafts rotate at the same speed. The planet gears do not rotate and effectively lock
the sun wheels to the carrier.
If the vehicle is turning, the outer wheel will be forced to rotate faster than the inner wheel by having a greater distance
to travel. The differential senses the torque difference between the sun wheels. The planet gears rotate on their axes
to allow the outer wheel to rotate faster than the inner one.
STEERING
DESCRIPTION AND OPERATION 57-1
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STEERINGDESCRIPTION AND OPERATION
Steering Component Location – Td6
RHD shown, LHD similar
1 Fluid cooler
2 Servotronic valve
3 Lower column
4 Upper column
5 Steering wheel
6 Column adjustment motor – tilt
7 Column adjustment motor – reach
8 PAS pump
9 PAS fluid reservoir
10 Steering rack
11 LH track rod
12 RH track rod
M57 1177
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STEERING
57-2 DESCRIPTION AND OPERATION
Steering Component Location – V8
LHD shown, RHD similar
1 Fluid cooler
2 PAS fluid reservoir
3 Lower column
4 Upper column
5 Steering wheel
6 Column adjustment motor – tilt
7 Column adjustment motor – reach
8 Servotronic valve
9 LH track rod
10 PAS pump
11 Steering rack
12 RH track rod
M57 1178
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12
STEERING
DESCRIPTION AND OPERATION 57-3
Steering Control Diagram – Servotronic
A = Hardwired; B = K Bus; C = Diagnostic DS2 bus
1 Fuse 5A – Battery permanent supply
2 Servotronic valve
3 Body Control Unit (BCU)
4 ABS ECU
5 Instrument pack
6 Diagnostic socket
M57 1179A
1
A
2
3
4
5
6
B
C
STEERING
57-4 DESCRIPTION AND OPERATION
Steering Control Diagram – Column
Adjustment – Without Memory
A = Hardwired
1 Fuse (15A) – Permanent battery supply
2 Column adjustment motor – reach
3 Column adjustment motor – tilt
4 Column adjustment control unit
5 Steering column adjustment switch
STEERING
DESCRIPTION AND OPERATION 57-5
Steering Control Diagram – Column
Adjustment – With Memory
A = Hardwired
1 Fuse 30A – Permanent battery supply
2 Ignition switch
3 Seat relay
4 Fuse 30A – Seat power supply
5 Body Control Unit (BCU)
6 Column adjustment motor – reach
7 Column adjustment motor – tilt
8 Seat memory ECU
9 Steering column switch
STEERING
57-6 DESCRIPTION AND OPERATION
Steering Control Diagram – Column Lock
A = Hardwired; B = K Bus; C= Diagnostic DS2 bus
M57 1182B
1
A
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13
12
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2
4
5
6
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8
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B
10
STEERING
DESCRIPTION AND OPERATION 57-7
1 Fuse 30A – Permanent battery supply
2 Ignition switch
3 Instrument pack
4 Diagnostic socket
5 Body Control Unit (BCU)
6 Anti-lock Brake System (ABS) ECU
7 Electronic Automatic Transmission (EAT) ECU
8 Key in sensor
9 Immobilisation ECU
10 Steering lock ECU
11 Fuse 5A – Auxiliary supply
12 Fuse 5A – Ignition supply
13 Fuse 10A – Permanent battery supply
14 Fuse 50A – Permanent battery supply
STEERING
57-8 DESCRIPTION AND OPERATION
Steering Control Diagram – Steering
Wheel Heating
A = Hardwired
1 Fuse 30A – Permanent battery supply
2 Ignition switch
3 Steering wheel relay
4 Fuse 10A – Steering wheel heating ECU supply
5 Rotary coupler
6 Steering wheel heater element
7 Steering wheel heater thermostat
8 Steering wheel heating ECU
9 Steering wheel heater switch
STEERING
DESCRIPTION AND OPERATION 57-9
Description
General
Rack and pinion steering is introduced on Range Rover for the first time. A ZF power assisted steering rack is fitted
on the front subframe. The rack is a conventional end take-off rack and pinion power assisted unit with the addition
of ZF Servotronic 2 assistance.
Servotronic 2 adds electronic control and speed sensitive steering to the steering rack. The Servotronic 2 feature
provides easy and comfortable steering operation when parking, improved 'road feel' at increased road speeds and
adds an integrated, positive centre feel feature which optimises steering wheel torque during high speed driving.
The Servotronic 2 system is controlled by software which is incorporated into the Body Control Unit (BCU). The
software responds to steering torque inputs and road speed signals and controls the assistance via a transducer valve
located on the steering rack valve.
The steering column features fully electrical adjustment for tilt and reach. On vehicles fitted with memory seats, the
steering wheel position control is incorporated into the memory seat ECU.
The column also features an electronically controlled steering lock. The lock is operated when the ignition switch
senses that the correct key has been inserted. An ECU, located inside the steering column, controls a motor operated
lock, releasing the steering lock when appropriate.
STEERING
57-10 DESCRIPTION AND OPERATION
Steering Column
1 Bolt – Flanged
2 Steering wheel
3 Column adjustment motor – tilt
4 Column adjustment motor – reach
5 Steering angle sensor
6 Lower column – upper shaft
7 Lower column – lower shaft
8 Bulkhead mounting
9 Flexible coupling
10 Upper column – lower shaft
11 Upper column – upper shaft
12 Adjustable upper column
13 Lock housing/Tilt head
STEERING
DESCRIPTION AND OPERATION 57-11
The steering column comprises the upper column assembly which is connected to the steering rack via several shafts
which are connected via flexible couplings and universal joints.
The lower column comprises upper and lower shafts which are connected together as a sliding fit. The sliding fit allows
the shafts to collapse in the event of a frontal collision, preventing column intrusion into the vehicle interior. The upper
shaft is connected to a flexible coupling and provides the attachment to the upper column. The lower shaft has internal
splines which connect with splines on the steering rack valve input shaft.
The upper column also comprises two shafts which are also connected together as a sliding fit. The shafts are a
double 'D' section to prevent rotation. The sliding fit allows the shafts to collapse in the event of a frontal collision
further preventing intrusion into the vehicle interior. The lower shaft is connected to the flexible coupling which
transfers torque to the lower column and the steering rack. The upper shaft has a splined internal bore which connects
with the adjustable upper column assembly.
The upper column assembly comprises two extruded aluminium sections which connect together and can slide on
each other in the event of a frontal impact, further preventing column intrusion into the vehicle interior. The column is
attached to the cross-car tube with four bolts. A strap is bolted to the upper of the two aluminium sections. The strap
is coiled around a bush on the upper section and has a hook which locates on the lower section. In the event of a
frontal impact, the strap can unwind, allowing the upper column to collapse in a controlled manner absorbing energy.
The upper column also provides the location for the steering angle sensor which is used by the ABS system.
+ BRAKES, DESCRIPTION AND OPERATION, Foundation Brakes.
The upper column provides the locations for the column adjustment motors and the steering lock mechanism and
steering lock ECU. The steering lock operates via a locking bolt which engages with a locking sleeve located around
the column shaft. The locking sleeve has a tolerance ring which is located between the sleeve and the column. The
tolerance ring allows the locking sleeve to slip on the upper column shaft if a high torque is applied to the steering
wheel when the lock is engaged. This prevents the locking bolt from being sheared by someone forcibly turning the
steering wheel while the steering lock is engaged, yet still effectively locking the steering.
STEERING
57-12 DESCRIPTION AND OPERATION
Column Adjustment
1 Vertical adjustment cam
2 Adjustment motor – tilt
3 Worm drive – tilt adjustment motor
4 Worm drive – reach adjustment motor
5 Adjustment motor – reach
The steering column is adjusted using a four way switch located on the LH side of the steering column, below the LH
column control switch.
The steering column adjustment is achieved by two electric motors and a column adjustment control unit on vehicles
without memory seats or by the memory seat ECU on vehicles with memory seats. Both motors are attached to the
lock housing / tilt head assembly and move the column via worm drive screws.
The reach adjustment motor drives a screw shaft which moves the column in and out for reach adjustment. The
adjustment is achieved by the two extruded aluminium sections which slide on one another. The tilt adjustment motor
also drives a screw shaft. This shaft is connected to a cam, which causes the tilt head to pivot, adjusting the column
angle.
STEERING
DESCRIPTION AND OPERATION 57-13
On vehicles without memory seats, inputs from the column adjustment switch are received by the adjustment control
unit located under the column. The control unit interprets the signals from the switch and operates the requested
adjustment motor in the required direction.
On vehicles with memory seats, the adjustment control unit is not fitted. Inputs from the column adjustment switch are
received by the memory seat ECU which is incorporated into the driver's seat switch pack. The ECU interprets the
signals from the switch and operates the requested adjustment motor in the required direction. The motors used on
the memory vehicles have Hall effect sensors known as 'ripple counters'. These counters output the position of the
column when the seat memory store function is used and applies this setting to the applicable ignition key.
STEERING
57-14 DESCRIPTION AND OPERATION
Column Electronic Steering Lock
With the ignition switch located in the centre console, a conventional steering lock mechanism cannot be used. An
electronic system was designed which comprises an ignition switch assembly with a position switch and anti-rotational
lock and a steering column assembly locking unit with integrated steering lock ECU.
The upper steering column assembly houses the column lock mechanism and ECU. The components are assembled
with non-removable pins and is therefore non-serviceable. Failure of any steering lock components will require
replacement of the upper steering column assembly.
Steering Lock
1 Hall effect sensor targets
2 Locking motor
3 Safety release solenoid actuator
4 Spring
5 Locking bolt
6 Locking sleeve
7 Cam
8 Tolerance ring
STEERING
DESCRIPTION AND OPERATION 57-15
The steering column lock comprises a locking motor, locking bolt and a safety release solenoid actuator. The actuator
is required to hold the locking bolt in the unlocked position in the event of power loss during operation. The locking
motor drives a cam which moves the locking bolt into and out of engagement with the locking sleeve on the steering
column. The locking motor is fitted with a Hall effect sensor which informs the steering lock ECU of the position
(locked/unlocked) of the steering lock mechanism.
Steering Lock ECU Harness Connector
Steering Lock ECU Harness Connector C2055 Pin Details
Pin No. Description Input/Output
1 Ignition switch lock solenoid actuator Output
2 Ignition switch detection of rotation Input
3 Transmission selector lever Park/Neutral signal Input
4 Not used –
5 Transmission selector lever Park/Neutral signal Output
6 Ignition switch detection of rotation voltage Output
7 Battery power supply Input
8 K-bus Input/Output
9 Road speed Input
10 Ignition power supply Input
11 Auxiliary power supply Input
12 Ground –Input
M57 1198
C2055
STEERING
57-16 DESCRIPTION AND OPERATION
Ignition Switch and Locking Mechanism
1 Ignition switch contacts housing
2 Spacer
3 Key interlock mechanism
4 Ignition switch lock solenoid actuator
5 Hall sensor pick-up
6 Locking pin
7 Hall sensor target
8 Ignition key lock barrel
9 Key interlock cable connection point
10 Drive shaft and ignition switch lock cam
The ignition switch assembly also has a locking mechanism which works in conjunction with the immobilisation ECU
and the steering lock ECU. The ignition switch mechanism comprises an ignition switch lock solenoid actuator which
prevents the ignition switch being rotated unless the key has been recognised by the immobilisation ECU. A Hall
sensor is located in the ignition switch body and senses the rotation of the ignition switch. This signal is transmitted
on the K bus and is used by the steering lock ECU to confirm the key status with the immobilisation ECU. Refer to
Operation later in this section for functional description.
STEERING
DESCRIPTION AND OPERATION 57-17
Ignition Switch Lock Harness Connector
Ignition Switch Lock Harness Connector C0672 Pin Details
Pin No. Description Input/Output
1 Ignition switch detection of rotation Output
2 Ignition switch detection of rotation voltage Input
3 Ignition switch lock solenoid actuator Input
4Ground –
M57 1199
C0672
STEERING
57-18 DESCRIPTION AND OPERATION
Steering Rack
1 Banjo bolt (4 off)
2 Seal (8 off)
3 Pipe
4 Pipe
5 Steering rack
6 Locknut
7 LH track rod
8 Spacer
9 Nut
10 Inner track rod joint
11 Clamp (2 off)
12 Gaiter (2 off)
13 Seal (2 off)
14 Clamp (2 off)
15 Torx bolt M12 (2 off) – rack to subframe
mounting
16 Nut M12 (2 off) – rack to subframe mounting
17 RH track rod
18 Locknut M16
STEERING
DESCRIPTION AND OPERATION 57-19
The steering gear comprises the mechanical steering rack, the valve and an integrated hydraulic power cylinder.
The steering rack uses a rack with an integrated piston which is guided on plain bearings within the rack housing. The
pinion, which is attached to the valve runs in bearings and meshes with the rack teeth. The rack is pressed against
the pinion by a spring loaded yoke which ensures that the teeth mesh without any play. The pinion is connected to
the valve rotor via a torsion bar.
The rotary motion of the steering wheel is converted into axial movement of the rack by the pinion and is initiated by
the valve. This motion is transferred into movement of the wheels by adjustable track rod arms.
The rotary valve is used to control the pressurised fluid required for power assistance. The valve comprises a valve
body, a control bush and a torsion bar. The valve body has eight control groove in its bore. The control bush also has
eight radial grooves which are matched to the valve. The control bush is positively attached to the pinion. The torsion
bar is the connecting element between the valve body, the pinion and the control bush.
Torque input from the steering wheel is passed to the valve body and causes a rotary motion of the torsion bar. The
valve body changes its relative position to the control bush and subsequently the relative positions of the control
grooves is also changed. This allows pressurised fluid to pass via the mismatched grooves to the rack piston and
provide the required assistance in the selected direction.
The piston is located at one end of the rack housing. Each side of the piston is connected to fluid pressure or fluid
return via a metal external pipe which is connected to the valve housing.
Each end of the rack has a threaded hole which provides for the fitment of an inner track rod joint. The external ends
of the rack are sealed with gaiters which prevent the ingress of dirt and moisture. The inner track rod joints has a long
outer threaded shank which screws into the outer track rod. The steering toe can be adjusted using the threaded end
of the inner track rod. When the correct toe is achieved, a locknut on the inner tie rod is tightened to prevent further
inadvertent movement.
Servotronic Transducer Valve
The Servotronic transducer valve is located in a port on the side of the steering rack valve housing. The valve is sealed
in the housing with an O-ring seal and is secured with two long screws into threaded holes in the housing.
The Servotronic valve is a transducer controlled valve which responds to control signals supplied from the Body
Control Unit (BCU). The BCU contains a microprocessor which receives road speed signals from the ABS ECU and
calculates the correct controlling signal for the Servotronic valve. The Servotronic software within the BCU has a
diagnostic capability which allows TestBook/T4 to check the tune of the steering.
The Servotronic valve determines the hydraulic reaction at the steering rack rotary valve and controls the input torque
required to turn the steering wheel. The Servotronic system allows the steering to be turned with minimum effort when
the vehicle is stationary or manoeuvred at slow speed. The hydraulic reaction changes proportional to the vehicle
speed, with the required steering effort increasing as the vehicle moves faster. At high speeds, the Servotronic system
provides the driver with a good feedback through the steering providing precise steering and improved stability.
A major advantage of the Servotronic system is that fluid pressure and flow through the rotary valve remains constant
and allows full steering pressure to be available in an emergency where a sudden and unexpected steering correction
may be required.
Power Assisted Steering (PAS) Pump and Reservoir
The PAS fluid pumps used on both the Td6 and V8 models are of the vane type and are similar in their operation. The
pumps are driven by a polyvee belt from the engine crankshaft pulley. A tensioner is used to maintain the correct
tension on the belt.
STEERING
57-20 DESCRIPTION AND OPERATION
V8 PAS Pump and Reservoir
1 Cap
2 Reservoir
3 Reservoir mounting bracket
4 Engine mounting bracket
5 Pump assembly
6 Pulley
7 Screw M8 (2 off)
8 Bolt M6 (2 off)
9 Bracket
The V8 PAS pump comprises a body which houses the internal components of the pump. A pressure relief valve,
which also incorporates a flow control valve, is installed in the housing. The pressure relief valve limits the maximum
pressure to between 124 and 132 bar (1800 and 1915 lbf/in
2
). The flow control valve limits the maximum flow to
between 9.75 and 11.25 l/min (2.14 and 2.47 UK gal/min).
A shaft runs longitudinally through the pump. One end of the shaft has a drive flange which accepts the drive pulley.
The opposite end is closed by a cover. The shaft runs in bearings located in the body. Oil seals at each end of the
shaft prevent leakage.
An oval cam ring is located in the body. Ten vanes are housed in a carrier and rotate within the cam ring. The carrier
is mounted in the centre of the shaft and receives positive drive from the shaft via a drive pin. The carrier is seated
against an end plate which is located in the cover. The front of the carrier is covered by a port plate which is located
against a seal plate in the body. The port plate controls the fluid flow into and out of the vanes during their cycle.
The fluid reservoir used on the V8 model is mounted remotely on the LH side of the engine compartment, adjacent to
the engine coolant reservoir.
STEERING
DESCRIPTION AND OPERATION 57-21
Td6 PAS Pump and Reservoir
1 Cap
2 Reservoir
3 Rear engine mounting bracket
4 Pump assembly
5 Pulley
6 Front engine mounting bracket
The Td6 PAS pump comprises a body which houses the internal components of the pump. A pressure relief valve,
which also incorporates a flow control valve, is installed in the housing. The pressure relief valve limits the maximum
pressure to between 120 and 127 bar (1740 and 1840 lbf/in
2
). The flow control valve limits the maximum flow to
between 9.75 and 11.25 l/min (2.14 and 2.47 UK gal/min).
A shaft runs longitudinally through the pump. One end of the shaft has a drive flange which accepts the drive pulley.
The opposite end is closed by a cover. The shaft runs in bearings located in the body. Oil seals at each end of the
shaft prevent leakage.
An oval cam ring is located in the body. Ten vanes are housed in a carrier and rotate within the cam ring. The carrier
is mounted in the centre of the shaft and receives positive drive from the shaft via a drive pin. The carrier is seated
against an end plate which is located in the cover. The front of the carrier is covered by a port plate which is located
against a seal plate in the body. The port plate controls the fluid flow into and out of the vanes during their cycle.
The fluid reservoir used on the Td6 model is mounted integral with the pump. The fluid supply to the pump is direct
from a connection to the housing and the return is via a hose connection.
STEERING
57-22 DESCRIPTION AND OPERATION
Operation
Hydraulic Circuit Operation
The following hydraulic circuits show power steering operation and fluid flow for the steering in a straight ahead,
neutral position and when turning right. The circuit diagram for turning left is similar to that shown for turning right.
Steering in Neutral Position
Circuit shows steering rotary valve in neutral position with the vehicle not moving.
1 Return fluid control groove
2 Radial groove
3 Feed fluid control groove
4 Radial groove
5 Axial groove
6 Feed fluid control edge
7 Feed fluid radial groove
8 Return fluid control edge
9 Return fluid chamber
10 Cut-off valve
11 Radial groove
12 Servotronic transducer
13 Feed fluid radial groove
14 Radial groove
15 Orifice
16 Balls
17 Compression spring
18 PAS fluid reservoir
19 Torsion bar
20 Valve rotor
21 Reaction piston
22 Reaction chamber
23 Centering piece
24 Pressure relief/flow limiting valve
25 PAS pump
26 Inner track rod
27 Pinion
28 Valve sleeve
29 Steering rack
30 Rack housing
31 Power assist cylinder – right
32 Piston
33 Power assist cylinder – left
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STEERING
DESCRIPTION AND OPERATION 57-23
When the engine is started, the PAS pump draws fluid from the reservoir down the low pressure suction line. The fluid
passes through the pump and is delivered, via a hose, to the steering rack valve unit.
The pressurised fluid flows through a connecting bore in the valve and, via the feed fluid radial groove and the
transverse bores in the valve sleeve, passes to the feed fluid control groove of the valve rotor.
In the neutral (straight ahead) position , the fluid passes over the open feed fluid control edges to all valve sleeve axial
grooves. The fluid then passes through the open return fluid control edges and the return fluid control grooves of the
valve rotor. The fluid then passes via connecting bores to the return fluid chamber and to the reservoir via an external
hose.
Simultaneously, the radial grooves of the valve body and their associated pipes provide a connection between the left
and right power assist cylinders.
STEERING
57-24 DESCRIPTION AND OPERATION
Steering in Right Turn Position
Circuit shows steering rotary valve in right turn position, at high vehicle speed and with rapid steering corrections. The
Servotronic transducer valve is fully open and the maximum hydraulic reaction is limited by the cut-off valve.
1 Return fluid control groove
2 Radial groove
3 Feed fluid control groove
4 Radial groove
5 Axial groove
6 Feed fluid control edge
7 Feed fluid radial groove
8 Return fluid control edge
9 Return fluid chamber
10 Cut-off valve
11 Radial groove
12 Servotronic transducer
13 Feed fluid radial groove
14 Radial groove
15 Orifice
16 Balls
17 Compression spring
18 PAS fluid reservoir
19 Torsion bar
20 Valve rotor
21 Reaction piston
22 Reaction chamber
23 Centering piece
24 Pressure relief/flow limiting valve
25 PAS pump
26 Inner track rod
27 Pinion
28 Valve sleeve
29 Steering rack
30 Rack housing
31 Power assist cylinder – right
32 Piston
33 Power assist cylinder – left
When the steering wheel is turned to the right, the steering rack and piston moves to the left in the piston bore. The
valve rotor is rotated to the right (clockwise) and pressurised fluid is directed over the further opened feed fluid control
edges and to the associated axial grooves, the radial groove and via an external pipe to the left power assist cylinder
chamber. The pressure applied to the piston from the left power assist cylinder chamber provides the hydraulic
assistance.
An adaptable pressure build-up is achieved by the partially or fully closed feed fluid control edges restricting or
preventing a connection between the fluid pressure inlet and the other axial grooves connected to the radial groove.
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STEERING
DESCRIPTION AND OPERATION 57-25
Simultaneously, the fluid pressure outlet to the pressurised axial grooves are restricted or partially restricted by the
closing return fluid control edges. The fluid displaced by the piston from the right power assist cylinder chamber, flows
through an external pipe to the radial grooves. From there the fluid passes to the associated axial grooves and on to
the return fluid control grooves, via the further opened return fluid control edges. The return flow of fluid to the reservoir
passes via interconnecting bores which lead to the return fluid chamber.
When the steering wheel is turned to the left the operating sequence is as above but the pressure is applied to the
opposite side of the piston.
Servotronic Operation
When the vehicle is manoeuvred into and out of a parking space (or other similar manoeuvre), the Servotronic function
of the BCU uses road speed data from the ABS ECU to determine the vehicle speed, which in this case will be slow
or stationary. The BCU microprocessor analyses the signals and outputs an appropriate control current to the
Servotronic transducer valve. The Servotronic valve closes and prevents fluid flowing from the feed fluid radial groove
to the reaction chamber. An orifice also ensures that there is return pressure in the reaction chamber. This condition
eliminates any 'reaction' ensuring that the steering is very light to operate, reducing the effort required to turn the
steering wheel.
As the vehicle is driven and the road speed increases, the BCU microprocessor analyses the road speed signals from
the ABS ECU and reduces the amount of control current supplied to the Servotronic valve. The Servotronic valve
reacts to the control current and opens the valve by an amount appropriate to the road speed. This allows a controlled
fluid supply from the feed fluid radial groove to the reaction chamber. The orifice prevents the loss of large amounts
of fluid to the return fluid chamber. The higher fluid pressure acting on the reaction piston causes compression of the
balls which are located between the reaction piston and the centering piece which in turn is securely connected to the
valve sleeve. When driving in a straight line, this has a positive effect on the exact centralising of the steering valve.
When the steering valve is actuated, the balls, with a higher load on them, provide additional torsional resistance to
rotation of the valve rotor. This mode of Servotronic assistance requires an established higher steering wheel torque
until the hydraulic assistance required in the left or right power assist cylinder is determined.
At high driving speeds, i.e. on a motorway, the Servotronic valve is fully open due to a very low or nonexistent control
current supplied from the BCU. This enables maximum pressure supply from the feed fluid radial groove to the
reaction piston. When the steering wheel is turned, the reaction pressure increases appropriate to the existing
operating pressure and pressurises the piston in the reaction chamber. As soon as the reaction pressure reaches its
upper limit, the fluid is discharged to the return fluid chamber via the cut-off valve and prevents further increases in
reaction pressure. This maintains the input torque applied through the steering wheel and provides the driver with an
improved 'road feel' allowing precise steering and directional stability.
Steering Lock ECU Operation
The steering lock ECU operates in conjunction with the immobilisation ECU and the ignition switch.
Detection of Unlock Request
When a 'valid' key is inserted in the ignition switch, the immobilisation ECU transmits a 'valid key in lock' message on
the K Bus. The steering lock ECU receives this message and starts the unlocking process of operating the steering
lock motor to disengage the locking bolt.
The immobilisation ECU goes into sleep mode 60 seconds after the vehicle is unlocked and a key is not inserted in
the ignition switch. When the key is subsequently inserted in the ignition switch and rotated, the rotation is sensed by
the Hall rotation sensor in the switch. Further rotation is prevented by the ignition switch lock solenoid actuator. The
rotation sensor transmits a signal which is received by the steering lock ECU. This ECU sends a 'request
immobilisation ECU status' message on the K bus which wakes the immobilisation ECU. When the immobilisation
ECU confirms that a valid key is inserted, the ignition switch lock disengages and the steering lock ECU starts the
unlocking process.
If the K bus is inoperative, the unlocking operation is initiated by the rotation sensor signal. This is indicated to the
driver through a delayed operation of the solenoid actuator preventing the key from being turned initially. The solenoid
actuator is operated on a delay which will initially prevent the key from being turned. The solenoid actuator will unlock
and allow the key to turn on the second attempt. A defect in the K bus is detected if no response from the
immobilisation ECU is received after a 2.4 seconds period after the 'request immobilisation ECU status' is sent.
STEERING
57-26 DESCRIPTION AND OPERATION
Unlocking of Steering Lock
If the battery voltage is 9V or less, the steering lock will be inoperative.
When a valid key is inserted and confirmed, the steering lock ECU activates the steering lock motor in the unlock
direction. Movement from the locked to the unlocked position is detected by the Hall sensor in the motor and sensed
by the steering lock ECU.
When the Hall sensor detects that the unlocked position has been reached, the ECU brakes the motor. The safety
release solenoid actuator is de-energised and its spring loaded pin drops into a recess in the locking bolt. This forms
a mechanical lock securing the locking bolt in the unlocked position preventing the steering lock from being applied
when the vehicle is being operated. A Hall sensor in the safety release solenoid actuator informs the steering lock
ECU of this condition. Once the unlocking procedure is successfully performed, the steering lock ECU de-energises
the steering lock motor.
Once the steering is successfully unlocked, the ignition switch lock disengages allowing the key to be turned to
positions II and III.
Detection of Locking Request
When the ignition key is turned to position 0, the ignition switch lock solenoid actuator remains active (unlocked) for
16 minutes. This function allows immediate restarting of the vehicle as long as the key is not removed from the ignition
switch. When the key is removed, the immobilisation ECU senses the removal and transmits a 'no valid key in lock'
message on the K bus. The steering lock ECU checks that the ignition switch position II or III outputs and the rotation
sensor are not active and initiates the steering locking process. This check ensures that the steering is not locked
when the vehicle may be being driven.
If the K bus is inoperative, locking of the steering column is prevented by the steering lock ECU. This is indicated to
the driver when attempting to start the vehicle through a delayed operation of the ignition switch lock solenoid actuator
preventing the key from being turned initially. The solenoid actuator is operated on a delay which will initially prevent
the key from being turned. The solenoid actuator will unlock and allow the key to turn on the second attempt. A defect
in the K bus is detected if no response from the immobilisation ECU is received after a 2.4 seconds period after the
'request immobilisation ECU status' is sent.
Locking of Steering Lock
The battery voltage must be greater than 10V and the vehicle must be stationary.
The ABS ECU transmits vehicle speed on a hardwired connection with the steering lock ECU. The steering lock ECU
uses the signal to determine when the vehicle has stopped.
When the key is removed and the steering lock ECU receives the 'no valid key in lock' message from the
immobilisation ECU, the steering lock motor is activated. The safety release solenoid actuator in the steering column
is energised, withdrawing the pin from the locking bolt. The Hall sensor in the solenoid actuator informs the steering
lock ECU that the lock is released.
The steering lock ECU then operates the steering lock motor in the lock direction. Movement from the unlocked to the
locked position is detected by the Hall sensor in the motor and sensed by the steering lock ECU. The safety release
solenoid actuator is de-energised and rests on the locking bolt.
SUSPENSION
DESCRIPTION AND OPERATION 60-1
SUSPENSIONDESCRIPTION AND OPERATION
Suspension Component Location
1 Front RH height sensor
2 Front RH strut assembly
3 Air suspension control switch
4 Reservoir and valve block
5 Rear RH damper
6 Rear RH air spring
7 Rear cross link valve
8 External pressure relief valve (where fitted)
9 Compressor assembly
10 Rear LH air spring
11 Rear LH damper
12 Rear LH height sensor
13 Rear RH height sensor
14 Air suspension ECU
15 Front LH strut assembly
16 Front LH height sensor
17 Front cross link valve
SUSPENSION
60-2 DESCRIPTION AND OPERATION
Suspension Control Diagram
A = Hardwired connections; B = K bus; C = Diagnostic DS2 bus; D = CAN bus
1 Fuse 15A – Permanent feed
2 Fusible link 100A
3 Fuse 50A
4 Air suspension relay
5 Compressor and motor
6 Temperature sensor
7 HP exhaust valve
8 Exhaust valve
9 Control switch
10 Body control Unit (BCU)
11 Air suspension ECU
12 Driver door module (Access mode switch)
13 Reservoir pressure sensor
14 Valve block
15 Front cross link valve
16 Rear cross link valve
17 LH rear height sensor
18 RH rear height sensor
19 LH front height sensor
20 RH front height sensor
21 ABS ECU
22 Instrument pack
23 Diagnostic socket
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SUSPENSION
DESCRIPTION AND OPERATION 60-3
Description
General
The main function of the four corner air suspension system is to maintain the vehicle at the correct ride height,
irrespective of load. Additionally, the system allows the driver to request ride height changes to improve off-road
performance or ease of access or loading. The system automatically adjusts the ride height to improve the vehicle
handling and dynamics when speed increases or decreases.
The system will temporarily inhibit height adjustments when the vehicle is subject to cornering, heavy acceleration or
heavy braking. The inhibit function prevents unsettling of the vehicle by reducing the effective spring rates.
Height changes are also inhibited for safety reasons, when a door is opened and the vehicle is stationary for example.
The air suspension system fitted to Range Rover is controlled by an ECU located behind the passenger side of the
fascia. The ECU monitors the height of each corner of the vehicle via four height sensors, which are mounted in-board
of each road wheel. The ECU also performs an 'on-board diagnostic' function to perform 'health checks' on the
system. If faults are detected, codes are stored in the ECU and can be retrieved using TestBook/T4.
The independent front and rear suspension offers many design and performance advantages over the conventional
beam axle design.
Front Suspension
The independent front suspension offers a reduction of un-sprung mass over the conventional beam axle design. The
suspension geometry features positive ground level off-set for improved control under braking. The suspension arms
have been designed for maximum ground clearance. Suspension geometry can be adjusted via the strut top mount
for camber and on the steering rack track rod ends for toe-in.
Front suspension features a 6mm positive off-set.
The following wheel travels are shown for on road and off-road vehicle operation. The difference between the two
operating conditions is a result of operation of the front cross-link valve. When the cross-link valve is opened the
suspension travel is as given for off-road wheel travel. When the cross-link valve is closed the suspension travel given
for on road applies.
The off road mode wheel travel is:
l 175 mm bump
l 95 mm rebound
l This gives a total of 270 mm off road suspension travel.
The on road standard wheel travel is:
l 115 mm bump
l 155 mm rebound
l This gives a total of 270 mm on road suspension travel.
The front suspension comprises:
l Two air spring damping struts
l Subframe
l Anti-roll bar
l Anti-roll bar links
l Suspension arms
l Two hub assemblies.
SUSPENSION
60-4 DESCRIPTION AND OPERATION
Front Suspension Components
1 RH front strut assembly
2 RH compression link
3 Subframe body mounts
4 Front cross link valve
5 Anti-roll bar
6 LH front strut assembly
7 LH compression link
8 LH front hub assembly
9 LH transverse link
10 LH anti-roll bar link
11 LH front height sensor
12 Front subframe
13 RH front height sensor (hidden)
14 RH transverse link
15 RH anti-roll bar link
16 RH front hub assembly
Struts
The front suspension struts are a MacPherson twin tube design with the conventional coil spring replaced by an air
spring. The lower end of the strut is connected to the front hub assembly with two bolts. The upper top mount is
attached to the inner wing with three studs and nuts.
The top mount has a bearing installed which reduces the force required on the steering when the strut rotates. A paper
gasket is fitted on the underside of the inner wing, between the inner wing and the top mount. The gasket prevents
the ingress of dirt and moisture into the bearing. When the strut is removed, this gasket must be replaced with a new
item to maintain the performance of the bearing and care must be taken to ensure that the gasket is correctly
positioned.
The damper functions by restricting the flow of hydraulic fluid through internal galleries within the damper. A damper
rod moves axially within the damper. As the rod moves, its movement is limited by the flow of fluid through the galleries
thus providing damping of undulations in the terrain. The damper rod is sealed at its exit point from the damper body
to maintain fluid within the unit and to prevent the ingress of dirt and moisture. The seal also acts as a wiper to keep
the rod outer diameter clean.
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SUSPENSION
DESCRIPTION AND OPERATION 60-5
The air spring is fitted on the upper part of the strut. Within the strut module the air spring elements comprise a top
plate assembly, an air bag and a base piston. The air bag is attached to the top plate and the piston with a crimped
ring. The air bag is made from a flexible rubber material which allows the bag to expand with air pressure and deform
under load. On the side of the top cap is a connector which allows for the attachment of the air hose from the cross-
link valve. The piston is made from plastic and is shaped to allow the air bag to roll over its outer diameter.
Subframe
The subframe is fabricated from steel tubing to provide a robust platform for the mounting of the suspension and
engine. The subframe is attached to the vehicle body via six mountings.
The subframe fabrication provides accurate location for the suspension components and the steering rack. Additional
brackets allow for the attachment of the height sensors and the engine mountings. The anti-roll bar is attached across
the rear of the subframe and is mounted in flexible bushes which are secured with 'D' shaped clamp plates.
Anti-Roll Bar and Links
The anti-roll bar is fabricated from 30mm diameter, solid spring steel bar. The anti-roll bar operates, via a pair of links,
from a bracket mounted on each strut.
The anti-roll bar is attached to the rear of the subframe with two bushes which are bonded to the bar and cannot be
removed. Clamp plates are pressed onto the bushes and must not be removed. The anti-roll bar is secured to the
subframe with the clamp plates which are located on studs on the subframe and secured with nuts.
The ends of the anti-roll bar are attached to each strut spring seat via an anti-roll bar link. This arrangement allows
the anti-roll bar to act on a 1:1 ratio with the wheel travel providing maximum roll bar effectiveness. A hardened washer
is fitted between the ball joint and the strut mounting plate. The hardened washer prevents the ball joint damaging the
bracket, which could lead to loosening of the torque on the nut. When the link is removed from the strut, it is important
to ensure that the correct hardened washer is replaced in the correct position.
Each anti-roll bar link has a ball joint fitting at each end which improves response and efficiency. The top ball joint is
mounted at 90° to the axis of the link and attaches directly to the strut and is secured with a locknut. The lower ball
joint is mounted at 90° to the axis of the link. The ball joint attaches to the anti-roll bar and is secured with a locknut.
The link must be attached to the anti-roll bar with the ball joint on the outside of the bar and the locknut facing inwards.
The ball joints on the anti-roll bar links are not serviceable and if replacement of either is necessary, a new anti-roll
bar link will be required.
Suspension Links
Transverse Link
The front suspension hub assembly is secured to the subframe via two suspension links. Each transverse link is fitted
with a bush which is secured with a bolt between two brackets on the subframe. The opposite end of the transverse
link is fitted with a ball joint which attaches to the hub assembly.
Compression Link
The compression is located rearward of the transverse link. The compression link is fitted with a compliance bush
which is secured with a bolt between two brackets on the subframe. The opposite end of the compression link has a
tapered hole which locates on a ball joint which is bolted to the hub assembly.
Hub Assembly
The hub assembly comprises a swivel hub, drive flange and bearing. A seal and bearing are fitted in the swivel hub
and are secured with a circlip. The drive flange has the wheel studs attached to it and locates on the splined drive
shaft and is secured with a stake nut.
The forged swivel hub has a vertical boss with two cross holes. This provides location for the strut assembly which is
secured with bolts and nuts to the swivel hub. Two additional bosses provide location for the brake calliper.
The lower part of the swivel hub has two threaded holes which allow for the attachment of the ball joint which locates
the outer end of the compression link. A further tapered hole allows for the attachment of the transverse link ball joint.
A hole is machined at 90° to the hub bearing. This hole allows for the fitment of the ABS speed sensor which is
secured with a screw into an adjacent threaded hole. The speed sensor reads off a target which is part of the drive
shaft assembly.
SUSPENSION
60-6 DESCRIPTION AND OPERATION
Rear Suspension
1 Subframe mounts
2 RH air spring
3 RH lower wishbone
4 Anti-roll bar
5 LH air spring
6 LH lower wishbone
7 Rear cross link valve
8 RH rear hub assembly
9 RH damper
10 RH upper wishbone
11 LH damper
12 Compressor assembly
13 LH rear hub assembly
14 LH toe control arm
15 LH upper wishbone
16 LH rear height sensor
17 Rear subframe
18 RH rear height sensor
19 RH toe control arm
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SUSPENSION
DESCRIPTION AND OPERATION 60-7
The independent rear suspension offers a reduction of un-sprung mass over the conventional beam axle design. The
suspension arms have been designed for maximum ground clearance. Wheel alignment can be adjusted for camber
and toe-in using eccentric bolts.
The following wheel travels are shown for on road and off-road vehicle operation. The difference between the two
operating conditions is a result of operation of the rear cross-link valve. When the cross-link valve is opened the
suspension travel is as given for off-road wheel travel. When the cross-link valve is closed the suspension travel given
for on road applies.
The off road mode wheel travel is:
l 190 mm bump
l 140 mm rebound
l This gives a total of 330 mm off road suspension travel.
The on road standard height wheel travel is:
l 140 mm bump
l 190 mm rebound
l This gives a total of 330 mm on road suspension travel.
The rear suspension comprises:
l Two dampers
l Two air springs
l Subframe
l Two upper wishbones
l Two lower wishbones
l Two toe control arms
l Anti-roll bar
l Anti-roll bar links
l Two hub assemblies.
Dampers
The rear dampers are unique to New Range Rover and are of a mono-tube design manufactured by Bilstein. The
mono-tube design gives the following advantages over conventional twin tube dampers:
l Lightweight construction
l Excellent high frequency response
l Consistent performance – mono-tube design eliminates fluid aeration and emulsification
l Larger diameter piston produces increased fluid displacement for a given damper stroke resulting in more
accurate damping control.
The damper comprises a single tube which forms the operating cylinder. The lower end of the cylinder has an eye
which accepts the bush for mounting to the lower wishbone. A piston and rod slides inside the cylinder. The rod
emerges from the top of the cylinder which is fitted with a rod guide and a seal.
A dust cover is fitted to the top of the rod and protects the rod from damage. A bump stop is fitted to the top of the
piston rod, under the dust cover, and protects the damper from full travel impacts. A top mount is fitted at the top of
the piston rod and is secured with a flanged nut. A hardened washer is fitted between the shoulder on the piston rod
and the bump washer which is fitted inside the dust cover. When the damper is removed and replaced, care must
taken to ensure that the correct hardened washer is refitted in the correct position. The washer prevents the piston
rod shoulder causing damage to the bump washer.
The piston is fitted with reed valves which cover a series of holes, through which oil can pass. A chamber at the base
of the damper is sealed by a free floating piston. The chamber is filled with inert gas. When the damper is assembled
and filled with oil, the gas is in a compressed condition below the piston. On the bump stroke, the downward
movement of the piston displaces oil from the full area (bottom) of the cylinder to the cylinder annulus (top). The
energy required to pump the oil through the piston drillings and reed valves creates the damping action.
As the piston moves downwards, the volume available on the annulus side of the piston is less than required by the
displaced oil from the full area side. When this occurs, the free floating piston moves downwards, further compressing
the gas and providing the additional volume for the displaced oil and further enhancing the damping process.
SUSPENSION
60-8 DESCRIPTION AND OPERATION
The dampers are located between the lower wishbone and the vehicle body. The lower mounting is fitted with a bush
which provides for the attachment to the wishbone with a bolt and nut. The damper top mounting is located in a turret
in the body and secured to the body with three nuts. A paper gasket is located between the damper top mounting and
the body and prevents the ingress of dirt and moisture into the mounting studs and corresponding holes in the body.
It is important that this gasket is discarded and replaced with a new item when the damper is removed.
Air Springs
Each air spring comprises a top plate assembly, an air bag and a base piston. The air bag is attached to the top plate
and the piston with a crimped ring. The air bag is made from a flexible rubber material which allows the bag to expand
with air pressure and deform under load. The top plate assembly comprises the plastic top plate with a spigot which
protrudes through a hole in the subframe. On the side of the top cap is a connector which allows for the attachment
of the air hose from the cross-link valve. The piston is made from plastic and is shaped to allow the air bag to roll over
its outer diameter. The base of the piston has a splined stud in the centre and an offset timing peg for correct
orientation of the air spring into the lower wishbone.
The air springs are located rearward of the dampers and are retained between the subframe and the lower wishbone.
The air spring is attached to the lower wishbone with a screw which is fitted from the underside of the wishbone into
the splined stud on the base of the piston. The air spring top plate is attached to the subframe via an integral 'D'
shaped spigot which is secured with a retaining clip.
Subframe
The subframe is fabricated from steel tubing to provide a robust platform for the mounting of the suspension and the
rear differential. The subframe is attached to the vehicle body via four, voided rubber mounts.
The subframe provides location for the suspension components and the rear differential. Two bushes at the front of
the subframe and one at the rear allow for the attachment of the rear differential. Additional brackets, bolted to the
subframe, allow for the attachment of the height sensors. The anti-roll bar is attached across the rear of the subframe
and is mounted in flexible bushes which are secured with 'D' shaped clamps.
Upper and Lower Wishbones
Upper Wishbone
The steel fabricated upper wishbone has two bushes pressed into housings which provide for the attachment to the
subframe. The bushes are located between brackets on the subframe and are secured with bolts and nuts. The outer
end of the upper wishbone has two brackets with slotted holes. A boss on the hub is fitted with a ball joint which locates
between the brackets and is secured with an eccentric bolt, washer and nut. This allows for the adjustment of the rear
wheel camber. Rotation of the bolt moves the eccentric head against a recessed slot in the bracket, moving the
location of the hub in the upper wishbone slots, allowing the camber to be adjusted to within the set limits. A rubber
bump stop is fitted centrally on the upper wishbone to cushion the wishbone movement when the suspension is at the
extremes of its travel.
Lower Wishbone
The lower wishbone is larger than the upper wishbone and is a steel fabrication. Two bushes are pressed into the
wishbone and provide for the attachment to the subframe. The bushes are located between brackets on the subframe
and secured with bolts and nuts. The lower wishbone has a platform which provides for the attachment of the air
spring. A welded bracket allows for the attachment of the anti-roll bar link. A boss on the hub is fitted with a ball joint
which locates between brackets on the lower wishbone. The hub is secured to the lower wishbone with a bolt and nut.
A bracket with a tubular extension provides for the attachment of the damper lower mounting.
Toe Control Arms
The toe control arm is a forged steel component. One end is fitted with a taper ball joint and the opposite end has a
bush pressed into an integral housing.
The bush locates between brackets on the subframe and is secured with a special eccentric bolt, washer and nut.
This allows for the adjustment of the rear wheel toe in. Rotation of the bolt moves the eccentric head within a recessed
slot in the bracket, allowing the toe-in to be adjusted within the set limits.
The taper ball joint locates in a tapered hole in the hub and is secured with a nut.
SUSPENSION
DESCRIPTION AND OPERATION 60-9
Anti-Roll Bar and Links
The anti-roll bar is fabricated from 23 mm diameter, solid spring steel. The anti-roll bar operates, via a pair of links,
from a bracket on the upper face of each lower arm.
The anti-roll bar is attached to the rear of the subframe with two bushes which are bonded to the bar and cannot be
removed. Clamp plates are pressed onto the bushes and must not be removed. The anti-roll bar is secured to the
subframe with the clamp plates which are secured with bolts. The ends of the anti-roll bar are attached to the lower
arms via anti-roll bar links. This arrangement allows the anti-roll bar to act on a 1:1 ratio with the wheel travel providing
maximum effectiveness. A hardened steel washer is fitted between the ball joint and the lower wish bone bracket. The
hardened washer prevents the ball joint damaging the bracket which could lead to loosening of the torque nut. When
the link is removed it is important to ensure that the correct hardened washer is replaced in the correct position.
Each anti-roll bar link has a ball joint fitting at each end which improves response and efficiency. The top ball joint is
mounted at 90° to the axis of the link and attaches to the anti-roll bar and is secured with a nut. The lower ball joint is
also mounted at 90° to the axis of the link. The ball joint attaches to the lower arm and is secured with a nut. The ball
joints on the anti-roll bar links are not serviceable and if replacement of either is necessary, a new anti-roll bar link will
be required.
Hub Assembly
The hub assembly comprises a wheel hub, drive flange and bearing. A seal and bearing are fitted in the wheel hub
and are secured with a circlip. The drive flange has wheel studs attached to it and locates on the splined drive shaft
and is secured with a stake nut.
The cast wheel hub has a vertical boss with a cross hole. A ball joint is pressed in the hole and provides the attachment
point for the upper wishbone. The upper wishbone is secured to the wheel hub with a bolt and nut. An additional boss
with two cross holes provide location for the brake calliper.
A second vertical boss with a cross hole at the bottom of the wheel hub provides for the attachment of the lower
wishbone. A ball joint is pressed in the hole and the lower wishbone is secured with a bolt and nut. A further tapered
hole in the wheel hub allows for the attachment of the toe control arm ball joint.
A hole is machined in the wheel hub at 90° to the hub bearing. This hole allows for the fitment of the ABS speed sensor
which is secured with a screw into an adjacent threaded hole. The speed sensor reads off a target which is part of the
drive shaft assembly.
Air Suspension
The air suspension comprises the following:
l Two front struts incorporating air springs
l Two rear air springs
l Two cross link valves
l An air reservoir, pressure sensor and valve block
l Four height sensors
l Air supply unit
l Air suspension ECU
l Air supply pipes
l External pressure relief valve (only on systems with a lower maximum operating pressure)
l Air suspension fascia control switch.
The air suspension system is controlled by the air suspension ECU which is located adjacent to the passenger
compartment fusebox, behind the fascia. The ECU is located in a white coloured plastic bracket for identification.
Suspension geometry changes when moving from off-road to access heights. See the following table for data:
Front Rear
Toe change 30 mins 10 mins
Camber change 90 mins 90 mins
SUSPENSION
60-10 DESCRIPTION AND OPERATION
Cross Link Valves
1 Electrical connector
2 RH air spring supply/return
3 RH air spring supply/return from valve block
4 Cross link valve body
5 LH air spring supply/return
6 LH air spring supply/return from valve block
The cross-link valves are located at the rear of the front RH wheel arch, behind the liner for the front valve and at the
top of the rear RH wheel arch, behind the liner for the rear valve. The valves are attached to the body by three fixing
and are rubber mounted to isolate solenoid noise.
The cross-link valves comprise a single large solenoid valve with connections to the LH and RH air springs and also
connections for each air spring from the reservoir mounted valve block. The solenoid operated valve is controlled by
the air suspension ECU. When the solenoid is energised, the cross-link valve connects the two air springs together,
allowing air to flow between them if required. This provides additional articulation of the suspension improving the off-
road capabilities of the vehicle and an improvement in low speed ride comfort.
The air suspension ECU senses that the vehicle is off-road by comparing rapid changes in signals from the height
sensors. The operation of the cross-link valves is fully automatic, requiring no driver intervention.
The cross link valves are only operated at vehicle speeds of 12.5 mph (20 km/h) and below. At vehicle speeds above
12.5 mph (20 km/h), the cross link valves remain closed.
SUSPENSION
DESCRIPTION AND OPERATION 60-11
Air Supply Unit
1 Electric motor
2 Compressor
3 Compressor temperature sensor
4 Electrical and air supply connectors
5 High pressure exhaust valve
6 Rubber mounting (3 off)
7 Exhaust hose
8 Exhaust pilot valve
The air supply unit is located in a sealed housing which is mounted in the spare wheel well. The unit is secured with
four bolts into threaded inserts in the vehicle floorpan. The unit is connected to the system via a single air pipe and
harness wiring and multiplug. The air pipe from the unit passes through a grommet in the wheel well. It is important
to ensure that this grommet is not disturbed and correctly installed. Incorrect fitment will allow water to enter the wheel
well leading to possible damage to and failure of the air supply unit.
The unit comprises a piston compressor, a 12V electric motor, a solenoid operated exhaust pilot valve, a pressure
relief valve and an air dryer unit.
The electric motor, compressor, air dryer and pressure limiting and exhaust valve are mounted on a frame which in
turn is mounted on flexible rubber mountings to reduce operating noise.
Removal of the air supply unit does not require depressurisation of the air suspension system. The corner and the
reservoir valves close, retaining the air in the system.
SUSPENSION
60-12 DESCRIPTION AND OPERATION
The electric motor drives a crank with an eccentric pin to which a connecting rod is attached. The connecting rod has
a piston which fits in the bore of the compressor. Operation of the motor rotates the crank, moving the piston in the
bore of the compressor. The compressor is attached with special bolts to the motor housing and sealed with an O-
ring. The compressor has a temperature sensor located in its housing. The sensor measures the compressor
temperature which is measured by the air suspension ECU.
Attached to the compressor is the air dryer which contains a silicate box for removing moisture from the compressed
air. Air supplied to inflate the air springs passes through the air dryer. When the air springs are deflated, the exhaust
air also passes through the air dryer, removing the moisture from the unit.
Attached to the end of the air dryer unit is a solenoid operated exhaust pilot valve. This valve is opened when the air
springs are to be deflated.
Located in the same housing as the exhaust pilot valve is a pressure limiting valve which, on systems without an
external pressure relief valve, protects the air springs from over inflation. The valve is pneumatically operated,
responding to air pressure applied to it to overcome pressure from a spring located behind the valve. The pressure
limiting valve also operates when the exhaust pilot valve is opened, allowing air returning from the air springs to be
exhausted.
The compressor is used to supply air pressure to the air suspension reservoir. The ECU monitors the pressure within
the reservoir and, when the engine is running, maintains a pressure of:
l 13.7 bar (199 lbf/in
2
), in systems without an external pressure relief valve
l 11.8 bar (171 lbf/in
2
), in systems with an external pressure relief valve
There are a number of conditions that will inhibit operation of the air suspension compressor. It is vitally important that
these inhibits are not confused with a system malfunction. A full list of compressor inhibits is contained in the Air
Suspension Control section.
A temperature sensor is located within the compressor. If the compressor temperature rises above set limits, the ECU
will inhibit compressor operation.
SUSPENSION
DESCRIPTION AND OPERATION 60-13
Reservoir
1 Reservoir mounting screw – front
2 Reservoir mounting screw – rear
3 Air pressure sensor
4 Reservoir
5 Air hose connectors
6 Hose – reservoir pressure to valve block
7 Valve block
The air suspension reservoir is fabricated from aluminium and is located under the RH sill of the vehicle. The reservoir
is secured with four bolts to the underside of the vehicle. The reservoir has an additional bracket on the forward facing
end which provides the mounting for the valve block. A pressure sensor is screwed into the rear face of the reservoir.
The sensor is connected to the air suspension ECU and measures the pressure within the reservoir. The pressure
sensor cannot be replaced. If failure of the sensor occurs, the reservoir, complete with the sensor must be replaced.
The reservoir supplies pressurised air to the four air springs, via the valve block, to enable the air suspension system
to carry out ride height changes.
Valve Block
The five way air suspension valve block is located under the RH sill of the vehicle, and is mounted forward of the air
reservoir. The valve block is held in place on the air reservoir support bracket by 3 studs and secured by nuts. The
studs are bonded into rubber mounts which isolates solenoid operation from the vehicle.
The valve block contains five solenoid operated valves which are controlled by the air suspension ECU. Four of the
valves, known as corner valves, control the air flow to and from air springs, via the cross-link valves. The fifth valve,
known as the reservoir valve, controls the air pressure supply from the reservoir to the air springs, via the corner
valves and cross-link valves and also from the compressor to the reservoir.
Removal of the valve block will require full depressurisation of the air suspension system. The valve block is a non-
seviceable item and should not be disassembled.
SUSPENSION
60-14 DESCRIPTION AND OPERATION
Height Sensors
1 Bracket – front sensor
2 Screw
3 Nut
4 Connecting link
5 Nut
6 Electrical connector
7 Sensor
8 Bolt
9 Nut
10 Connecting link
11 Bracket – rear sensor
A height sensor is fitted in each corner of the vehicle to monitor the ride height of the vehicle. The sensors are mounted
on the front and rear subframes, with a mechanical link to the suspension lower arms. There are six different types of
sensor fitted to Range Rover:
l LH front height sensor – All vehicles
l RH front height sensor – Halogen headlamps fitted
l RH front height sensor – Xenon headlamps fitted
l LH rear height sensor – All vehicles.
l RH rear height sensor – Halogen headlamps fitted
l RH rear height sensor – Xenon headlamps fitted.
NOTE: RH front and RH rear height sensors fitted to vehicles with Xenon headlamps have a white stripe across the
back face of the sensor housing for identification.
The height sensors are attached to brackets on the subframes and are connected to the lower arms by links. The links
allow articulation of the arm to allow for suspension travel. Each sensor is connected by a six pin multiplug. Standard
height sensors use three of the six pins and height sensors for vehicles fitted with xenon headlamps use all six.
The height sensors contain a circuit board with a Hall effect sensor. The sensor is supplied with a reference voltage
from the air suspension ECU which measures the returned voltage to determine the sensor arm position. The sensors
used on vehicles with xenon headlamps use a sensor with a second circuit. This second circuit is used by the xenon
headlamp levelling ECU.
The front sensor ball jointed linkage is a serviceable item. The rear sensor linkage cannot be serviced and must be
changed as a complete assembly.
SUSPENSION
DESCRIPTION AND OPERATION 60-15
Air Springs
1 Cover
2 Seal plate
3 Nut
4 Front air spring
5 Air hose connector
6 Rear air spring
The air springs on the front and rear suspension are similar in construction. The air springs are manufactured from a
flexible rubber. Each air spring forms an air tight cavity which provides the required spring rate for each corner of the
vehicle.
As the air spring is compressed, the rubber material compresses and rolls down the side of the vertical housing below
the spring. An air connection port is located on the top of each spring and allows air to be added or removed from
each spring. The port is connected via a Voss connector and a plastic tube to the valve block on the reservoir.
Replacement of an individual air spring does not require a full depressurisation of the air suspension system. Only the
corner concerned need be depressurised.
When servicing of an air spring or a full system depressurisation is required, the weight of the vehicle must be
supported before the system is depressurised. On reassembly, the air spring must be fully pressurised before the
weight of the vehicle is applied to it.
Air Pipes
The system is interconnected via yellow and black nylon pipes. The yellow pipes denote RH side and the black pipes
denote LH side. The pipes are attached to the subframes and vehicle body with clips. To ensure that the correct
routing is maintained, the pipes have timing marks which align with various clip positions. The timing marks are in the
form of a white band around the pipe, indicating the clip position. If the correct routing is not achieved, unnecessary
tension at the pipe joints will occur resulting in possible early failure.
SUSPENSION
60-16 DESCRIPTION AND OPERATION
External Pressure Relief Valve
On vehicles from VIN 106310 onwards, the maximum system pressure was reduced from 13.7 to 11.8 bar (199 to
171 lbf/in
2
) with the introduction of a new level of software for the air suspension ECU. For systems running with the
higher operating pressure, a relief valve in the air supply unit protects the subsequent components in the circuit. The
relief valve in the air supply unit became redundant with the introduction of the lower maximum system pressure, so
an external pressure relief valve was introduced to maintain protection.
The external pressure relief valve is installed in the air pipe between the compressor and the reservoir, in the front
right corner of the spare wheel well. If the pressure of the air from the compressor increases to 12.3 bar (178 lbf/in
2
),
the external pressure relief valve opens and releases excess pressure to atmosphere.
External Pressure Relief Valve Location
Leak Detection
Leak detection can be carried out using a Land Rover approved leak detection spray.
If the vehicle appears to be leaking, perform a leak check on all aspects of the system, i.e.; air spring hose fittings and
the associated connections on the valve block and cross-link valve, air springs, reservoir. Failure to correctly diagnose
leakage will result in unnecessary exchange of serviceable components and recurrence of original problem.
Air Suspension ECU
The air suspension ECU monitors vehicle ride height via four height sensors. The ECU has three modes of operation:
l Normal
l Periodic Wake-Up
l Transportation.
When a new air suspension ECU is fitted, the air suspension system will not function until configured with TestBook/
T4.
SUSPENSION
DESCRIPTION AND OPERATION 60-17
Normal Mode
The air suspension ECU will enter normal mode when it receives a 'wake up' signal from the Body Control Unit (BCU).
The BCU will provide the 'wake up' signal when the following occurs:
l A door is opened.
l The vehicle is unlocked using the remote handset.
l The ignition is switched on.
The BCU will continue to supply the 'wake up' signal for 15 minutes after the ignition is switched off. The air
suspension ECU will then remain active for a further 10–15 seconds to enable any new data to be written to its
Electronic Erasable Programmable Read Only Memory (EEPROM).
If the BCU has supplied a 'wake up' signal, but the ignition is off, the air suspension ECU will enter an Inactive Mode.
Under these circumstances, air suspension functionality is reduced. Although the air suspension ECU will continue to
monitor vehicle ride height and make any necessary adjustments, to keep the vehicle at the correct height, all ride
height selections made via the rotary switch will be ignored. The ECU will not illuminate the LED's or allow the
compressor to fill the reservoir. If a height increase is necessary and the pressure in the air reservoir is below 9 bar
(130 lbf/in
2
), the ECU will power the compressor to raise the vehicle back to the correct height.
If the ignition is switched on but the engine is not running, the air suspension ECU will continue to monitor vehicle ride
height and make any necessary adjustments. Downwards ride height selections made via the rotary switch will be
accepted, and the LED's will illuminate as normal. Upward ride height selections made via the rotary control switch
will be rejected. However, if the vehicle height decreases (e.g. if a load is added to the car), the ECU will return the
vehicle to the current ride height. These height changes are made using the air suspension reservoir providing the
available air pressure is more than 9 bar (130 lbf/in
2
). If the air pressure is less than 9 bar (130 lbf/in
2
), the compressor
is used for the height changes. Filling of the reservoir remains inhibited.
Periodic Wake-Up Mode
When the 'wake up' signal is removed by the BCU, the air suspension ECU powers down. After it powers down, the
air suspension ECU will wake up approximately every six hours and level the vehicle ride height. The air suspension
ECU will determine which corner of the vehicle is lowest, and adjust the remaining corners to the same level. This
action takes approximately 6–10 seconds to perform. The air suspension ECU will then remain active for a further 10–
15 seconds to enable any new data to be written to its EEPROM.
If the air suspension ECU fails to level the vehicle (if there is an obstruction beneath the vehicle for instance), periodic
wake-up mode will be suspended until the air suspension ECU receives a wake-up signal from the BCU.
NOTE: The air suspension ECU will not raise the vehicle in this mode.
Transportation Mode
To enable the vehicle to be delivered safely from the factory to the dealership, the air suspension system is set in
transportation mode. When the engine is running, the ride height will be set at 'Transportation High', which is 20 mm
below standard ride height. All four LED's will remain illuminated.
When the engine is not running, the air suspension ECU will drop the ride height by 40 mm (Transportation Low). All
four LED's will flash.
When the ride height is at 'Transportation Low' the vehicle can be lashed to a transporter, without the risk of loosening
due to the suspension ride height lowering.
SUSPENSION
60-18 DESCRIPTION AND OPERATION
Air Suspension ECU Harness Connectors
Air Suspension ECU Harness Connector C0867 Pin Details
Pin No. Description Input/Output
1 Not used –
2 CAN bus high Input/Output
3 Control switch up selection Input
4 Control switch hold selection Input
5 Control switch motorway ride height LED Output
6 Front RH corner valve control Output
7 Front LH and RH corner valves power supply Output
8 Front LH corner valve control Output
9 Rear RH corner valves control Output
10 Rear LH and RH corner valves power supply Output
11 Rear LH corner valve control Output
12 Reservoir valve control Input
13 Reservoir valve power supply Output
14 Exhaust pilot valve power supply Output
15 Exhaust pilot valve control Output
16 Air suspension compressor rrelay control Output
17 High pressure exhaust valve power supply Output
18 and 19 Not used –
20 CAN bus low Input/Output
21 Control switch down selection Input
22 Control switch off-road ride height LED Output
23 Control switch access ride height LED Output
SUSPENSION
DESCRIPTION AND OPERATION 60-19
Air Suspension ECU Harness Connector C2030 Pin Details
24 Front RH height sensor signal Input
25 Front LH height sensor signal Input
26 Rear RH height sensor signal Input
27 Rear LH height sensor signal Input
28 Air pressure sensor signal Input
29 and 30 Not used –
31 Temperature sensor Input
32 Front LH height sensor power supply Output
33 Front RH height sensor power supply Output
34 Air pressure sensor power supply Output
35 High pressure exhaust valve control Output
36 Not used –
37 K bus Input/Output
38 Wake up signal Input
39 Access mode selection switch (on driver's door module) Input
40 Control switch standard ride height LED Output
41 Control switch hold switch LED Output
42 Front RH height sensor ground –
43 Front LH height sensor ground –
44 Rear RH height sensor ground –
45 Rear LH height sensor ground –
46 Air pressure sensor ground –
47 and 48 Not used –
49 Temperature sensor ground –
50 Rear RH height sensor power supply Output
51 Rear LH height sensor power supply Output
52 to 54 Not used –
Pin No. Description Input/Output
1 Not used –
2 Front cross link valve control signal Output
3 Rear cross link valve control signal Output
4 Not used –
5 Ground –
6 Not used –
7 Rear cross link valve power supply Output
8 Front cross link valve power supply Output
9 Not used –
10 Battery power supply Input
Pin No. Description Input/Output
SUSPENSION
60-20 DESCRIPTION AND OPERATION
Air Suspension Control
Air Suspension Control Switch
1 Driver's door module access switch
2 Air suspension rotary control switch
3 Air suspension LED display
The air suspension ECU is able to provide four different ride heights:
l Standard
l Off-road
l Motorway
l Access.
The ride heights are selected via the rotary control switch mounted on the centre console. Rotating the switch upwards
or downwards selects a different ride height (providing all the criteria outlined below are met). The centre of the rotary
switch contains the 'Hold' switch. The 'Hold' switch prevents the air suspension ECU from automatically changing from
the currently selected ride height, and prevents the user selecting a new ride height.
2
3
M60 0839
1
SUSPENSION
DESCRIPTION AND OPERATION 60-21
Next to the rotary control switch are mounted a series of four LED's. An illuminated LED indicates which ride height
is active. If a new ride height is selected using the rotary control switch, the 'current' height LED remains illuminated
and the 'requested' height LED flashes until the vehicle achieves the new ride height. If a new ride height is selected
using the rotary control switch and the 'current' height LED flashes briefly, this indicates that the ride height selection
is invalid and will not be performed. When the operating parameters are correct for the new ride height, the height
change request must be repeated.
Standard Ride Height
Standard ride height is used during most driving conditions. This setting is used as a datum for the remaining ride
heights, and is defined as 0 mm. All other ride height settings are described as above or below this setting. The
standard ride height can be active at any vehicle speed.
Access or off-road ride height can be selected from standard ride height using the rotary control or the drivers door
access switch.
When the vehicle is in standard ride height, the 'Hold' switch can be selected. This prevents automatic height changes
from taking place and disables manual height changes until the 'Hold' switch is deselected. If a height change is
selected with the hold function active, the standard height LED will flash.
When towing, the electrical connection of the trailer socket will cause the vehicle to set the air suspension to standard
height. No other height setting is available whilst towing.
Off-Road Ride Height
Off-road ride height is the highest of the four settings, and raises the front of the vehicle by 60 mm, and the rear of the
vehicle by 50 mm. Off-road ride height is selected by turning the rotary switch upwards when the vehicle is travelling
at less than 31 mph (50 km/h). The suspension will return to the standard ride height setting if the rotary control switch
is turned downwards, or vehicle speed rises above 31 mph (50 km/h).
If the vehicle is travelling too fast when off-road ride height is selected, the standard road height LED will flash, and
the request will not be carried out. The driver must repeat the off-road ride height request once the vehicle speed is
reduced.
When the vehicle is in the off-road ride height setting, the 'Hold' switch will not be operational. Similarly, if the vehicle
is in the standard ride height setting with 'Hold' selected, the vehicle will not move into the off-road ride height setting
until 'Hold' is deselected.
Motorway Ride Height
Motorway ride height lowers the vehicle by 20 mm, and improves the high speed handling of the vehicle. Motorway
ride height is only active when the vehicle is travelling at more than 62 mph (100 km/h) for more than 30 seconds, and
is not selectable by the driver.
If the vehicle speed falls to below 43 mph (70 km/h) for more than 60 seconds, the ECU automatically returns the
vehicle to the standard ride height setting. If the vehicle stops while the motorway ride height is active, the timer is
paused, stopping the vehicle rising unnecessarily.
Although motorway ride height isn't selectable by the driver, the 'Hold' switch can be used to keep the motorway ride
height active, and prevent the automatic return to the standard ride height. The vehicle will return to the standard ride
height once the 'Hold' switch is deselected (and vehicle speed is less than 43 mph (70 km/h).
Motorway ride height may be deselected by the driver at any speed by turning the rotary control switch upwards. The
vehicle may return to motorway ride height if the vehicle speed remains greater than 62 mph (100 km/h) and the driver
does not select 'Hold' when the vehicle has returned to standard ride height.
If the vehicle speed is within the required parameters, the driver can select access ride height by turning the rotary
control switch downwards or pressing the access switch on the drivers door.
Access Ride Height
Access ride height lowers the vehicle by 40 mm when the vehicle is stationary or moving at very low speeds in order
to improve ease of access to the vehicle. Access ride height can be selected by operating the access switch on the
drivers door module when the vehicle is in standard, off-road or motorway ride heights or by turning the rotary control
switch downwards when the vehicle is in standard or motorway ride heights.
SUSPENSION
60-22 DESCRIPTION AND OPERATION
Access ride height has three different modes of operation:
l Access Height
l Access Pre-Select
l Crawl Mode.
Access Height
If the vehicle is stationary or travelling at less than 15 mph (25 km/h) 'Access Height' mode can be selected. If vehicle
speed increases to more than 18 mph (30 km/h) the vehicle automatically returns to the standard ride height.
Access Pre-Select
If the vehicle is travelling below 49 mph (80 km/h) and access ride height is selected, the vehicle enters the 'Access
Pre-Select' mode. The ECU acknowledges this request by flashing the 'Access' LED, but the height of the vehicle
does not change immediately. If the vehicle is travelling above 49 mph (80 km/h) and access ride height is selected,
the 'Standard' LED will flash and the request will be denied.
When access pre-select mode is active, the vehicle will automatically lower to Access ride height if the speed drops
below 15 mph (25 km/h) within 65 seconds of the request being made. If the vehicle speed rises above 49 mph (80
km/h) after 'Access Pre-Select' mode is selected, or if it takes longer than 65 seconds to come to rest, access ride
height will not be activated and the vehicle will remain at its current height.
Crawl Mode
Crawl mode does not change the vehicle height, but inhibits manual height changes and allows the vehicle to be
driven at a higher speed than in normal access mode.
Crawl mode is activated when the vehicle is at the access ride height and 'Hold' is selected. If 'Access Height' has
been selected, but the air suspension ECU has not lowered the vehicle because the road speed is too high, when
'hold' is selected the 'Access Height' request is cancelled and the vehicle remains at standard ride height. The 'Hold'
button remains active so that all automatic and manual height changes are disabled.
Crawl mode allows the vehicle to be driven at speeds up to 25 mph (40 km/h) without returning to the standard ride
height. If the vehicle speed reaches 22 mph (35 km/h), a chime will sound from the instrument pack sounder and the
message centre will display a 'SLOW DOWN' warning message. If the vehicle speed exceeds 25 mph (40 km/h), crawl
mode is cancelled and standard ride height will become active automatically.
System Inhibits
A number of conditions exist where a change in ride height is undesirable. To counter this, the air suspension ECU is
programmed with a number of system inhibits. If any of the conditions detailed below exist, the air suspension ECU
will suspend height changes and height corrections.
Compressor
The temperature sensor located within the compressor protects the compressor from overheating. If the compressor
temperature rises above set limits, the ECU will inhibit compressor operation. These limits are shown in the table
below:
Compressor Timeout
Compressor operation will be halted after 180 seconds of continuous operation. If the compressor was attempting to
regulate vehicle height, it remains inhibited for 20 seconds. If the compressor was attempting to fill the air suspension
reservoir, it remains inhibited for 180 seconds. These time out functions act as a further safe guard against over
heating.
Filling
Reservoir
Height
Regulation
Stop 100 °C (212 °F) 110 °C (230 °F)
Start 80 °C (176 °F) 105 °C (221 °F)
SUSPENSION
DESCRIPTION AND OPERATION 60-23
Cornering
If the air suspension ECU registers a cornering force greater than 0.2g it will inhibit all height changes and corrections.
The system will remain inhibited until the cornering force falls to less than 0.15g for 0.5 seconds. The air suspension
ECU receives a message from the ABS sensor on the CAN Bus for the cornering force.
Rapid Acceleration
If the air suspension ECU registers a rapid acceleration greater than 0.2g it will inhibit all height changes and
corrections. The system will remain inhibited until the rapid acceleration falls to less than 0.2g for 1 second.
Acceleration is calculated by the ECU from a vehicle speed signal received via the CAN bus.
Rapid Deceleration
If the air suspension ECU registers a rapid deceleration smaller than – 0.2g it will inhibit all height changes and
corrections. The system will remain inhibited until the rapid deceleration rises above – 0.2g for 1 second. Deceleration
is calculated by the ECU from a vehicle speed signal received via the CAN bus.
Axle Articulation
To avoid excess pressure differentials between different air springs, the air suspension ECU will inhibit all height
changes and corrections if axle articulation is greater than 350 mm. The system will remain inhibited until axle
articulation falls below 350 mm.
Vehicle Lift
The air suspension ECU will inhibit all height changes and corrections if it detects all four corner heights are greater
than 90 mm. This is interpreted as the vehicle being on a wheels free car lift with all wheels hanging freely. In this
situation, the corner heights will not change when air is released from the air springs. The system will remain inhibited
until any of the following conditions exist:
l All four corner heights fall below 90 mm
l The rotary switch is moved to the 'UP' or 'DOWN' position.
l Vehicle speed rises to greater than 25 mph (40 km/h) for longer than 3 seconds.
Vehicle Jack
The air suspension ECU will inhibit all height changes and corrections if it detects a corner lowering too slowly for
more than 3 seconds. This is interpreted as the corner identified as moving too slowly being supported on a jack. In
this situation, the corner height will not change when air is released from the air spring because the jack acts as a
mechanical prop. The system will remain inhibited until any of the following conditions exist:
l The height of the wheel identified as lowering too slowly, returns to the height where jacking was detected.
l The rotary switch is moved to the 'UP' or 'DOWN' position.
l Vehicle speed rises to greater than 25 mph (40 km/h) for longer than 3 seconds.
Door Open
The air suspension ECU will stop all height change requests while any of the doors are open. Vehicle levelling is also
inhibited with a door open.
Trailer Mode
Using the electrical trailer connection will cause the air suspension to be set to standard height. If the vehicle is at any
other height when the trailer is connected the air suspension will adjust to standard height and stay in that mode until
the trailer is disconnected.
Diagnostics
The air suspension ECM can store fault codes which can be retrieved using TestBook/T4. The diagnostics information
is obtained via the diagnostic socket which is located in the fascia, in the drivers stowage tray. The socket is secured
in the fascia panel and protected by a hinged cover.
The diagnostic socket allows the exchange of information between the various ECU's on the bus systems and
TestBook/T4 or a diagnostic tool. This allows the fast retrieval of diagnostic information and programming of certain
functions using TestBook/T4 or a suitable diagnostic tool.
SUSPENSION
60-24 DESCRIPTION AND OPERATION
Fault Detection
The air suspension ECU performs fault detection and plausibility checks. Fault detection is limited to faults that the
ECU can directly measure, as follows:
l Sensor hardware faults
l Valve hardware faults
l Sensor and actuator supply faults
l Bus failures
l ECU hardware errors.
Plausibility checks are checks on signal behaviour, as follows:
l Average height does not change correctly
l Height changes too slowly
l Suspension moves in the wrong direction.
l Reservoir pressure
l Does not increase when reservoir filling requested
l Does not decrease when reservoir used to lift vehicle
l Does not decrease when reservoir is vented
l Pressure varies too much when inactive.
l Compressor temperature
l Increases when compressor inactive
l Does not increase when compressor active.
l 'Energy' used to change height of corner
l Too much 'energy' used – height change takes too long or long term filtered height does not reach target.
l Sensor activity
l Signal floating
l Inconsistent signal characteristics – signal on one side of axle is varying but other side remains static
l Constant articulation when moving.
When a fault is detected, the ECU will attempt to maintain a comfortable ride quality with restricted functionality of the
air suspension system.
The system functionality depends on the severity of the fault. The faults are defined as minor or major faults.
Minor faults are:
l Most sensor faults (hardware faults and plausibility faults)
l Cross link valve failure
l Reservoir valve failure.
For most minor faults, height changes are inhibited except for a return to standard height. If the suspension is not in
standard height, the ECU will respond to a request for manual or automatic height change to return the vehicle to
standard height. The ECU will continue to level the vehicle at the 'current' ride height.
Major faults are:
l Compressor faults
l Plausibility errors – for example:
l Average height does not increase when lifting and the vehicle is moving. This could be caused by a
compressor fault or a fault in the reservoir valve.
l Reservoir pressure decreases when filling requested. This could be caused by a leak in the common gallery
in the valve block or connecting pipe.
For major faults the ECU will not level the vehicle at the 'current' ride height. The ECU freezes height changes until it
receives a manual or automatic request for height change. The ECU will return to standard height and freezes once
standard height is achieved.
If the air suspension ECU loses information regarding vehicle speed, the ECU cannot determine if the current ride
height is suitable for the vehicle speed. The ECU immediately returns to the 'default' height, which is 20 mm below
the standard height. Once at the default height, the ECU will continue to level the vehicle at this height. A loss of the
speed signal could be due to a fault in the CAN Bus or a fault in the ABS ECU. It is unlikely to be a fault in the air
suspension ECU. It may, for example, be caused if the battery is disconnected and the steering sensor is not
recalibrated immediately after reconnection. In this case a CAN Bus fault is recorded in the error memory. If this fault
is seen, other ECU's using the CAN Bus should be also be checked for faults. When the fault is repaired, the air
suspension ECU will resume full functionality but the CAN error remains in the memory.
SUSPENSION
DESCRIPTION AND OPERATION 60-25
If the suspension is above the standard height and the air suspension ECU cannot lower the suspension or cannot
determine the vehicle height, all height changes will be frozen. The ECU will issue a message on the CAN Bus which
is received by the instrument pack which displays a maximum advisable speed in the message centre of '35MPH'. an
immediate 'freeze' of the vehicle height is caused by the following:
l Failure of more than one height sensor
l Implausible articulation symptoms detected
l Valve or solenoid failure (does not include reservoir valve)
l Stuck corner or whole vehicle (diagnosed using plausibility of the sensor inputs).
If the air suspension ECU has a hardware fault, the ECU will disable all air suspension functions. Detectable hardware
errors include memory error, ECU failure, calibrations errors.
Fault Messages
The air suspension has two methods which it can use to inform the driver of a fault in the air suspension system; the
air suspension control switch LED's and the instrument pack message centre.
When minor faults occur and the air suspension ECU is able to level the vehicle to the 'current' ride height, the control
switch LED's will display the current ride height. When the vehicle returns to the standard ride height and further height
changes are disabled, the 'HOLD' LED in the control switch will be permanently illuminated.
The air suspension ECU suffers a major failure and there is no air suspension control, all the control switch LED's will
remain unlit.
If a fault occurs and the ECU can determine the ride height and the vehicle is not above standard ride height, the driver
will be notified via a 'AIR SUSP. INACTIVE' message in the message centre. If the ECU cannot determine the height
of the vehicle, or the vehicle is above standard ride height and cannot be lowered, the 'AIR SUSP. INACTIVE'
message is accompanied with an alternating 'MAX 35MPH' message.
SUSPENSION
60-26 DESCRIPTION AND OPERATION
Operation
General
Under normal operating conditions, the air suspension ECU keeps the vehicle level at the 'current' ride height. The
incoming height signals from the sensors are passed through filters to remove irregular signals produced by road
noise or other irregularities. When the vehicle is stationary or a height change is in progress, the signals are passed
through a 'fast' filter, which tracks the true rate of change of height. When the vehicle is moving, the signals are passed
through a 'slow' filter. The 'slow' filtered signals remove almost all road noise from the signals and output a true long
term average for each corner height. The 'slow' filtered signals cannot be used to respond quickly during height
changes.
The air suspension ECU monitors each corner height signal using the fast filtered signals if the vehicle is stationary
or the slow filtered signals if the vehicle is moving. If the height remains in a 'dead band' which is ±10 mm from the
target height, the ECU does not implement any height adjustment changes. When the ECU detects that a corner has
moved outside of the 'dead band', the ECU operates the compressor and/or the valves to raise or lower the
corresponding corner(s) back into the target height.
When the engine is not running, the 'dead band' target height tolerance is increased to +20 mm and -25 mm. During
'wake-up', the tolerance band is ±20 mm. In all cases, the ECU will bring the corner height as close as possible to the
target height. The ECU monitors the rate of change of height of the corner signals to predict when to close the valve
so that the target height is not overshot.
Reservoir
The reservoir supplies pressurised air to the four air springs, via the valve block, to enable the air suspension system
to carry out ride height changes.
If an upwards height change request is made when the engine is not running, air pressure within the reservoir is used
to lift the vehicle. If the pressure within the reservoir has dropped below 9 bar (130 lbf/in
2
) when an upwards height
change request is made, the lift procedure is performed by the compressor. When the engine is started, the ECU runs
the compressor to increase reservoir pressure to:
l 13.7 bar (199 lbf/in
2
), in systems without an external pressure relief valve
l 11.8 bar (171 lbf/in
2
), in systems with an external pressure relief valve
SUSPENSION
DESCRIPTION AND OPERATION 60-27
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SUSPENSION
60-28 DESCRIPTION AND OPERATION
System Pneumatic Circuit
The following schematic diagram shows the connection relationship between the air supply unit, the reservoir, the
reservoir valve block, the cross-link valves and the air springs.
System Schematic Circuit Diagram
M60 0838A
1
2
3
4
9
10
11
14
18
19
15
16
20
M
5
6
7
8
12
13
21
22
17
SUSPENSION
DESCRIPTION AND OPERATION 60-29
1 Front LH damper air spring
2 Front cross link valve
3 Front RH damper air spring
4 Front LH corner valve
5 Reservoir valve
6 Front RH corner valve
7 Rear RH corner valve
8 Rear LH corner valve
9 Rear RH air spring
10 Rear cross link valve
11 Rear LH air spring
12 Compressor inlet/exhaust port
13 HP pressure exhaust valve
14 Exhaust pilot valve
15 Pressure limiting valve
16 Electric motor
17 External pressure relief valve (where fitted)
18 Restrictor
19 Drier
20 Compressor
21 Reservoir
22 Pressure sensor
SUSPENSION
60-30 DESCRIPTION AND OPERATION
BRAKES
DESCRIPTION AND OPERATION 70-1
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BRAKESDESCRIPTION AND OPERATION
BRAKES
70-2 DESCRIPTION AND OPERATION
Braking System Component Location
BRAKES
DESCRIPTION AND OPERATION 70-3
1 Brake fluid reservoir
2 Servo
3 Rear disc brake
4 Front brake disc
5 ABS control unit and hydraulic modulator
6 Brake master cylinder
7 Vacuum hose
8 Inlet manifold (petrol)
9 Vacuum pump
10 Vacuum hose
BRAKES
70-4 DESCRIPTION AND OPERATION
Front Brake Components
1 Brake pad wear detection sensor
2 Guide pin dust cover
3 Guide pin slider
4 Guide pin
5 Calliper carrier
6 Brake pad retainer
7 Mud shield retaining bolt
8 Brake disc
9 Brake disc retaining bolt
10 Mud shield
11 Calliper body
12 Piston seal
13 Piston dust cover
14 Mounting bolt
15 Bleed valve dust cap
16 Brake pads
17 Bleed valve
BRAKES
DESCRIPTION AND OPERATION 70-5
Rear Brake Components
1 Guide pin dust cover
2 Guide pin slider
3 Guide pin
4 Bleed valve dust cap
5 Bleed valve
6 Brake pad wear detection sensor
7 Calliper body
8 Piston seal
9 Piston dust cover
10 Brake disc retaining bolt
11 Brake disc retaining bolt dust cover
12 Mud shield retaining bolt
13 Mud shield
14 Brake disc
15 Brake pad retainer
16 Calliper carrier
17 Brake pad
18 Mounting bolt
19 Brake pad
BRAKES
70-6 DESCRIPTION AND OPERATION
Foundation Brakes
General
The brake system is a dual circuit type with Electronic Brake Force distribution (EBD) through DSC/ABS control. The
system comprises:
l Vacuum booster
l Tandem master cylinder with two central valves for DSC operation
l Brake fluid reservoir with reed contact fluid level switch
l Vented front discs/Solid rear discs
l Single piston calipers
l ABS hydraulic unit with integrated control module
l Pre-charge pump for DSC operation.
Front Brakes
The front brakes each comprise a hub mounted, single piston calliper assembly and a vented disc. The inboard side
of the disc is protected by a mud-shield. When hydraulic pressure is supplied to the calliper, the piston extends and
forces the inner pad against the disc. The calliper body reacts and slides on the guide pins to bring the outer pad into
contact with the disc.
Rear Brakes
The rear brakes each comprise a hub mounted, single piston calliper assembly and a solid disc. The operation is the
same as for the front brakes.
Both the left front inboard and right rear inboard brake pad wear is monitored by a sensor attached to the pad by a fly
lead. If the brake pad warning has been triggered the sensor and brake pads must be replaced.
Master Cylinder
The master cylinder assembly produces hydraulic pressure to operate the brakes when the brake pedal is pressed.
The assembly is attached to the front of the brake servo assembly, and comprises a cylinder containing two pistons
in tandem. The rear piston produces pressure for the primary circuit and the front piston produces pressure for the
secondary circuit.
The brake fluid reservoir is located on top of the master cylinder assembly. The reservoir is internally divided to
provide an independent supply of fluid to each brake circuit, and so prevent a single fluid leak from disabling both
primary and secondary brake circuits. Should a failure occur in one circuit, the remaining circuit will still operate
effectively, although brake pedal travel and vehicle braking distances will increase.
If the fluid level in the reservoir is too low, the brake fluid level switch in the reservoir filler cap breaks a contact to the
DSC ECU, which sends a CAN message to illuminate the brake warning lamp in the instrument pack and displays the
message 'CHECK BRAKE FLUID' in the instrument pack.
Brake Disc 344mm diameter -30 mm thick
Calliper Single piston 60mm diameter
Pads asbestos free
Brake Disc 354mm diameter -12mm thick
Calliper single piston 42mm diameter
Pads asbestos free
BRAKES
DESCRIPTION AND OPERATION 70-7
Brake Master Cylinder, Servo and Fluid Reservoir
1 Brake fluid level switch
2 Brake fluid reservoir
3 Retaining pin
4 Retaining nut
5 Plate
6 Retaining clip
7 Brake servo
8 O ring
9 Nut
10 Master cylinder assembly
11 Seals
BRAKES
70-8 DESCRIPTION AND OPERATION
Hydraulic Circuit
M70 1177
1
2
3
6
4
77
9
8
13
12
11
10
15
14
16
18
19
23
22
2120
17
17
1918
16
15
14
9
10
11
12
13
8
5
BRAKES
DESCRIPTION AND OPERATION 70-9
1 Fluid reservoir cap with fluid level sensor
2 Master cylinder
3 Pre charge pump motor
4 Brake pressure sensor
5 ABS pump motor
6 Pre charge pump
7 Damper
8 Separation valve
9 Solenoid valve
10 One way check valve
11 ABS pump
12 Check valve
13 Restrictor valve
14 Low pressure accumulator
15 Damper
16 Right Inlet valves
17 Left Inlet valves
18 Right outlet valves
19 Left outlet valves
20 Right rear brake
21 Left rear brake
22 Left front brake
23 Right front brake
BRAKES
70-10 DESCRIPTION AND OPERATION
When the brake pedal is pressed, the front push rod in the brake servo assembly pushes the primary piston along the
cylinder bore. This produces pressure in the primary pressure chamber which, in conjunction with the primary spring,
overcomes the secondary spring and simultaneously moves the secondary piston along the cylinder bore. The initial
movement of the pistons, away from the piston stops, closes the primary and secondary centre valves. Further
movement of the pistons then pressurizes the fluid in the primary and secondary pressure chambers, and thus the
brake circuits. The fluid in the chambers, behind the pistons, is unaffected by movement of the pistons and can flow
unrestricted through the feed holes between the chambers and the reservoir. When the brake pedal is released, the
primary and secondary springs push the pistons back down the bore of the cylinder. As the pistons contact the piston
stops, the primary and secondary centre valves open, which allows fluid to circulate unrestricted between the two
hydraulic circuits and the reservoir, through the centre valves, the chambers behind the pistons and the feed holes.
Brake Servo
The brake servo assembly provides power assistance to reduce the pedal load when braking. The assembly is
attached to the front of the pedal box and comprises a circular housing containing a diaphragm, push rods, valve and
filter. A push rod at the rear of the housing is connected to the brake pedal.
The vacuum line is connected to a port in the front face of the housing. With the brake pedal released and the engine
running, vacuum pressure is present on both sides of the diaphragm. When the brake pedal is pressed, the rear push
rod moves forward and opens the valve to allow atmospheric pressure through the filter into the pedal side of the
diaphragm. The pressure differential acting on the diaphragm increases the pressure being applied by the brake
pedal, which is transmitted to the master cylinder via the forward push rod. If the servo fails, the hydraulic system will
still function but will require greater pedal effort due to the lack of vacuum assistance.
BRAKES
DESCRIPTION AND OPERATION 70-11
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DESCRIPTION AND OPERATION
BRAKES
70-12 DESCRIPTION AND OPERATION
Dynamic Stability Control System
Control Diagram
A = Hardwired connection; C= DS2; D = CAN bus
22
M70 1189
20
1
A
4
5
6
7
9
10
11
12
13
14
18
17
16
15
21
24
23
19
2
25
26
D
27
8
C
3
BRAKES
DESCRIPTION AND OPERATION 70-13
1 HDC lamp
2 Handbrake warning lamp
3 Brake assist/brake warning lamp
4 Steering angle sensor
5 ECM
6 EAT ECU
7 Air suspension ECU
8 Transfer box ECU
9 Diagnostic socket
10 Parking brake switch
11 Fuse
12 Light check module (LCM)
13 Brake light switch
14 Brake pressure sensor
15 Wheel speed sensors
16 Wheel speed sensors
17 Wheel speed sensors
18 Wheel speed sensors
19 Fuse
20 DSC sensor
21 HDC switch
22 DSC hydraulic unit
23 Main relay
24 DSC switch
25 ABS lamp
26 DSC lamp
27 Instrument pack
BRAKES
70-14 DESCRIPTION AND OPERATION
Dynamic Stability Control
Introduction
The New Range Rover is equipped with Dynamic Stability Control (DSC) for enhanced braking and stability control.
Functions of the DSC include:
l Hill Decent Control (HDC)
l Electronic traction control (ETC)
l ABS
l Providing Corner Braking Control (CBC)
l Providing Emergency Brake Assist (EBA)
l Providing Electronic Brake Force Distribution (EBD).
Dynamic Stability Control System Components
Hydraulic Modulator
1 ABS ECU
2 Brake pressure sensor
3 Bolt washer
4 Spacer
5 Mounting bush
6 Bracket mounting bolt
7 Mounting bracket
BRAKES
DESCRIPTION AND OPERATION 70-15
The ECU is integrated into the hydraulic modulator as one compact unit. This reduces the size and wiring required for
DSC operation. Additionally the motor relay and valve relay have been replaced by solid state final stages in the
control module. The ECU and Hydraulic modulator are available as separate service components. The hydraulic unit
to uses:
l Two pre-charge solenoid valves
l Two change over solenoid valves
l Four intake solenoid valves
l Four outlet solenoid valves
l One return pump.
Pre-Charge Pump
1 Cap
2 Bolt
3 Rubber mounting washer
4 Spacer
5 Pre charge pump
6 Bolt
7 Clip
8 Mounting bracket
The pre-charge pump is located adjacent to the brake servo on the inner wing (handed).
At low brake fluid temperature the pre-charge pump removes back pressure from the master cylinder, sucks fluid from
the reservoir and adds it directly into the circuit. The pump is always used for DSC, HDC and ETC operation and is
controlled by the ABS ECU.
BRAKES
70-16 DESCRIPTION AND OPERATION
Dynamic Stability Control Sensor
1 DSC sensor
Located under the centre console, the dynamic stability control sensor provides two inputs to the ABS ECU, lateral
acceleration and rotational rate. The sensor is isolated from body/chassis vibrations through its rubber mounting.
For rotational speed, the sensor produces a reference signal of 2.5 volts and a linear voltage signal from 0.7 to 4.3
volts. This linear voltage input signal is used by the ABS ECU as the degree of rotational rate (yaw).
The sensor also produces a linear voltage signal for the lateral acceleration that ranges from 0.5 to 4.5 volts. The ABS
ECU uses this input to determine the side forces acting on the vehicle for DSC regulation.
The DSC sensor has diagnostic capability via the ABS ECU through TestBook/T4.
The DSC sensor also supplies the air suspension ECU cornering information.
BRAKES
DESCRIPTION AND OPERATION 70-17
Brake Pressure Sensor
1 Brake pressure sensor
A brake pressure sensor is installed in the hydraulic unit to determine the degree of pressure build up in the braking
system. It is installed in the front axle brake circuit.
The sensor receives its power supply from the ABS ECU and produces a linear voltage input signal ranging from 0.5
to 4.5 volts depending on the brake pressure in the circuit.
The brake pressure sensor is used for emergency brake assist and to calculate brake torque applied to each wheel
for all DSC functions. Torque is calculated using engine torque from the ECM, gear selected from the EAT ECU and
range selected from the transfer box ECU. The sensor is also used for brake temperature calculation.
BRAKES
70-18 DESCRIPTION AND OPERATION
HDC Switch
1 HDC switch
The Hill Descent Control function is activated by operating the HDC switch located to the left of the gear selector. The
green HDC information lamp in the instrument pack, will illuminate when the system is selected and available.
If the vehicle is outside of normal HDC operating parameters, the lamp only illuminates when switch is held. Message
centre displays the message 'NO HDC SLOW DOWN'.
BRAKES
DESCRIPTION AND OPERATION 70-19
DSC Switch
1 DSC switch
The DSC system is active whenever the ignition is switched on. When pressed, the switch provides a momentary 12
volt signal to the ABS ECU to switch the off the DSC function (DSC indicator in cluster illuminated.) When pressed
again, the DSC function switches back on (DSC Indicator in cluster goes off.)
The DSC function can determine if the vehicle is close to roll over and will cut engine torque to ensure that vehicle
speed does not increase, thus reducing the chance of vehicle rolling over.
If the DSC function fails, the air suspension drops to between standard and motorway height, to provide increased
stability.
BRAKES
70-20 DESCRIPTION AND OPERATION
Wheel Speed Sensors
1 Wheel speed sensor
2 Location bolt
3 Cable clip
4 Cable clip
5 Grommet
The wheel speed sensors are 2 wire Hall Effect type sensors. These sensors picks up on a 48 pulse incremental wheel
speed sensor pole wheel on the drive shaft. 48 pulses = one complete wheel revolution. The sensor receives a
stabilized 8 volt power supply to hall element on one wire, ground path for sensor through second wire back to the
ABS ECU. The signal is generated by the pulse wheel affecting voltage flow through the hall element creating a low
of 0.75 and a high of 2.5 volts. The sensors provide immediate vehicle speed recognition.
BRAKES
DESCRIPTION AND OPERATION 70-21
Steering Angle Sensor
1 Steering angle sensor
The Steering angle sensor is mounted at the bottom of the steering spindle at the base of the upper steering column
assembly.
The sensor is equipped with a processor and is directly linked to the CAN bus to communicate with the ABS ECU.
The sensor utilizes two potentiometers to determine the steering angle and the rate of steering. These are the raw
signals the steering angle microprocessor utilizes to create the steering angle signal for broadcast on the CAN bus.
The sensor requires calibration after repairs to the steering or suspension system. Once the calibration is completed
the sensor now also sends an identification number over the CAN bus to the ABS ECU. The ID provides confirmation
in the ABS ECU that the steering angle sensor is properly calibrated.
If the ID differs due to component replacement it will be necessary to enter the diagnostic system of the ABS system
to initiate the steering angle sensor calibration. DSC will not be available on the vehicle until the steering angle sensor
is calibrated. Once complete a new ID number is generated and the DSC ECU and Steering angle sensor are properly
mated.
The DSC logic checks the plausibility of the steering angle sensor against the other DSC inputs (front wheel speeds,
rotation and DSC sensor). If battery voltage is interrupted, the current steering wheel rotation is recalculated by the
ABS ECU evaluating the wheel speeds.
Replacement steering angle sensors must be coded when installed in the vehicle prior to the calibration procedure in
order to add the VIN to the angle sensor. Re-calibration is carried out by turning the steering lock to lock with the
engine running while stationary.
Brake Fluid Level Warning Switch
A fluid level switch is incorporated into the reservoir cap.
l With sufficient fluid level the reed contact is closed
l When level drops below allowable limits, switch opens.
Since the normal position is closed, this circuit is monitored for shorts to + and ground.
The ABS ECU monitors the fluid level and issues a low fluid level message on the CAN.
BRAKES
70-22 DESCRIPTION AND OPERATION
The LCM receives the message and illuminates the warning lamp and generates the low brake fluid message for the
message centre. If the ground signal is momentary, the LCM signals the Instrument cluster of the condition. The
instrument cluster then informs the ABS ECU over the CAN bus. If the signal is received prior to the activation of the
pre-charge pump, the pre-charge pump activation is delayed.
If the signal is present for more then 25 seconds, the LCM issues two I BUS messages for the Instrument Cluster:
l Post “Brake Fluid Level ”in the Message centre
l Notify the ABS via CAN that the Fluid level has been low for more than 25 seconds.
The ABS ECU immediately switches DSC functions off and continuously illuminates the DSC indicator in the cluster.
DSC System Warning Lamps
Instrument Pack Warning Lamps
1 HDC lamp
2 Brake warning lamp
3 Brake assist /brake warning lamp
4 ABS warning lamp
5 DSC warning / information lamp
M70 1184
1/2
1/1
30
110
130
150
10
90
90
50
70
5
4
3
1
2
BRAKES
DESCRIPTION AND OPERATION 70-23
The following table describes the warning lamps, their associated faults and system response.
ABS Modulator
The ABS modulator controls the supply of hydraulic pressure to the brakes in response to inputs from the ABS ECU.
The modulator is attached by three mounting bushes to a bracket on the LH inner wing, and connected to the primary
and secondary hydraulic circuits downstream of the master cylinder assembly. Two electrical connectors link the ABS
modulator to the vehicle wiring. Internal passages in the ABS modulator, separated into primary and secondary
circuits, connect to the various components that control the supply of hydraulic pressure to the brakes. Valves and
check valves control the flow through the internal circuits. A damper chamber and restrictor are included in each circuit
to refine system operation. Inlet and outlet solenoid valves control the flow to the individual brakes. An expansion
chamber is connected to each circuit to absorb pressure. A return pump is connected to both circuits to provide a
pressure source.
System Status Hand Brake
Warning
Lamp
Brake
Warning
Lamp
ABS Lamp DSC Lamp HDC
Lamp
Message Centre
Lamp check On for 2
seconds
Amber for 1
second
then red for
1 second
On for 2
seconds
On for 2
seconds
On for 2
seconds
ECU under voltage On, red
and amber
On On Off
Hand brake On On, red Release park brake
(when driving)
Low brake fluid level On, red Check brake fluid
Electric Brake Assist (EBA)
failure) ABS & EBD available)
On, amber Off
ABS Failure (EBD available) On, amber On On Off
EBD failure On, red On On Off
DSC failure On, amber,
or red
On On Single gong 1st
time failure occurs
HDC failure On, amber
or red
On Off HDC Inactive
DSC activity (including engine
intervention)
flash 2 Hz
ETC activity (brakes only)
DSC switched passive (TC
function still available)
On
ETC activity while DSC switched
passive
On
HDC switched on (not enabled or
fading out)
flash 2 Hz
HDC switched on and enabled On
HDC temporarily unavailable
(brake overheat)
Off HDC temp. Not
available
HDC switching off (due to high
speed in high range)
Off No HDC - slow
down
Driver attempt to switch on HDC
at high speed in high range
Off No HDC - slow
down
BRAKES
70-24 DESCRIPTION AND OPERATION
ABS ECU Harness Connector
ABS ECU Harness Connector C0506 Pin Details
Pin No. Description Input/Output
1Ground –
2 Battery power supply Input
3 Pre-charge pump power supply Output
4 Pre-charge pump ground –
5Ground –
6 Battery power supply Input
7 HDC active signal Output
8 DSC sensor lateral acceleration Input
9 DSC sensor test Output
10 DSC sensor rotation rate Input
11 Diagnostic DS2 bus Input/Output
12 Front LH wheel speed sensor signal Input
13 Rear LH wheel speed sensor reference voltage Output
14 Rear RH wheel speed sensor reference voltage Output
15 Front RH wheel speed sensor reference voltage Output
16 Front RH wheel speed sensor signal Input
17 HDC switch Input
18 Front RH wheel speed Output
19 Rear RH wheel speed Output
20 ABS indicator light Output
21 DSC sensor ground –
22 Not used –
23 Power supply from ECM relay Input
24 CAN bus high Input/Output
25 Brake pressure sensor ground –
26 Brake pressure sensor signal Input
27 DSC switch Input
28 Front LH wheel speed sensor reference voltage Output
29 Rear LH wheel speed sensor signal Input
30 Not used –
31 Rear RH wheel speed sensor signal Input
32 Brake switch Input
33 Not used –
34 Rear LH wheel speed Output
BRAKES
DESCRIPTION AND OPERATION 70-25
35 Front LH wheel speed Output
36 Brake fluid level switch Input
37 and 38 Not used –
39 DSC sensor power supply Output
40 CAN bus low Input/Output
41 DSC sensor rotation rate reference Input
42 Brake pressure sensor reference voltage Output
Pin No. Description Input/Output
BRAKES
70-26 DESCRIPTION AND OPERATION
Operation
ABS Braking Mode
The ABS ECU controls the ABS function of the system in two ways:
1 Engine intervention
2 Braking intervention.
During brake intervention the ABS ECU energizes the inlet and outlet solenoid valves of the related brake and starts
the return pump. The inlet solenoid valve closes to isolate the brake from pressurized fluid; the outlet solenoid valve
opens to release pressure from the brake into the expansion chamber and the return pump circuit. The brake releases
and the wheel begins to accelerate. The ABS ECU then operates the inlet and outlet valves to control the supply of
hydraulic pressure to the brake and apply the maximum braking effort (for the available traction) without locking the
wheel.
Dynamic Stability Control (DSC)
The DSC system is designed to improve the lateral stability of the vehicle in all driving situations.
The DSC system is active unless switched off by the DSC switch in the dashboard. When switched off the DSC
warning lamp is permanently illuminated.
1 DSC switch
DSC optimises dynamic stability, even in critical driving situations. The system controls dynamic stability when
accelerating and when starting from a standstill. Additionally, it identifies unstable driving behaviour, such as under-
steering and over-steering, and helps to keep the vehicle under control by manipulating the engine output and
applying the brakes at individual wheels. Some noise may be generated when the brakes are applied. The system is
ready to operate each time the engine is started.
The indicator lamp in the instrument pack extinguishes shortly after the engine has been started (see earlier section).
If the indicator lamp flashes, the system is active, regulating engine output and brake forces. If the lamp does not
extinguish after starting the engine, or illuminates continuously during a journey, the system has a fault, or has been
de-selected using the switch provided. Without DSC, the vehicle may be driven as normal, but at the limit of adhesion
its behaviour will be less predictable.
BRAKES
DESCRIPTION AND OPERATION 70-27
If the power supply has been interrupted by disconnecting the vehicle's battery, ABS and DSC will be deactivated.
These functions are reactivated by driving a short distance, or by turning the steering wheel from lock to lock while
the vehicle is stationary and the engine is running. Reactivation is indicated by extinguishing of the warning lamps.
ETC is continuously available to boost vehicle traction when one or more wheels has a tendency to spin. It operates
in conjunction with the DSC system. If a wheel is tending to spin, ETC automatically brakes that wheel until it regains
grip and can transmit the engine's power again. This braking activity causes the engine's power to be transferred to
the remaining wheels. Some noise may be generated when the brake is applied to the spinning wheel.
It is possible to de-select the stability control function of DSC, leaving the ETC system active, by pressing the DSC
button. The amber DSC lamp illuminates continuously, to indicate that the stability function is passive. It is
recommended that the DSC system should be temporarily de-selected, in order to maximise forward traction, only in
the following exceptional circumstances:
l If the vehicle needs to be rocked out of a hollow or a soft surface
l Starting in deep snow, or on a loose surface
l Driving in deep sand
l On tracks with deep longitudinal ruts
l Driving through deep mud.
If the DSC button is pressed a second time, the system will be re-selected, and the amber DSC lamp will extinguish.
Electronic Traction Control (ETC)
The ability to control the vehicle while driving, is lost as a result of excessive wheel spin or slip if a tyre exceeds its
ability to:
l Maintain traction
l Accept side forces to maintain directional control
The ETC feature of the DSC on the New Range Rover cannot be switched OFF with the DSC switch. Pressing the
button will only switch off the dynamic stability control function of the DSC.
The traction control feature is needed at all times to provide anti-wheel spin control especially when driving the vehicle
off road. The DSC warning lamp in the instrument cluster will come on when the system is switched off manually or
there is a fault in the system.
Off road traction control or HDC operation places an additional load on the brakes. To prevent overheating of the
brakes and discs, the temperature of the discs is calculated over time from the road speed and amount of brake
application (from the pressure sensor). If the temperature of one or more discs goes above approximately 600°C, the
traction control function for that wheel will be cancelled temporarily. Engine intervention is still active to prevent
spinning of that wheel. Once the temperature of the disc goes below approximately 500°C, the traction application will
be reactivated.
The normal braking function (including ABS) is always active at any temperatures.
Corner Braking Control (CBC)
CBC improves stability control while braking through corners.
As the vehicle enters a corner, the weight of the vehicle shifts to the outside wheels. With non CBC equipped vehicles,
if the driver brakes while driving through a corner an equal hydraulic force is applied to each wheel. Though the
pressure is equal the grip available for braking is unequal at the tyre footprint due to the increased weight on the
outside wheels.
With a CBC equipped vehicle, the feature regulates the applied pressure to the wheels based on the rate of cornering.
When the driver brakes, an unequal hydraulic pressure is applied to each side of the vehicle. Though the brake
application pressure to each wheel is unequal, the dynamic of the vehicles weight transfer compensates for the
unequal pressure, as a result braking effort is distributed in proportion to the grip available ensuring that lateral grip
is maintained.
BRAKES
70-28 DESCRIPTION AND OPERATION
Electronic Brake Distribution (EBD)
Electronic brake proportioning allows the DSC system to adjust the braking force to the rear wheels based on the
vehicles loading to maximize the braking force at all wheels.
The ABS control module monitors the wheel speed sensors inputs when the brakes are applied, for activation of this
feature. The control module compares the speed at which the front and rear axles are slowing down to determine
vehicle loading.
If the rear axle is slowing at a similar rate to the front, it indicates that the vehicle is loaded and braking force need not
be limited to the rear axle.
If the deceleration of the rear axle is greater than the front, the vehicle is lightly laden and less force can be applied
to the rear. If the same force were applied, then the vehicle could become unstable.
The values for the relative deceleration are programmed in the ABS ECU. Equal force will be applied to the front and
rear axles until the threshold values are exceeded. At this point, the ABS ECU will cycle the inlet valves at the rear
calipers to limit or reduce the braking force on the rear axle.
Emergency Brake Assist (EBA)
The EBA is designed to enhance the braking control of the DSC for the driver of the vehicle. The EBA includes two
functions that are programmed into the control electronics of the ABS ECU with no additional hardware changes.
The first EBA function is designed to provide the maximum braking force available during rapid (panic) braking
situations. The ABS control module looks at the inputs from the brake pedal switch and the signal from the brake
pressure sensor on the master cylinder. The criteria for activation of EBA is the speed at which brake pressure builds
up with the brake pedal depressed. The total criteria required for EBA activation includes:
l Brake switch ON
l Brake pressure build up >threshold value
l Vehicle road speed >5mph (8 km/h)
l Vehicle not in reverse
l Not all wheels in ABS operation.
If the threshold for EBA activation is achieved, the ABS control module will activate a pressure build up regulation
phase through the hydraulic unit. The pressure at all wheels is increased up to the ABS operation point. This occurs
even if the driver does not achieve the ABS operation point with the pedal.
The front and rear axle brakes are controlled individually. ABS operation will continue until the driver releases the
pedal and the pressure in the master cylinder drops below the threshold value stored in the ABS ECU.
The second EBA function is also designed to enhance a driver initiated braking procedure. The EBA will build up the
pressure in the rear brake circuit when the front brakes are already in an ABS regulation cycle. The additional braking
pressure at the rear wheels will shorten the stopping distance. The following criteria must be met before the ABS
control module will activate EBA:
l Both front wheel brakes in ABS operation
l Vehicle speed >5mph (8km/h)
l Vehicle not in reverse
l EBA and pressure sensor initialisation test OK
l Rear wheels not in ABS operation.
EBA sensitivity can be adjusted using TestBook/T4. There are three sensitivity settings, default is the most sensitive.
Hill Descent Control (HDC)
Hill Decent Control (HDC) is designed for off road use to automatically slow the vehicle and maintain a steady speed
on steep gradients. This function allows the driver to focus on steering and controlling the vehicle without having to
use the brakes to slow the vehicle.
BRAKES
DESCRIPTION AND OPERATION 70-29
1 HDC switch
HDC is activated manually through the switch located in the centre console next to the transmission gear selector.
HDC can be selected under any conditions while low range is selected, and below the 21 mph (35 km/h) speed
threshold when high range is selected. The HDC Lamp in the instrument pack indicates HDC selection status. If
enable conditions are not met, system goes in to stand by mode. When activated, the vehicles speed is held to
approximately 5 MPH (3 km/h) by the DSC ECU pulsing the brakes to maintain the speed.
The following conditions must be met before the HDC will activate:
l HDC switch operated -LED “ON “
l Vehicle speed:<21 MPH (35 km/h)
l Accelerator pedal pressed <15%
l Downhill driving recognised.
If the HDC switch is operated above 21 mph (35 km/h) in high range, "NO HDC - SLOW DOWN" message will be
displayed in the instrument pack, and HDC will not be selected.
If the HDC switch is held down for more than 10 seconds, the HDC selection status does not change
If HDC is selected, then vehicle ignition switched off, the HDC selection status remains in the ABS ECU memory for
6 hours. If the vehicle is restarted within this time, HDC remains selected. If vehicle is not started within this time HDC
will be automatically de-selected. If the vehicle speed exceeds 37 mph (60 km/h) while high range is selected, HDC
is automatically de-selected.
BRAKES
70-30 DESCRIPTION AND OPERATION
Hill Descent Control Enable Criteria
The target speed used by the HDC varies in response to driver inputs. Current target speed will lie in the range
between Maximum Target Speed and Minimum Target Speed.
Hill Descent Control Target Speeds
When HDC is first activated, if the driver does not press the brake or accelerator pedals, then current target speed is
set to default target speed. If HDC is activated and the driver presses the brake pedal, the vehicle brakes operate as
normal. While the brake pedal is pressed:
l If vehicle speed is equal to or more than current target speed, current target speed is unchanged
l If vehicle speed is less than current target speed, current target speed is set to vehicle speed
When the brake pedal is released:
l If vehicle speed is equal to or more than minimum target speed, then current target speed is unchanged
l If vehicle speed is less than minimum target speed, then Current Target Speed is set to minimum target speed.
If HDC is activated and the driver presses the accelerator pedal, current target speed is defined by a characteristic as
follows:
l If current target speed is less then default target speed, then the target speed is set to current speed.
When the accelerator pedal is released:
l If current target speed is greater than default target speed and vehicle speed is equal to or more than default
target speed, then current target speed is set to default target speed
l If current target speed is more than default target speed and vehicle speed is less than default target speed,
then current target speed is set to vehicle speed
l If current target speed is less than or equal to default target speed, and vehicle speed is less than current target
speed , then current target speed is set to vehicle speed
l If current target speed is less than or equal to default target speed , and vehicle speed is equal to or more than
current target speed , then current target speed is unchanged.
To ensure that the vehicle is in an appropriate gear during HDC activity the ABS ECU communicates with the EAT
ECU. A unique gearbox map is activated when HDC braking activity begins. The characteristics of the map are that
lower gears are selected sooner than normal, and higher gears are selected later than normal. This reduces the work
done by the foundation brakes, and improves the response time of HDC.
Fade-Out Mode
Fade-out and system switch off is triggered by the following:
l Driver de-selection
l System failure.
Gear Detected Neutral Auto Transmission D, 1-5, R
Throttle less
than 5%
Enabled Enabled
5% to 20% Stand by Enabled
Throttle more
than 20%
Stand by Stand by
Low High
Gear
selector
position
D12345RN
D,1,2,3,4,5
RN
Maximum
target
speed
35 km/h
(22 mph)
35 km/h
(22 mph)
35 km/h
(22 mph)
35 km/h
(22 mph)
35 km/h
(22 mph)
35 km/h
(22 mph)
35 km/h
(22 mph)
— 35 km/h
(22 mph)
35 km/h
(22 mph)
—
Standard
target
speed
6 km/h
(4 mph)
3.5 km/h
(2 mph)
6 km/h
(4 mph)
6 km/h
(4 mph)
6 km/h
(4 mph)
6 km/h
(4 mph)
3.5 km/h
(2 mph)
6 km/h
(4 mph)
10 km/
(6 mph)
6 km/h
(4 mph)
10 km/h
(6 mph)
Minimum
target
speed
3.5 km/h
(2 mph)
3.5 km/h
(2 mph)
3.5 km/h
(2 mph)
3.5 km/h
(2 mph)
3.5 km/h
(2 mph)
3.5 km/h
(2 mph)
3.5 km/h
(2 mph)
6 km/h
(4 mph)
6 km/h
(4 mph)
6 km/h
(4 mph)
BRAKES
DESCRIPTION AND OPERATION 70-31
Fade-out and system stand by mode is triggered by the following:
l Throttle pedal pressed in neutral
l Brake overheat.
By gradual reduction of brake pressure, the vehicle is allowed to accelerate at a maximum rate of 0.5 m/s
2
until
maximum target speed is reached, or until no active pressure in system for 0.5 sec. The system then switches off, or
into stand by mode, depending on the trigger for fade-out mode.
If the throttle pedal is pressed less than 20% (parameter), fade-out acceleration limited to 1 m/s
2
. If the throttle pedal
is pressed 20% or more, system switches off, or into stand by mode, depending on the trigger for fade-out mode.
Off-Road ABS Control Module Programming
The programming for ABS regulation allows a higher threshold for ABS regulation when driving off-road in loose
gravel or dirt. A locked wheel is more effective in slowing or stopping the vehicle because of the wedge that is built
up in front of the tyre.
The programming in the ABS control module allows one or both front wheel(s) to lock up at low speeds on a rough
road as long as the vehicle is travelling straight ahead. If the ABS ECU receives a signal from the steering angle
sensor indicating a turn, ABS regulation will activate to prevent the lock and allow the vehicle to be steered.
BRAKES
70-32 DESCRIPTION AND OPERATION
DESCRIPTION AND OPERATION
Hand Brake Component Location
BRAKES
DESCRIPTION AND OPERATION 70-33
1 Hand brake lever
2 Ratchet mechanism (internal)
3 Rear brake
4 Hand brake cable
5 Hand brake cable inner cable connection
6 Cable divider
7 Brake lamp switch
8 Hand brake cable
9 Return spring
10 Brake shoe
11 Brake shoe retainer spring
12 Brake shoe retainer
13 Rear brake shoe adjuster
14 Hand brake shoe expander
15 Expander return shoe spring
16 Hand brake cable to trailing arm grommet
17 Hand brake cable mounting bracket
18 Bolt
19 Hand brake cable to body clip
BRAKES
70-34 DESCRIPTION AND OPERATION
Hand Brake
Introduction
The parking brake system utilised on the New Range Rover is a new application on Land Rover vehicles. The
characteristics of the system are significantly different to the transmission brake based system that is currently fitted
to most Land Rover vehicles.
Description
The handbrake lever is a clenched two-shell construction incorporating an automatic cable adjuster. The handbrake
cables are actuated via an equaliser and a cable centrally mounted within the lever, which is in turn attached to one
half of the spring loaded adjuster
The design of this hand brake incorporates an automatic adjuster which eliminates the need for warranty adjustments.
The two-shell design allows automatic assembly of the internal components.
The hand brake cable is centrally mounted within the lever as a significant offset of the cable causes the lever to rotate
sideways under the high cable loads required. This construction means that the part of the bracket that supports the
lever pivot must be moved outside the lever rather than having the conventional inboard position. The lever is high
mounted to suit the 'Command' driving position, on a secondary - mounting bracket, which also allows the assembly
of necessary components under the handbrake.
Function
When the lever is in the rest position, the adjuster opener holds the adjuster open. In this position, the lever is
effectively disconnected from the handbrake cable. This allows the adjuster spring, if required, to remove slack in the
handbrake cables. After less than 5 degrees of lever travel and normally before the first tooth is engaged, the adjuster
is closed and the cables and hence the parking brakes are actuated. No adjustment of the cables is required during
assembly or by the dealer. The function of the adjuster is to remove slack in the handbrake cables and not to provide
any adjustment of the parking brake itself. The adjuster spring force is always lower than the brake shoe return spring
force.
Performance
In order to achieve the required performance targets, the lever ratio is relatively high at 7.25:1. Also, in comparison to
Range Rover, fine ratchet teeth are employed for the convenience of slighter drivers. The overall performance of the
system is totally dependent on the correct adjustment and bedding of the Duo-Servo parking brake. The adjuster
travel is 25-30 mm, in other words in the worst tolerance condition the system can compensate for 25mm of slack in
the cable system. Slack in the system can be caused by both initial tolerance stack-up in the body / parking brake
system and actual 'stretch' in the system.
Replacement
The handbrake is supplied with a pin in position that locks the adjuster spring in the fully compressed condition. This
allows the handbrake to be raised to the fully up position with the cables connected, in order to facilitate the assembly
of the centre console. Subsequent to the assembly of the centre console, the pin can be removed and the lever
lowered, at which point the adjuster will provide the required cable tension.
A mounting clip is provided, which is clipped to the equaliser and fitted over the ends of the body tubes, in order to
provide location whilst the cables are fed through the body tubes and into the 'quick fit' connections in the equaliser.
This allows a 'one man' operation for cable fitment.
BRAKES
DESCRIPTION AND OPERATION 70-35
System Specifications
Service
The servicing requirements for the handbrake lever and cable system are minimal. However, the handbrake cables
remain a serviceable item and will need to be periodically replaced. The cables will always be in tension due to the
automatic adjuster and this tension must be released in order to facilitate replacement. The process to achieve this is
as follows:
1 Lower handbrake to rest position
2 Release gaiter from centre console and roll back to expose lever assembly
3 Remove access panel from rear of centre console
4 Pull back equaliser until adjuster spring is fully compressed
5 Replace pin. A suitably sized pin of adequate strength (preferably steel) may be used
6 Replace cables
7 Remove pin. The pin may be removed with the handbrake in any position
8 Replace gaiter and rear access panel.
Lever Ratio 7.25 : 1
Max Travel 38°
Max No of Teeth on Ratchet 16
Max cable travel 20 mm
Max Adjuster Travel 20 mm
BRAKES
70-36 DESCRIPTION AND OPERATION
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-1
RESTRAINT SYSTEMSDESCRIPTION AND OPERATION
Front Seat Belts
1 Height adjuster
2 Buckle
3 Anchor point
4 Inertia reel
RESTRAINT SYSTEMS
75-2 DESCRIPTION AND OPERATION
Rear Seat Belts
1 Inertia reel
2 Anchor point
3 LH outer belt buckle
4 RH outer and centre belt buckles
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-3
SRS Component Layout – Sheet 1 of 2
1 Front head airbag
2 Rear head airbag
3 Side airbag
4 Pretensioner
5 Side impact sensor
6 Battery disconnection unit
RESTRAINT SYSTEMS
75-4 DESCRIPTION AND OPERATION
SRS Component Layout – Sheet 2 of 2
1 Seat occupancy module
2 Passenger airbag
3 Airbag warning lamp
4 Driver airbag
5 DCU
6 Seat occupancy sensor
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-5
Description
General
Restraints consist of seat belts at each seat position and a Supplementary Restraint System (SRS) in the form of
airbags and seat belt pretensioners.
Seat Belts
The seat belts are all three point inertia reel belts. The front seat belts incorporate load limiters and have height
adjusters on the B/C post. The outer rear seat belts have height adjusters on the D post.
On NAS vehicles, all passenger seat belts are the Automatic Locking Retractor (ALR) type for use with child restraint
systems.
A seat belt warning lamp and associated message are activated on the instrument pack, by the Light Check Module
(LCM), at the beginning of each ignition cycle as a reminder to fasten seat belts.
ISO child seat fixings are installed on the back of each outer rear seat.
SRS
The SRS activates pretensioners and/or airbags if the vehicle suffers an impact above preset limits. When it activates
the pretensioners/airbags the SRS also disconnects the starter lead from the battery. The SRS consists of:
l A Diagnostic Control Unit
l Two side impact sensors
l A seat occupancy sensor
l A seat occupancy module
l Seat belt switches
l Seat belt pretensioners
l A driver airbag
l A passenger airbag
l Side airbags
l Front head airbags
l Rear head airbags
l A battery disconnect unit
l The rotary coupler
l A warning lamp.
The SRS features selective activation of the airbags and pretensioners, and two stage driver and passenger airbags.
The driver and passenger airbags each have two gas generators which are fired sequentially, with a variable time
delay between firings to adjust the speed of airbag inflation to the severity of the crash impact.
RESTRAINT SYSTEMS
75-6 DESCRIPTION AND OPERATION
DCU
The DCU is installed on the top of the transmission tunnel, alongside the handbrake, and controls the operation of the
SRS. The main functions of the DCU include:
l Crash detection and recording
l Airbag and pretensioner firing
l Self test and system monitoring, with status indication via the warning lamp and non-volatile storage of fault
information.
Accelerometers in the DCU provide crash detection for front and rear impacts. A safing sensor provides confirmation
of a frontal impact. Various firing strategies are employed by the DCU to ensure the airbags/pretensioners that are
fired are appropriate to the severity and direction of the impact. The firing strategy used also depends on the inputs
from the seat belt buckle switches and the occupancy detector sensor, and varies between NAS and other markets.
An energy reserve in the DCU ensures the firing signals can be produced for a minimum of 150 milliseconds after a
crash is detected, in case of disruption to the system power supply from the ignition switch.
When the ignition is switched on the DCU performs a self test and then performs cyclical monitoring of the system. If
a fault is detected the DCU stores a related fault code in memory and illuminates the SRS warning lamp. Faults can
be retrieved by TestBook/T4 from the DCU via the K bus connection with the instrument pack. If a fault that could
cause a false fire signal is detected, the DCU actively disables the respective firing circuit, and keeps it disabled during
a crash event.
SRS DCU Harness Connector
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-7
SRS DCU Harness Connector C0256 Pin Details
Pin No. Description Input/Output
1 RH front seat belt pretensioner positive Output
2 RH front seat belt pretensioner negative Input
3 LH front seat belt pretensioner negative Input
4 LH front seat belt pretensioner positive Output
5 Auxiliary power Input
7 SRS warning lamp Output
8 Front passenger seat belt buckle switch (where fitted) Input
9 K bus Input/Output
10 Driver airbag squib 1 positive Output
11 Driver airbag squib 1 negative Input
12 Driver seat belt buckle switch Input
13 Passenger airbag squib 1 negative Input
14 Passenger airbag squib 1 positive Output
15 Seat occupancy detection Input
16 LH side airbag negative Input
17 LH side airbag positive Output
18 RH side airbag positive Output
19 RH side airbag positive Input
20 LH side impact sensor Input
21 RH side impact sensor Input
22 to 25 Not used –
26 Driver airbag squib 2 negative Input
27 Driver airbag squib 2 positive Output
28 LH rear head airbag negative Input
29 LH rear head airbag positive Output
30 to 32 Not used –
33 Passenger airbag squib 2 positive Output
34 Crash signal Output
35 to 39 Not used –
40 Passenger airbag squib 2 negative Input
41 RH rear head airbag negative Input
42 RH rear head airbag positive Output
43 and 44 Not used –
45 LH front head airbag negative Input
46 LH front head airbag positive Output
47 RH front head airbag positive Output
48 LH front head airbag positive Input
49 Battery disconnect unit negative Input
50 Battery disconnect unit positive Output
51 to 75 Not used –
RESTRAINT SYSTEMS
75-8 DESCRIPTION AND OPERATION
Side Impact Sensor
A side impact sensor is installed in each B/C post and connected to the DCU. The use of independent side impact
sensors provides shorter airbag triggering times, through faster detection of lateral acceleration, and improves
detection accuracy.
Each side impact sensor incorporates an accelerometer and a microcontroller powered by a feed from the DCU. The
power feed also provides the interface connection through which the side impact sensor communicates with the DCU
using serial data messages. Lateral acceleration is evaluated by the microcontroller and transmitted to the DCU,
which then makes the decision on whether or not to activate the side and head airbags.
When the ignition is switched on the DCU supplies power to the side impacts sensors, which perform a self test. After
satisfactory self tests the side impact sensors continually output 'sensor active' messages to the DCU. If a fault is
detected the relevant side impact sensor sends a fault message, instead of the sensor active message, to the DCU,
which stores a related fault code in memory and illuminates the SRS warning lamp. Faults can be retrieved by
TestBook/T4 from the DCU via the K bus connection with the instrument pack.
Seat Occupancy Sensor
The seat occupancy sensor is installed in the cushion of the front passenger seat between the foam padding and the
cover. The sensor consists of a foil contact circuit, embedded in a plastic sheet. Weight on the sensor reduces the
resistance of the circuit.
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-9
Seat Occupancy Module
The seat occupancy module is installed on the underside of the front passenger seat. The module supplies a power
feed to the seat occupancy sensor and monitors the return voltage to determine if the seat is occupied or not. The
result is transmitted to the DCU as a serial data message. The seat occupancy module also monitors for short and
open circuits in the seat occupancy sensor. If it detects a fault, the seat occupancy module transmits a fault message
to the DCU in place of the status message.
Seat Belt Switches
A seat belt switch is installed in the buckle of each front seat belt (NAS only) or only in the buckle of the driver's seat
belt (all except NAS) to provide the DCU with a status signal of the related seat belt(s). When the seat belt is
unfastened the switch is open circuit. When the seat belt is fastened the switch is closed and connects a battery power
signal to the DCU.
RESTRAINT SYSTEMS
75-10 DESCRIPTION AND OPERATION
Pretensioner
1 Seat belt buckle
2 Electrical connector
3 Piston
4 Piston housing
5 Direction of piston travel
6 Expanding gas
7 Squib/Gas generator
8 Steel cable
9 Gaiter
The pretensioners are used to tighten the front seat belts during a collision to ensure the occupants are securely held
in their seats. A pretensioner is integrated into each front seat belt buckle and attached to a bracket on the inboard
side of the seat.
Each pre-tensioner has a tube containing propellant and a piston. The piston is attached to a steel cable, the opposite
end of which is attached to the seat belt buckle. A squib in the base of the tube provides an ignition source when
triggered by a fire signal from the DCU.
On receipt of a fire signal from the DCU, the squib ignites the propellant. The propellant produces nitrogen gas that
rapidly expands to drive the piston along the tube, pulling the cable and drawing the buckle downwards.
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-11
Driver Airbag
1 Cover
2 Electrical connector
3 Housing
4 Securing pins
5 Etched lines
The driver airbag is integrated into the centre pad of the steering wheel and held in place by two securing pins that
locate in latches on the steering wheel boss.
The airbag unit has two gas generators installed side by side, with separate electrical connectors attached to the squib
of each gas generator.
Lines etched into the inner surface of the cover provide weak points that split open in a controlled manner when the
airbag deploys.
RESTRAINT SYSTEMS
75-12 DESCRIPTION AND OPERATION
Passenger Airbag
1 Securing flange
2 Airbag
3 Housing
4 Electrical connector
The passenger airbag module is installed in the fascia above the glovebox.
The airbag unit has a gas generator installed at each end with separate electrical connectors attached to the squib of
each gas generator.
A hinged deployment door is etched into the inner surface of the fascia trim panel that covers the airbag.
Passenger Airbag Deployment
1 Airbag 2 Deployment door
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-13
Side Airbag
1 Securing lug
2 Airbag cover
3 Perforated break lines
4 Electrical connector
A side airbag is installed behind the trim panel of each front door. An electrical connector links the squib in the airbag
to the DCU. The airbag is contained in a metal housing closed by a plastic cover. Perforated lines in the cover, and
etched lines in the door trim panel, provide weak points that split open in a controlled manner when the airbag deploys.
When the airbag deploys it covers the adjacent areas of the door above and to the rear of the airbag module.
Side Airbag Deployment
1 Deployment flap
2 Tether strap
3 Airbag
RESTRAINT SYSTEMS
75-14 DESCRIPTION AND OPERATION
Front Head Airbag
1 Electrical connector
2 Inflation tube
3 Retaining clip
4 Airbag
5 Rear tether strap
6 Front tether strap
7 Gas generator
The front head airbags are installed behind the A post trim and above the outer edges of the headlining. The inflatable
bag incorporates tether straps at each end which are attached to the body. When the airbag deploys, the inflating bag
shortens in length and pulls on the tether straps, which forces it from behind the trim to cover the window in a straight
line between the tether strap anchor points.
Rear Head Airbag
1 Housing
2 Gas generator
3 Electrical connector
4 Securing bracket
5 Deployment flap
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-15
The rear head airbags are installed behind the outer edges of the headlining above the D post. When the airbag
deploys, the inflating bag forces itself from behind the trim to cover the upper part of the D post and adjacent areas
of the rear door and quarter light.
Battery Disconnect Unit
The battery disconnect unit is attached to the positive terminal on the battery and allows the DCU to disconnect the
main starter cable during a crash.
The battery disconnect unit incorporates the positive terminal connector and heavy duty cables for the starter and for
engine and passenger compartment power distribution. The starter cable connection is contained in a plastic housing
next to the battery terminal. The end fitting of the starter cable is a tapered press fit in one end of a gas discharge
tube. The other end of the gas discharge tube contains a gas generator and a squib connected to the DCU.
When the DCU fires the squib, the gas from the gas generator forces the end fitting of the starter cable out of the gas
discharge tube and breaks the connection with the starter motor. As the end fitting is pushed out of the gas discharge
tube, spring tabs in the plastic housing engage with the rim of the end fitting to hold it clear of the gas discharge tube.
The fuel pump motor is shut off by the relevant ECM after the ECM receives a crash signal from the SRS DCU. See
relevant engine management sections for more detail.
1 Battery terminal connector
2 Electrical connector
3 Gas generator
4 Gas discharge tube
5 Spring tab
6 Starter cable
7 Power distribution cable
8 View after firing
M76 4543
21
34
5
6
7
8
RESTRAINT SYSTEMS
75-16 DESCRIPTION AND OPERATION
Rotary Coupler
1 Outer housing
2 Electrical connector
3 Inner housing
4 Drive spigot
5 Locking lever
6 Electrical connector
The rotary coupler is installed on the steering column to provide the electrical interface between the fixed wiring
harness and the steering wheel. The rotary coupler provides connections for the driver airbag, horn and steering
wheel switch packs.
A rotating link harness is encapsulated into a plastic cassette comprising outer and inner housings with integral
connectors. Brackets on the outer housing accommodate the column stalk switches. A spring loaded locking lever
attached to the outer housing automatically engages and disengages with the inner housing when the steering wheel
is removed and installed. To prevent damage to the rotating link harness, both the steering and the rotary coupler
must be centralised when removing and installing the steering wheel.
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-17
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DESCRIPTION AND OPERATION
RESTRAINT SYSTEMS
75-18 DESCRIPTION AND OPERATION
SRS Control Diagram
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus
M76 4464A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
A
B
C
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-19
1 Ignition switch
2 Occupancy detection sensor
3 Driver airbag
4 Rotary coupler
5 Passenger airbag
6 Battery disconnection unit
7 BCU
8 Instrument pack
9 Diagnostic socket
10 RH side airbag
11 LH side airbag
12 RH front head airbag
13 RH rear head airbag
14 LH front head airbag
15 LH rear head airbag
16 DCU
17 RH side impact sensor
18 LH side impact sensor
19 Driver pretensioner
20 Passenger pretensioner
21 Occupancy detection unit
22 Fuse 14, passenger compartment fusebox
RESTRAINT SYSTEMS
75-20 DESCRIPTION AND OPERATION
Operation
SRS
In a collision the sudden deceleration or acceleration is measured by the side impact sensors and the crash sensors
in the DCU. The DCU evaluates the readings to determine the impact point on the vehicle and whether the
deceleration/acceleration readings exceed the limits for firing the airbags, the pretensioners and the battery
disconnect unit. The DCU incorporates the following limits to cater for impacts of varying severity and at different
points on the vehicle:
l Pretensioner
l Driver and passenger airbag 1
l Driver and passenger airbag 2
l Driver and passenger airbag 3
l Driver and passenger airbag 4
l Rear impact
l Battery disconnect unit
l LH side and head airbags
l RH side and head airbags.
Firing Strategies
The seat belt pretensioners are fired when either the pretensioner or the rear impact limit is exceeded. In a frontal
impact, the DCU only fires the pretensioners if the safing sensor has closed, and also evaluates the inputs from the
seat belt switches and the seat occupancy module before it comes to a firing decision.
The driver and passenger airbags are fired in a frontal impact. The time delay between firing the two gas generators
in each airbag decreases with the increasing severity of the impact, until, at the most severe impact limit (driver and
passenger airbag 4), the gas generators are fired simultaneously. In a frontal impact, the DCU only fires the driver
and passenger airbags if the safing sensor has closed, and also evaluates the inputs from the seat belt switches and
the seat occupancy module before it comes to a firing decision.
If there is a fault with a seat belt switch input, the DCU assumes the seat belt is fastened for the pretensioner firing
strategy and unfastened for the airbag firing strategy. If there is a fault with the occupancy detection sensor, the DCU
assumes the front passenger seat is occupied.
Front and Rear Impact Firing Strategy
Seat Belt Status Passenger
Seat Status
Strategy
Driver Passenger Pretensioner Driver Airbag Passenger Airbag
Fastened ––Fired at pretensioner or
rear impact limit
Fired at limit 2 or above –
Unfastened –– Not fired NAS: Fired at limit 1 or
above
All except NAS: Fired
at limit 2 or above
–
– Fastened Occupied Fired at pretensioner or
rear impact limit
– Fired at limit 2 or above
Unoccupied Fired at pretensioner or
rear impact limit
– Not fired
– Unfastened Occupied Not fired – NAS: Fired at limit 1 or
above
All except NAS: Fired
at limit 2 or above
Unoccupied Not fired – Not fired
RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-21
The battery disconnect unit is fired:
l At driver and passenger airbag limit 2 in a frontal impact
l At the battery disconnect unit limit in a side impact
l At the rear impact limit in a rear impact.
If one of the side impact limits is exceeded the DCU fires the side airbag and the head airbag(s) on that side of the
vehicle. If the side impact limit on the front passenger side of the vehicle is exceeded, the DCU also evaluates the
input from the seat occupancy module, and fires only the head airbag(s) if the front passenger seat is unoccupied.
In a roll-over, the airbags, pretensioners and battery disconnect unit are only fired if a related impact limit is exceeded.
If multiple impacts occur during a crash event, after responding to the primary impact the DCU will output fire signals
in response to secondary and further impacts if unfired units are available.
Crash Signal
When the DCU outputs any of the fire signals it also outputs a crash signal to the Body Control Unit (BCU) and the
ECM. On receipt of the crash signal, the BCU goes into a crash mode and the ECM cuts the power supply to the fuel
pump relay. In the crash mode, the BCU:
l Activates all of the unlock signals of the vehicle locking system, even if the vehicle is already unlocked
l Ignores all locking/superlocking inputs until it receives an unlock input, when it returns the locking system to
normal operation
l Activates the interior lamps. The interior lamps remain on permanently until they are manually switched off at the
lamp unit, or the BCU crash mode is switched off and they return to normal operation
l Disables the rear window child lock input until the crash mode is switched off
l Sends a crash message to the Light Check Module (LCM), via the K bus, instrument pack and I bus, to activate
the hazard warning lamps. The hazard warning lamps remain on until cancelled by the hazard warning switch or
the crash mode is switched off.
The BCU crash mode is switched off by a valid locking and unlocking cycle of the locking system.
Component Replacement
After a crash event in which any of the SRS components have been deployed:
l The deployed components and the DCU must be replaced.
l If a side and/or head airbag has been deployed, the side impact sensor on that side of the vehicle must also be
replaced.
l The SRS harness must be examined and replaced if damaged.
RESTRAINT SYSTEMS
75-22 DESCRIPTION AND OPERATION
DOORS
DESCRIPTION AND OPERATION 76-1-1
DOORSDESCRIPTION AND OPERATION
Front Door
DOORS
76-1-2 DESCRIPTION AND OPERATION
Doors
General
The door structure and skins are manufactured from aluminium alloy and are fitted with an impact resistant plastic
panel, finished in the body colour scheme, bolted to the lower external door skins.
The doors are attached to the door posts by two hinges. A door brake, with a metal retaining strap, is fitted between
the door and body frame to restrict the angle that the doors open.
Structurally, the difference between the front and rear doors is the extruded aluminium alloy Side Impact Protection
bar fitted to the front doors. The rear doors have, in addition to the window, a fixed quarter light.
The external door handles are bolted to the door structure and are accessed by removing the door trim casing. The
rear doors are each fitted with a manually operated child protection safety lock.
Child Protection Safety Lock
Fitted within the door structure, is the window regulator and glass, door locking mechanism , door wiring harness and
speakers. A moulded foam sound insulation panel, secured with a non-curing sealant, is fitted between the inner door
skin and trim casing. Between the door actuator and lock is a bowden cable, protected by an insulated sleeve. The
audio system, electric windows and door locking system are serviced by an electric wiring harness.
Trim Casing
The trim finish is dependent on the vehicle option level, either colour matched to the vehicle interior trim or leather
finished.
The trim casings are secured by screws and retaining studs. A moulded sound insulation panel is attached to the door
internal structure with a non-curing sealant.
All four doors have speaker grilles integral with the door trim, a switch to operate the door window mechanism, a
recessed sill lock button, arm rest and door handle.
The driver's door trim casing is fitted with a switch pack linked to the Body Control Unit (BCU) via the P-Bus. This
controls all four windows, and includes an isolation switch for the rear door windows, the door mirrors and the central
locking system.
In addition to the side protection bars, to protect the front seat occupants, a side impact air bag is stowed in the front
trim casings.
+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description.
M76 4549A
DOORS
DESCRIPTION AND OPERATION 76-1-3
Door Locking
Controlled by the BCU, the Central Door Locking (CDL) system controls the door locks.
The CDL system for each door consists of :
l Door lock
l Actuator
l Recessed sill lock button.
The CDL system is operated by the remote handset externally from the driver's door lock or from the CDL switch
positioned on the fascia below the hazard warning switch. A safety feature prevents the doors from opening when a
set vehicle speed is exceeded (10 mph/16 kph).
NOTE: The operation of the door locks by any other means (for example the interior locking switch on the fascia panel)
will unlock the doors.
Single point entry is a security feature that enables the driver's door only to be unlocked using the remote handset or
key. By pressing the remote handset button once, or turning the key towards the front of the vehicle, the driver's door
only unlocks. By pressing the button on the remote handset or turning the key a second time, all the doors are
unlocked.
If the vehicle is unlocked using a single point entry, and if the CDL switch on the fascia is pressed, the driver's door
will relock. Pressing the CDL switch a second time unlocks all the doors.
+ SECURITY, DESCRIPTION AND OPERATION, Description.
Door Mirrors
The external folding mirrors, bolted to the front door structure, are supplied with the following features:
l Driver's door — plane mirror glass
l Passenger door — convex mirror glass
l Electric adjustment
l Mirror heating
l Electrochromic mirror (optional extra)
l Mirror memory and automatic kerb facility (optional extra)
l Folding function (Japan only/optional extra)
l Entrance lighting (optional extra).
Control of the external mirrors is by the BCU. Each mirror is connected to it's door module via a link harness.
Door Module Harness Connectors C2271 LH and RH Pin Details
Pin No. Description Input/Output
1 Mirror horizontal adjustment motor Output
2 Mirror vertical potentiometer Input
3 Mirror fold motor in Output
4 Mirror disengaged microswitch Input
5 Mirror potentiometer power supply Output
6 Mirror potentiometer ground –
7 Mirror heating element Output
8 Mirror horizontal potentiometer Input
9 Mirror vertical adjustment motor Output
10 Mirror fold motor out Output
11 Mirror adjustment motors directional bridge Output
12 Mirror disengaged microswitch ground Output
DOORS
76-1-4 DESCRIPTION AND OPERATION
Door Mirror Harness Connectors C0352 and C0353 Pin Details
Operation
1 Mirror adjustment multi-directional switch 2 LH/RH mirror selection switch
The door mirrors are selected by moving the mirror selection switch. Moving the switch to the left allows LH door mirror
adjustment. Moving the switch to the right allows adjustment of the RH door mirror.
Movement of the mirror glass in the horizontal and vertical axis is by a dual-motor drive operated by the mirror
adjustment multi-directional switch.
There is a maximum adjustment operating time of 10 secs.
Mirror Memory
Available as optional equipment, the seat, mirror and steering column memory functions are integrated in the BCU.
The driver's and front passenger door modules control the mirror memory while the “Seat Memory” peripheral module
controls the seat and steering column memory.
Located on the outboard side of the driver's seat plinth, the memory switch and memory pre-set buttons can store
three different mirror positions. When a position is stored or recalled, the information is transmitted to the BCU via the
K-bus. It is then relayed to the switching centres via the P-bus. Each switching centre evaluates the recalling and
storage commands transmitted via the P-bus for positions 1 to 3 and performs the necessary adjustments.
If a manual adjustment is selected while the mirror memory is operating, it will over-ride the memory recall function.
For mirror memory to operate, the mirror adjustment potentiometers must deliver a voltage value in the range from
80mV - 4.8V. Should a voltage applied be outside of this range the mirror will not operate when memory is selected.
Pin No. Description Input/Output
1 Electrochromic element Input
2 Electrochromic element Input
3 Approach lamp ground –
4 Approach lamp power supply Input
M76 4551
2
1
DOORS
DESCRIPTION AND OPERATION 76-1-5
Automatic Mirror Tilting (Kerb View)
If reverse gear is selected when the ignition is at position I or II, the passenger door mirror dips to provide a better
view of the kerb. The mirror returns to it's original position immediately reverse gear is disengaged.
The kerb view mirror position can be adjusted using the mirror adjustment multi-directional switch when reverse gear
is selected and the ignition is at position I or II.
Mirror Heating
Mirror heating on the driver's and front passenger's doors is controlled by the respective door modules.
The BCU receives the outside temperature value via the K-bus. This outside temperature value is converted to a
switch on-time percentage according to the following table and then transmitted via the P-bus to the two door
modules. Mirror heating is active with the ignition at position II.
If the wiper is switched on, the switch on-time percentage is raised in accordance with the following table.
If the park heat function (if fitted) is selected, mirror heating is automatically selected.
Temperature in °C< -10° -10 to 0° 0 to 15° 15 to 25° 25 to 35° > 35°
Switch on-time percentage 100% 75% 50% 25 % 0 % 0 %
Switch on-time percentage
with wiper
100% 100% 75% 50% 25% 0 %
DOORS
76-1-6 DESCRIPTION AND OPERATION
Mirror Fold
1 Mirror fold button
The mirror fold function, standard for Japan and available as optional equipment for other markets, enables the
mirrors to be electrically folded.
The “mirror fold” button is located in the switching centre of the driver's door for operation of the fold-in mechanism
for both outside mirrors. When the “mirror fold” button is pressed, both mirror drives are driven in the fold-in direction
by the relevant switching centre.
If the “mirror fold” button is pressed again, the two door mirrors are returned to their original positions.
Since it is possible, with frequent mirror fold-in operations, to cause the mirror motors to overheat, a repeat lockout
facility is provided.
If the “mirror fold” button is pressed more than 5 times within 1 minute, the mirrors will extend and the mirror fold-in
feature is disabled for 3 minutes.
M76 4548
1
DOORS
DESCRIPTION AND OPERATION 76-1-7
Tail Door
Tail Door Construction
DOORS
76-1-8 DESCRIPTION AND OPERATION
The steel tail door is of a two-piece horizontally split design.
The upper tail door, attached to the body with zinc coated hinges, is supported, when fully open, by two gas struts.
The tinted, heated rear window is bonded to the window aperture.
Bolted to the upper tail door, and accessed by removing the upper trim panel, are the fixed spoiler, a suppressor and
a centrally mounted single blade wash/wipe assembly. The fixed spoiler is fitted with a high level brake light and an
optional multi-band telephone antenna.
Fitted to the upper tail door lower sill, accessed by removing the lower trim panel, is the upper tail door latch and
locking mechanism, operated by a flush fitting switch located between the two number plate lights. To illuminate the
loading area two lights are fitted to the lower trim panel. A “P”-section rubber weather seal is fitted to the lower sill.
The lower tail door is mounted on two spring-damped hinges and supported, when lowered, by two straps. A carpeted
sprung-flap seals the gap between the tail door and the luggage area. Centrally mounted, is the striker plate for the
upper tail door .
The two lower tail door locks engage the laterally mounted striker plates fitted on the vertical tail door frames, and are
operated by a switch that can be accessed when the upper tail door is in the open position.
Tail Door Operation
The components for the tail door locking system are:
l Upper tail door external push-button
l Lower tail door internal push-button
l CDL button on centre console
l Upper tail door actuator
l Lower tail door actuators, fitted directly to locks
l Relay for upper tail door actuator
l Relay for lower tail door actuators.
Upper Tail Door Button
The upper tail door can be opened electrically by pressing the taildoor release button on the remote handset, the
external switch located between the number plate lamps or by pressing the tail door release button on the fascia.
Upper Tail Door
The centrally mounted upper tail door lock can be operated by either the tailgate mounted switch, the remote handset
or the tail gate release button mounted on the central console.
In an emergency, or when there is no electrical power, the upper tail door can be manually unlocked by pulling a cable
attached to a plastic toggle located in the upper tail door trim panel.
Lower Tail Door
The lower tail door is released by the operating switch fitted to the upper sill and is only accessible with the upper tail
door open.
DOORS
DESCRIPTION AND OPERATION 76-1-9
Lower Tail Door Switch Location
Actuators
The actuators are accommodated in their respective CDL units and powered by relays.
Relays
The relay for the upper tail door is integrated in the BCU.
The relay for the lower tail door is fitted at the RH rear of the load space.
Lower Tail Door Locks
Each of the two lateral locks is directly fitted to it's respective actuator. Fitted to the top of each lock is a manual release
lever.
DOORS
76-1-10 DESCRIPTION AND OPERATION
Operation
General
The operating logic for controlling the tailgate locking system is a function of the BCU.
NOTES:
l It is possible to open the tail door with the remote control irrespective of the vehicle central locking status
l At vehicle speeds > 5 mph (8 km/h) it is not possible to operate the tail door . This facility prevents inadvertent
operation while driving.
Upper Tail Door
The tail door is released by a special central locking unit with return spring shuttle.
To unlock/release the tail door, the CDL unit is powered directly for 0.7 seconds via a load switching relay in the BCU.
The table below shows the functions of the upper tail door for which the central locking unit is activated.
Power is applied to the actuator in the CDL unit and the tail door opens.
The return spring in the CDL unit re-establishes the initial position of the CDL unit.
Lower Tail Door
The lower tail door is opened by a special CDL unit with return spring (shuttle).
The CDL unit is activated by the BCU via a load switching relay and power is applied for 0.7 seconds.
The actuator releases the tail door lock so that the lower tail door can be opened. After power has been applied, the
return spring resets the CDL unit to its initial position.
The table below shows the functions of the lower tail door for which the CDL unit is activated.
Repeat Lockout
A repeat lockout facility similar to the repeat lockout function of the CDL is used in order to protect the motors from
thermal overload in the event of the tail door being locked/unlocked too often in succession.
Inside upper tailgate
push-button
Outside upper tailgate
push-button
Remote control for upper
tailgate
Terminal R + v>0 −− −
Unlock + +
Lock + +
Central secure − +
Selective unlock + +
"+" = CDL unit is activated; "-" = CDL unit is not activated
Inside lower tailgate push-button
When upper tail door open When upper tail door closed
Terminal R + v>0 −−
Unlock + −
Lock + −
Central secure + −
Selective unlock + −
"+" = CDL unit is activated; "-" = CDL unit is not activated
INTERIOR TRIM COMPONENTS
DESCRIPTION AND OPERATION 76-3-1
INTERIOR TRIM COMPONENTSDESCRIPTION AND OPERATION
Interior Mirror
1 Rear light sensor
2 Alarm LED
3 Front light sensor
4 Universal transmitter channel buttons (NAS
only)
5 Universal transmitter LED (NAS only)
INTERIOR TRIM COMPONENTS
76-3-2 DESCRIPTION AND OPERATION
Description
General
The interior mirror incorporates either manual or automatic dimming and has the security system alarm LED installed
on the underside of the mirror housing. Manual dimming is performed by rotating the cover of the alarm LED.
Automatic dimming is performed by electrochromic mirror glass.
On vehicles with a central door locking system operated by an infrared remote handset, the infrared receiver is also
incorporated into the mirror housing.
NAS vehicles all have automatic dimming and also incorporate a HomeLink® universal transmitter in the mirror
housing.
NOTE: HomeLink is a registered trademark owned by the Prince Corporation, Holland, Michigan, USA. Tel: 1–800–
355–3515.
The interior mirror is connected to the vehicle wiring by an electrical connector concealed by the finishers covering
the mounting stem. A permanent power feed from the passenger compartment fusebox supplies the alarm LED and,
where fitted, the infrared receiver, which are controlled by the Body Control Unit (BCU). When the ignition switch is in
position II, a second power feed, also from the passenger compartment fusebox, supplies the electrochromic mirror
circuits and the universal transmitter.
Interior Mirror Harness Connector
Interior Mirror Harness Connector C0698 Pin Details
Pin No. Description Input/Output
1 Reverse gear selected Input
2 Infrared receiver data Input/Output
3 Ignition power supply Input
4 Driver door mirror electrochromic element Output
5 Driver door mirror electrochromic element Output
6 Front passenger door mirror electrochromic element Output
7 Front passenger door mirror electrochromic element Output
8 Battery power supply Input
9 Alarm LED Input
10 Ground –
INTERIOR TRIM COMPONENTS
DESCRIPTION AND OPERATION 76-3-3
Electrochromic Mirror
The electrochromic mirror automatically dims to reduce glare from the headlights of following vehicles in dark or low
light conditions. In addition to dimming the interior mirror, the electrochromic mirror circuits also control the dimming
of the two door mirrors, via positive and negative connections between the interior mirror and each door mirror.
A light sensor on the front of the mirror monitors ambient light at the front of the vehicle and a light sensor in the mirror
glass monitors the light coming from behind the vehicle. When the light from behind the vehicle exceeds the ambient
light level, the electrochromic circuits simultaneously dim the interior and door mirrors. Dimming is inhibited when
reverse gear is selected. The interior mirror is provided with a reverse gear signal by the Light Check Module (LCM).
Universal Transmitter
The universal transmitter can operate up to three home or office remotely operated systems (e.g. garage door/gate
openers, lighting and security systems), replacing the individual hand held transmitters required for each system. The
universal transmitter can learn the radio frequency codes of most current transmitters.
WARNING: The universal transmitter must not be used with any garage door that lacks safety ‘stop’ and
‘reverse’ features, as required by federal safety standards (this includes any garage or door opener model
manufactured before April 1 1982). A garage door opener which cannot ‘detect’ an object in the path of a
closing door and then automatically ‘stop’ and ‘reverse’ the door, does not meet current federal safety
standards. Using a garage door opener without these features increases the risk of serious injury or death.
The universal transmitter incorporates three buttons, one for each channel, and an amber LED installed on the
underside of the interior mirror. When one of the buttons is pressed the universal transmitter outputs the radio signal
programmed for the related channel (if any) and illuminates the LED to confirm transmission.
Hand held transmitters are programmed into the universal transmitter as follows:
1 Turn the ignition switch to position II.
2 Press and hold the two outer buttons of the universal transmitter until the LED begins to flash, then release the
buttons. This initialises the universal transmitter and erases previous settings from all three channels.
WARNING: When programming the universal transmitter in the vicinity of the affected system, the system
will operate. If the system controls garage doors or gates, ensure they are clear of people and objects
to prevent personal injury or damage to equipment.
3 Place the signal emitting end of the hand held transmitter against the underside of the interior mirror.
4 Simultaneously press and hold the activation button on the hand held transmitter and the chosen button of the
universal transmitter. When the LED of the universal transmitter flashes rapidly, indicating the channel has been
programmed, release the buttons.
NOTE: The LED flashes slowly at first and can take up to a minute before it flashes rapidly.
5 To programme another channel on the universal transmitter, repeat steps 3 and 4.
6 Turn the ignition switch to 0.
The radio signals used to operate some home/office systems incorporate a code protection feature. After a channel
has been programmed from the hand held transmitter, these systems will need to be trained to accept the signal from
the universal transmitter. To check if a system is code protected, press the appropriate universal transmitter button.
If the LED flashes rapidly for 1 to 2 seconds, before illuminating permanently, the system has a code protection
feature.
The system is trained to the universal transmitter, as follows:
1 Locate the training button on the system receiver. Refer to the system's literature for details.
2 Press the training button on the system receiver for 1 to 2 seconds.
3 On the vehicle, press and hold the appropriate universal transmitter button. When the amber LED stops flashing
rapidly (1 to 2 seconds), indicating training is complete, release the button.
INTERIOR TRIM COMPONENTS
76-3-4 DESCRIPTION AND OPERATION
SEATS
DESCRIPTION AND OPERATION 76-5-1
SEATSDESCRI PTION AND OPERATION
Front Seat
SEATS
76-5-2 DESCRIPTION AND OPERATION
Description
Front Seats
There are three versions of seat available for the New Range Rover. The front seats are fitted with the seat belt bolted
to the seat rail. The seat buckle, bolted to the seat frame, is supplied, for the US market, with a seat belt warning
switch.
The three seat options available are:
l Manual seat – finished in cloth
l Electric seat – finished in cloth
l Contour seat – finished in Oxford Leather.
The electric and contour seats are fitted with a folding armrest (manually adjustable) on the inboard side of the seat,
additional optional equipment is: seat heating and memory recall facility.
Manual Seats
Manual Seat — Adjustment
1 Seat back adjustment
2 Height adjustment
3 Lumbar support adjustment
4 Forward/backward adjustment
5 Cushion front edge adjustment (driver's seat
only)
The manual seats are adjustable in the following axes:
l Forward/backward
l Seat height
l Seat angle — driver's seat only
l Backrest angle
l Headrest height and angle.
Electrically adjusted lumbar support, in the horizontal and vertical axes is available as optional equipment.
SEATS
DESCRIPTION AND OPERATION 76-5-3
Electric Seats
The electric seats are adjusted in the following axes by switches fitted in the seat side trim panel:
l Forward/back adjustment
l Seat cushion height
l Seat cushion angle – driver's seat only
l Backrest angle
l Lumbar support – horizontal and vertical.
The seat has the following manual adjustments:
l Headrest angle
l Headrest height.
Contour Seats
Contour Seat – Adjustment
1 Memory store and preset switches
2 Upper backrest adjustment
3 Seat backrest adjustment
4 Forward/backward/cushion height/cushion
angle adjustment
5 Lumbar support adjustment
In addition to the electric seat adjustments the Contour seat has the following additional functions:
l Electrical adjustment of the seatback head adjustment
l Seat angle adjustment – driver and passenger seats
l Seat heating.
Memory Function
This function, available as optional equipment, has three memory positions stored for the seats and exterior mirrors.
The switch for this function is located on driver's seat outer side trim panel.
Controlled by the Body Control Unit, the memory recall functions are:
l Forward/backward adjustment
l Seat height
l Seat angle – driver's side only
l Backrest angle
l External mirror adjustment – left and right
l Steering column forward/backward adjustment.
SEATS
76-5-4 DESCRIPTION AND OPERATION
Rear seats
The three rear bench style seats, designed to fold forward to increase the rear load space, are asymmetrically split
60:40 and are equipped with seat belts and adjustable head rests. The outer seats have optional heating.
Seat Control Unit
The are two versions available; the standard and contour version.
The control unit is configured to move the seat, depending on the version fitted, through 6 axes. It can also be
configured for adjusting the steering column.
Standard Control Unit
The standard seat control unit is capable of controlling four seat motors with hall sensors and two steering column
motors. The switches for the controls are located in the control unit and shaped to give an indication of their
corresponding function.
The control functions are:
1 Forward/backward movement
2 Seat height
3 Recline
4 Tilt.
The steering column switches are connected to the unit via a 4 pin connector. The functions are:
1 Up/down
2 Forward/backward
Contour Version
The contour version is fitted with two additional motors to control the seat in the following axes:
1 Seatback head adjustment
2 Seat angle.
Seat Control Unit Sub-Systems
The are two versions available; the standard and contour version.
The system consists of an electrical sub-system and a mechanical sub-system and is controlled by the seat control
unit fitted to the seat valance.
The electrical sub-system comprises the following components:
SEATS
DESCRIPTION AND OPERATION 76-5-5
1 Seat switch panel
2 Body Control Unit (BCU)
3 Seat relay
4 Lumbar pump
5 Lumbar deflate solenoid valve
6 Seat squab motor
7 Seat cushion up/down motor
8 Seat forward/backward motor
9 Seat cushion front up/down motor
SEATS
76-5-6 DESCRIPTION AND OPERATION
The mechanical sub-system comprises the following components:
l Gear wheels
l Rack and pinion assemblies.
Seat Power Relay
Located in the passenger compartment fusebox, the seat power relay supplies battery voltage for seat adjustment.
The motors are energised when a selection is made.
Seat Switch Pack
Each seat switch pack, mounted on the seat valance, provides movement in the following axes:
l Seat forward/backward adjust
l Seat height adjustment
l Seat angle adjustment
l Backrest angle adjustment
l Backrest head adjustment
l Head restraint height adjustment.
Manual adjustment of the seat position can be carried out at any time, having priority over memory recall. The control
unit sequences the order of adjustment.
Seat Forward/Backward Motor
The seat forward/backward motor is a permanent magnet motor coupled to a rack and pinion assembly. Should the
motor seize or stick for 6 seconds or more, an internal thermal cut-out switch will trip to remove voltage from the motor.
Reset time for the switch is 35 seconds. Two pins within the seat switch pack control the seat forward/backward motor.
Both pins are normally earthed. Operating the backward switch applies voltage to that pin while the other pin remains
earthed. Operating the forward switch reverses power and earth to the motor allowing the motor to run in the opposite
direction.
Seat Cushion Front Up/Down Motor
The seat cushion front up/down motor is a permanent magnet motor coupled to a rack and pinion assembly. Should
the motor seize or stick for 6 seconds or more an internal thermal cut out switch will trip to remove voltage from the
motor. Reset time for the switch is 35 seconds. Two pins within the seat switch pack control the seat cushion front up/
down motor. Both pins are normally earthed. Operating the up switch applies voltage to that pin while the other pin
remains earthed. Operating the down switch reverses power and earth to the motor allowing the motor to run in the
opposite direction.
Seat Cushion Rear Up/ Down Motor
The seat cushion rear up/down motor is a permanent magnet motor coupled to a rack and pinion assembly. Should
the motor seize or stick for 6 seconds or more, an internal thermal cut out switch will trip to remove voltage from the
motor. Reset time for the switch is 35 seconds. Two pins within the seat switch pack control the seat cushion rear up/
down motor. Both pins are normally earthed. Operating the up switch applies voltage to that pin while the other pin
remains earthed. Operating the down switch reverses power and earth to the motor allowing the motor to run in the
opposite direction.
Seat Squab Forward/Backward Motor
The squab forward/backward motor is a permanent magnet motor coupled to a rotary rack and pinion assembly.
Should the motor seize or stick for 6 seconds or more, an internal thermal cut out switch will trip to remove voltage
from the motor. Reset time for the switch is 35 seconds. Two pins within the seat switch pack control the squab fore/
aft motor. Both pins are normally earthed. Operating the fore switch applies voltage to that pin while the other pin
remains earthed. Operating the aft switch reverses power and earth to the motor allowing the motor to run in the
opposite direction
Lumbar Pump
The lumbar pump inflates a bladder in the squab which provides extra support for the seat occupant. With no load on
the seat it takes approximately 10 seconds to completely inflate the bladder. With a load of 25 kg (55 lb) it takes
approximately 15 seconds to inflate the bladder. A pressure cut off switch in the system will operate at 0.12 to 1.93
bar (1.8 to 28 lbf.in
2
). The lumbar bladder can be replaced independently of the pump. The components are not
serviceable.
SEATS
DESCRIPTION AND OPERATION 76-5-7
Manual Adjustment of Drive Motors
The seats can be manually adjusted at any time. Positioning is interrupted if manual adjustment is required during
automatic adjustment (memory recall). The manual adjustment is not effective before the switch is operated again.
Due to the sequential activation of the drive motors, the switch requests are prioritised in the following order:
l Forward/backward adjustment
l Backrest
l Height
l Angle
l Head restraint
l Backrest head
l Steering column angle
l Steering column forward/backward adjustment.
SEATS
76-5-8 DESCRIPTION AND OPERATION
Seat Heating
Description
The heated seat system is fitted to both the driver's and front passenger's seat and selected by individual push-button
switches, each with an integrated LED display.
Location of Seat Heating Controls
The electrical sub-system consists of the following components:
l Seat heater switches
l Seat heater elements (squab/backrest)
l Temperature control unit
l Temperature sensor.
Temperature Control Unit
Feedback of the seat temperature is via a Negative Temperature Coefficient (NTC) sensor within the seat cushion.
The resistance of this sensor changes with the temperature of the seat cushion allowing the temperature control unit
to raise or lower the voltage to the seat heater elements to raise or lower their temperature.
An ignition feed is supplied via the heater switch. The temperature sensor supplies an input. Output is a supply to the
cushion heater element and an earth.
Seat Heater Switches
The two push-button switches, fitted in the central console, each have an integrated functional display and, to assist
system fault diagnosis, a self-test function. The display indicates the heating level selected and, when used for fault
diagnosis, the fault code.
Both LEDs OFF – No heating
Two LEDs ON – High level heating (44°C)
One LED ON – Low level heating (39°C)
The seat heater switches supply an ignition feed to the temperature control unit. When a seat heater switch is
operated, current flows to the seat heater elements causing them to heat the seat.
The switch regulates the level of seat heating if its internal temperature starts to rise above 85°C. Initially the level of
seat heating is reduced to 88 % then progressively reduced until, if the internal temperature exceeds 95°C, the system
shuts-down.
M76 4553
SEATS
DESCRIPTION AND OPERATION 76-5-9
Seat Heater Elements
The seat heater elements are located in the seat cushion and squab. The cushion and squab heater elements are
wired in parallel. Total power consumption at 13.5 volts is approximately 115 Watts. The cushion heater element has
an input feed from the temperature control unit or heater switch and an output to the squab heater element, which
outputs to earth.
Operation
When the seat heater switch is initially pressed High level heating is selected, pressing the switch a second time
selects Low level heating and pressing the switch a third time switches the heating off.
The seat heaters are thermostatically controlled and will operate intermittently to maintain a predetermined
temperature. The indicator lights in the switches will remain illuminated until either the heaters are manually turned
off, or the starter switch is turned off.
CAUTION: The seat heaters consume considerable power from the battery. For this reason, they should
ONLY be operated while the engine is running.
When the seat heater switch is operated, power is supplied to the heater elements in the seat, causing the seat to
heat up. The temperature control unit senses seat temperature via the sensor in the cushion and regulates voltage to
the seat heater elements to maintain a constant temperature.
The heater elements increase and then maintain the seat at a temperature of between 37 and 44°C.
Fault Finding
In the self-test mode the switch indicates faults by displaying a flashing code.
The sequence to select test mode is :
1 Press the heating switch with the ignition off
2 With the switch depressed turn on the ignition switch to Position II
3 Release the switch, this activates the self-test mode
4 After 10 seconds the flashing code is displayed.
The flashing code indicates the following faults
l 1 Flash — Switch overtemperature (T > 95°C)
l 2 Flashes — Short circuit and/or interruption in the sensor
l 3 Flashes — Short circuit and/or interruption in the heating elements.
With the switch set to test mode, maximum heating is selected and both lamps are lit. If a fault is identified the heating
is switched off and, after 10 seconds, the left LED switches off , this LED generates the flashing code. If no fault is
detected the LED remains unlit.
To return to the test mode the switch is pressed twice and the sequence starts again. To cancel the test mode the
ignition switch is turned off.
SEATS
76-5-10 DESCRIPTION AND OPERATION
SUNROOF
DESCRIPTION AND OPERATION 76-6-1
SUNROOFDESC RIPTION AND OPERATION
Sunroof Layout
1 Closing panel
2 Clamp plate
3 Glass panel
4 Sunshade panel
5 Carriage
6 Sunroof motor
7 Frame
SUNROOF
76-6-2 DESCRIPTION AND OPERATION
Sunroof
General
The sunroof is electrically operated by a three-way switch co-located with the forward interior light assembly. The
sunroof drive unit, operating the sunroof panel to the tilt or open positions, is actuated by the integrated sunroof control
electronics.
The sunroof frame is bolted to mounting points on the roof panel. The frame, constructed from pressed steel, supports
all the sunroof components.
A rubber gaiter is fitted between the sides of the glass panel and drive assembly. The gaiter, reducing wind noise with
the sunroof in the tilt position, conceals the drive linkage.
The sunroof drive unit, accessible by removing the motor access panel ( integral with the forward interior light
assembly), is mounted ahead of the roof segment between the roof liner and lower frame section of the sunroof. It
comprises a motor with add-on reduction gear (worm drive), two hall-effect integral position sensors and integrated
control circuit. The software within the integrated control unit is configured to meet individual national regulations. It
is connected by a 13–pin multiplug to the P-Bus.
The worm drive drives a gear in a cast housing attached to the end of the motor. The gear has a small pinion gear
attached to the outer part of its spindle. The pinion engages with the spiral cables to form a rack and pinion drive.
Rotation of the motor turns the pinion which in turn drives the cables in the required direction.
The two cables are attached either side of the pinion. One end of each cable is attached to the guide. The opposite
end is clamped in its position on the pinion by a riveted bracket. The cables run in metal tubes to the guides. As the
sunroof panel is closed, the cables are pulled through the metal tubes. The displaced cable is guided into plastic tubes
which protect the cable and prevent it snagging. The cables are made from rigid spring steel and therefore can push
as well as pull the sunroof along the guides.
A sunshade is also located in the guides. When the sunroof panel is opened or tilted, the sunshade moves rearward.
When the sunroof panel is opened, two brackets on the sunshade engage with the panel as it is retracted. The
sunshade is then pulled back by the retracting panel. When the panel is closed, the sunshade remains retracted until
pulled manually to its closed position.
Drain hoses are connected to the front and rear corners of the frame. The drain hoses are located inside the 'A' and
'D' post pillars to allow water which has collected in the frame to escape. A one-way valve is fitted to the end of each
drain hose to prevent the ingress of dirt and moisture.
Servicing
Servicing is limited to adjusting the glass panel and replacing the drive unit. The drive unit is accessed by removing
the access panel fitted to the forward interior light panel.
SUNROOF
DESCRIPTION AND OPERATION 76-6-3
Operation
General
Sunroof Controls
1 Access panel for motor drive output shaft 2 Sunroof switch
The sunroof is operated by the three-way switch, via the Body Control Unit (BCU), with the following switch position
options:
l Rest position
l Open sliding/tilting sunroof (sliding open)
l Open by pressing and holding (one-touch function for sliding open)
l Raise sliding/tilting sunroof (tilting open)
l Close sliding/tilting sunroof (sliding shut/tilting shut)
l Close by over-pressing (one-touch function for sliding closed).
The drive is automatically shut down when the limit positions are reached. Limit position shutdown is initiated by the
integral increment sensor isolating the motor. Limit position shutdown occurs even if the control remains actuated or
is operated a further time in the direction of the limit position.
If a failure of the sunroof motor occurs, the sunroof can be closed manually. Access to the motor drive output shaft,
in the roof access panel, enables the fitting of a special key which can be used to manually drive the sunroof to the
closed position.
The sliding/tilting sunroof is operational with the ignition switch in position II for one-touch operation and position I for
operating the control. In addition to the basic functional specifications, nationally specific specifications are configured
via the encoding of the basic module. The necessary signals are transmitted via the P-Bus. If no signals are
transmitted via the P-Bus, the functions remain limited to manual operation.
NOTE: The encoding functions are configured using TestBook/T4
The following functions are available:
Manual Operation
The desired sunroof position can be selected by operating the control in the open/tilt/close sliding/tilting sunroof
positions. The control must be pressed permanently to do this.
M76 4507
2
1
SUNROOF
76-6-4 DESCRIPTION AND OPERATION
One-touch Function
Pressing and holding the sunroof switch momentarily, for either the open or close selection, will enable the sliding/
tilting sunroof to travel fully to the selected closed position. This selection can be interrupted by operating the switch
a further time.
If the "tilting" control is operated while the panel position is within the "sliding open" range, the roof automatically
moves to the limit position of tilting. This process can be interrupted by operating the control a further time.
The one-touch functions are encodable. This is a function of TestBook/T4.
Anti-Trap Function
The anti-trap function, configured to meet the specific requirements of individual national regulations, operates by
monitoring the torque output of the sliding/tilting sunroof drive. It operates when the sunroof is closing and the opening
is greater than 4 mm. To ensure that the sunroof fully closes it is disabled for the last 4 mm of travel.
NOTE: The encoding functions are configured using TestBook/T4
Operating during one-touch operation, actuation in the first switch position and during one-touch closing, the anti-trap
function is disabled when emergency closing (panic mode) is selected.
After the anti-trap function has been activated the sunroof will return, depending on vehicle configuration, at maximum
system speed, to the point at which the close selection was initially made.
Convenience Operation
The sunroof and windows can be fully closed or opened by holding the door key in either the locking or unlocking
position, or with the remote control. Releasing the key before the operation is completed will stop the sunroof
travelling.
The anti-trap function also operates when convenient closing is selected.
If the key is returned to the rest position, any convenience function that is currently in progress is terminated. If the
control is operated during a convenience function, the convenience function that is currently in progress is terminated
and must be restarted. Automatic resumption after the control is released is not permissible.
Consumer Shutdown
During the starting process (Ignition position II), the sunroof is deactivated via the P-bus. The current selection , e.g.
opening or one-touch functions, is immediately terminated and sunroof movement is halted.
If an undervoltage of less than 9.5 V occurs, the one-touch operation that is in progress will be terminated and no new
sliding/tilting sunroof movement is initiated.
Sleep Mode
To reduce the current consumption of the vehicle, the sunroof control system switches to an electricity-saving mode
after receiving the telegram "Go to Sleep" from the BCU via the P-Bus. In this condition manual operation of the
sunroof will result in the loss of its absolute position. It will require re-initialising.
The electricity-saving mode is exited again by any telegram on the P-bus. The first telegram on the P-bus need not
be evaluated. However, the P-Bus must not be influenced by the wake-up process. The following telegrams in the
sliding/tilting sunroof must not be misinterpreted or destroyed by the wake-up process.
Fault Patterns
The following fault patterns are provided:
l Overriding temporary shutdown (max. switch-on time 15 s)
l Shutdown of the drive in event of relay contacts sticking or faulty semiconductor after max. 500 ms
l Shutdown of the drive in event of no signal from the increment sensors after max. 300 ms
l Substitute function (e.g. motor stop) in event of implausible signals from sliding/tilting sunroof control and other
faults (signal lines)
l Repeat interlock (by software, as substitute for motor thermo switch).
SUNROOF
DESCRIPTION AND OPERATION 76-6-5
Diagnosis
The sunroof control unit has a built in test function to allow self-checking and self-diagnosis.
The exchange of information with the diagnostic unit takes place through the basic module via the P-bus. It can be
used to identify three possible faults.
1 Mechanical stiffness (fault in the sunroof unit)
1 Implausible input signals (control fault)
2 Electronic fault.
Initialisation
Initialising the sunroof allows the control unit to learn the end positions of the motor's travel. The hall sensors provide
pulses for motor rotation, the control module counts the pulses and determines where the panel is by memorizing the
stored pulses.
If the system is not initialised, the sunroof will only operate in the tilt up and slide close positions.
Initialisation Procedure
Pressing and holding the sunroof switch in either the tilt up or slide close positions for 15 seconds momentarily
operates the sunroof motor.
The control module memorizes the pulses from the hall sensors on the next activation of the motor by driving the panel
to its end run positions. The control module senses an amperage increase and determines the end run position. The
counted number of pulses is then used as the basis for calculating the panel position.
SUNROOF
76-6-6 DESCRIPTION AND OPERATION
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-1
AIR CONDITIONINGDESCRIPTION AND OPERAT ION
Refrigerant System Component
Location
1 High pressure servicing connection
2 Low pressure servicing connection
3 Thermostatic expansion valve
4 Evaporator
5 Receiver drier module
6 Condenser
7 Compressor
AIR CONDITIONING
82-2 DESCRIPTION AND OPERATION
Heater Assembly and Ducting
Component Location
6
8
44
3
4
8
6
7
2
3
M82 0781
1
9
2
55
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-3
1 Forced ventilation outlet
2 Windscreen duct
3 Face level duct
4 Front footwell duct
5 Heater assembly
6 Rear footwell duct
7 Rear face duct
8 Rear blower (high line system only)
9 Rear face duct extension (low line system only)
AIR CONDITIONING
82-4 DESCRIPTION AND OPERATION
Control System Component Location
1 Heater temperature sensor (LH on low line, LH
& RH on high line)
2 In-car temperature sensor
3 ATC ECU (high line version)
4 Single coolant valve (low line only)
5 Dual coolant valve (high line only)
6 Auxiliary coolant pump
7 Pollution sensor (high line only)
8 Refrigerant pressure sensor
9 Sunlight sensor (high line only)
10 Evaporator temperature sensor
11 Steering wheel recirculation switch
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-5
FBH System Component Location
1 FBH fuel pipe tank connection
2 FBH receiver (where fitted)
3 Changeover valve (where fitted)
4 FBH fuel pump
5 FBH unit
AIR CONDITIONING
82-6 DESCRIPTION AND OPERATION
Description
General
Either a low or high line Air Conditioning (A/C) system is installed on the vehicle. The low line system features
automatic control of a common temperature setting for both sides of the passenger compartment, with manual control
of the blower speed, air recirculation and air distribution. The high line system is fully automatic with separate
temperature settings for the LH and RH sides of the passenger compartment and manual overrides for blower speed,
air recirculation and air distribution. The high line system also incorporates independent temperature and volume
control for the rear passengers. The low and high line systems both include:
l A refrigerant system
l An air inlet housing
l A heater assembly
l Distribution ducts
l Two forced ventilation outlets
l An Automatic Temperature Control (ATC) ECU and sensors
l An auxiliary coolant pump
l A coolant valve.
The high line system incorporates the following additional components:
l A second coolant valve
l A pollution sensor
l A rear blower unit.
A Fuel Burning Heater (FBH) system is installed as standard on Td6 models and as an option on V8 models. The FBH
is a supplementary heater installed in the heater coolant circuit. The FBH can be operated without the engine running
to pre-heat the passenger compartment and after the engine starts to reduce the heater coolant warm-up time. On
Td6 models, the FBH also boosts the heater coolant temperature while the engine is running at low ambient air and
engine coolant temperatures, to maintain heater performance at an acceptable level.
Refrigerant System
The refrigerant system transfers heat from the vehicle interior to the outside atmosphere to provide the heater
assembly with dehumidified cool air. The system comprises:
l A compressor
l A condenser and receiver drier
l A thermostatic expansion valve
l An evaporator
l Refrigerant lines.
The system is a sealed, closed loop, filled with a charge weight of R134a refrigerant as the heat transfer medium. Oil
is added to the refrigerant to lubricate the internal components of the compressor.
To accomplish the transfer of heat, the refrigerant is circulated around the system, where it passes through two
pressure/temperature regimes. In each of the pressure/temperature regimes, the refrigerant changes state, during
which process maximum heat absorption or release occurs. The low pressure/temperature regime is from the
thermostatic expansion valve, through the evaporator to the compressor; the refrigerant decreases in pressure and
temperature at the thermostatic expansion valve, then changes state from liquid to vapour in the evaporator, to absorb
heat. The high pressure/temperature regime is from the compressor, through the condenser and receiver drier to the
thermostatic expansion valve; the refrigerant increases in pressure and temperature as it passes through the
compressor, then releases heat and changes state from vapour to liquid in the condenser.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-7
Refrigerant System Schematic
1 Evaporator
2 Thermostatic expansion valve
3 Desiccant (in modulator)
4 Filter (in modulator)
5 Electric cooling fan
6 Refrigerant pressure sensor
7 Condenser
8 Compressor
9 High pressure servicing connection
10 Low pressure servicing
11 Blower
12 Air flows:
a Ambient air flow through condenser
b Fresh/Recirculated air flow through blower
c Cooled air flow to vehicle interior
7
4
3
M82 0815
8
6
5
10
12b
12b
11
12b
1
12c
2
A
B
9
12a
12b
AIR CONDITIONING
82-8 DESCRIPTION AND OPERATION
Compressor
The compressor circulates the refrigerant around the system by compressing low pressure, low temperature vapour
from the evaporator and discharging the resultant high pressure, high temperature vapour to the condenser.
The compressor is a fixed displacement unit attached to a mounting bracket on the engine. A dedicated drive belt on
the engine crankshaft drives the compressor via a pulley and an electrically actuated clutch. Operation of the clutch
is controlled by the ATC ECU.
Compressor Assembly
1 Clutch connector
2 Pulley
3 Outlet port
4 Inlet port
Condenser
The condenser transfers heat from the refrigerant to the surrounding air to convert the vapour from the compressor
into a liquid. A receiver drier module, integrated onto the LH side of the condenser, incorporates a filter and a
desiccant to remove solid impurities and moisture from the refrigerant. The receiver drier module also functions as a
reservoir for liquid refrigerant, to accommodate changes of heat load at the evaporator.
The condenser is installed immediately in front of the radiator.
The condenser is classified as a sub-cooling condenser and consists of a fin and tube heat exchanger installed
between two end tanks. Divisions in the end tanks separate the heat exchanger into a three pass upper (condenser)
section and a single pass lower (sub-cooler) section, which are interconnected by the receiver drier module. The
desiccant pack and the filter in the receiver drier module are serviceable items retained in position by a threaded plug.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-9
Condenser Assembly
1 Cap
2 Spring clip
3 Sealing plug
4 Desiccant module
5 Condenser
6 Outlet pipe
7 Inlet pipe
AIR CONDITIONING
82-10 DESCRIPTION AND OPERATION
Thermostatic Expansion Valve
The thermostatic expansion valve meters the flow of refrigerant into the evaporator, to match the refrigerant flow with
the heat load of the air passing through the evaporator matrix.
The temperature and pressure of the refrigerant leaving the evaporator act on the thermostatic expansion valve to
control the volume of refrigerant flowing through the evaporator. The warmer the air flowing through the evaporator
matrix, the more heat available to evaporate refrigerant and thus the greater the volume of refrigerant allowed through
the metering valve.
Evaporator
The evaporator is installed in the heater assembly between the blower and the heater matrix, to absorb heat from the
exterior or recirculated air. Low pressure, low temperature refrigerant changes from liquid to vapour in the evaporator,
absorbing large quantities of heat as it changes state.
Most of the moisture in the air passing through the evaporator condenses into water, which drains through the floorpan
to the underside of the vehicle through two drain tubes.
Evaporator and Thermostatic Expansion Valve
1 Insulated connecting pipes
2 Thermostatic expansion valve
3 Evaporator
Refrigerant Lines
To maintain similar flow velocities around the system, the diameter of the refrigerant lines varies to suit the two
pressure/temperature regimes. The larger diameters are installed in the low pressure/temperature regime and the
smaller diameters are installed in the high pressure/temperature regime.
Low and high pressure charging connections are incorporated into the refrigerant lines near the front RH corner of the
engine compartment.
Air Inlet Housing
The air inlet housing directs fresh air into the heater unit. The air inlet housing is centrally mounted on the engine
bulkhead, below a ventilation grille in the bonnet, and secured to the bulkhead closing panels.
A serviceable particle filter, or particle/odour filter, is installed in the air inlet housing to prevent odours and/or
particulate matter from entering the vehicle with the fresh air.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-11
Air inlet Housing
1 Air outlet to heater assembly
2 Fixing lug
3 Filter flap catch
4 Filter flap
5 Particle/carbon filter
6 Inlet grille
7 Seal
AIR CONDITIONING
82-12 DESCRIPTION AND OPERATION
Heater Assembly
The heater assembly controls the temperature, volume and distribution of air supplied to the distribution ducts as
directed by selections made on the ATC ECU control panel. The assembly is installed on the vehicle centre-line,
between the fascia and the engine bulkhead. The heater assembly consists of a casing formed from a series of plastic
mouldings. Internal passages integrated into the casing guide the air through the casing and separate it into two flows,
one for the LH outlets and one for the RH outlets. Two drain outlets at the bottom of the casing are connected to
overboard drain hoses in the sides of the transmission tunnel.
The heater assembly incorporates:
l A blower
l A heater matrix
l Control flaps
l Control flap motors
l The thermostatic expansion valve and the evaporator of the refrigerant system
l The evaporator temperature sensor and either one (low line system) or two (high line system) heater matrix
temperature sensors.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-13
Low Line Heater Assembly
1 Fresh air inlet
2 Fresh/Recirculated air flap
3 Face level temperature blend flap control
4 Insulated refrigerant pipes
5 Windscreen air outlet
6 Face level air outlets
7 Front footwell air outlet
8 Rear face level air outlet
9 Rear footwell air outlet
10 Water drain
11 Coolant pipes
12 Fresh/Recirculated air flaps motor
13 Distribution flaps motor
AIR CONDITIONING
82-14 DESCRIPTION AND OPERATION
High Line Heater Assembly
1 Fresh air inlet
2 Fresh/Recirculated air flap
3 Ram air flap
4 Face level temperature blend flap control
5 Rear face level temperature blend motor
6 Insulated refrigerant pipes
7 Ram air flaps motor
8 Windscreen air outlet
9 Face level air outlets
10 Front footwell air outlet
11 Footwell (RH) and face level (LH) air flaps
motors
12 Rear face level air outlet
13 Rear footwell air outlet
14 Water drain
15 Windscreen distribution motor
16 Coolant pipes
17 Fresh/Recirculated air flap motor
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-15
Blower
The blower is installed between the air inlets and the evaporator, and consists of two open hub, centrifugal fans
powered by a single electric motor. Operation of the electric motor is controlled by the ATC ECU via an output stage
(voltage amplifier) installed in the outlet of the RH fan.
To produce the seven blower speeds the ATC ECU outputs a stepped control voltage between 0 and 8 V to the output
stage, which regulates a battery power feed from the passenger compartment fusebox to the blower. The control
voltage changes, in 1 V steps, between 2 V (blower speed 1) and 8 V (blower speed 7). If the control voltage is less
than 2 V the blower is off.
Blower Output Stage
AIR CONDITIONING
82-16 DESCRIPTION AND OPERATION
Heater matrix
The same heater matrix is used in both the low and high line heater assemblies. The heater matrix is internally divided
into two separate halves, with separate coolant inlets for each half and a common coolant outlet. On the low line
system, the two coolant inlets are connected to a common feed from the single coolant valve. On the high line system,
each coolant inlet pipe is connected to a feed from a separate coolant valve.
Heater Matrix Assembly
1 Low line connecting pipes 2 High line connecting pipes
Control Flaps
Control flaps in the heater assembly control the source of inlet air and the distribution and temperature of outlet air.
On both the low and high line heater assemblies, a fresh/recirculated air flap is installed in the air inlet on each side
of the heater assembly. A stepper motor drives the LH fresh/recirculated air flap and a Bowden cable transmits the
drive from the LH to the RH fresh/recirculated air flap. On the high line system, a ram air flap is installed inside each
fresh/recirculated air flap. A stepper motor drives the RH ram air flap and a Bowden cable transmits the drive from the
RH to the LH ram air flap.
Each side of the heater assembly contains separate distribution flaps for the footwell, face level and windscreen. The
related flaps on each side of the heater assembly are installed on common drive spindles. On the low line heater
assembly, the distribution flaps are driven by Bowden cables connected to a cam mechanism, which, in turn, is driven
by a stepper motor. On the high line heater assembly, each set of distribution flaps is driven by a separate stepper
motor.
On both the low and high line heater assemblies, a blend flap is installed below the face level outlets. The blend flap
is driven by a Bowden cable connected to a thumbwheel on the centre face vents in the fascia, and allows the
temperature of face level air to be modified with cold air direct from the evaporator.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-17
Fascia Face Level Vent
1 RH air control thumbwheel
2 Temperature control thumbwheel
3 LH air control thumbwheel
On high line heater assemblies, a blend flap is installed for the rear passenger face level outlet to allow the
temperature of rear face level air to be adjusted independently from the temperatures selected on the control panel.
The blend flap is driven by a stepper motor controlled by a thumbwheel on the rear passenger face vent. The blend
flap is also used to close off the rear face level outlet when maximum air output is required for the front outlets, e.g.
when defrost is selected.
Rear Passenger Face Level Vent
1 Blower control 2 Temperature control
AIR CONDITIONING
82-18 DESCRIPTION AND OPERATION
Control Flap Motors
Two types of electrical stepper motor are used to operate the control flaps in the heater assembly. A conventional 500
Hz stepper motor operates the recirculation flaps, on the low and high line systems. On the high line system, five bus
controlled 200 Hz stepper motors operate the ram air, distribution (windscreen, face level and footwell) and the rear
face level temperature control flaps. On the low line system a bus controlled stepper motor operates the distribution
flaps cam mechanism. All of the stepper motors are controlled by the ATC ECU. None of the stepper motors are
interchangeable.
Typical Control Flap Motor
1 Electrical connector
2 Release clip
3 Output shaft
Each bus controlled stepper motor incorporates a microprocessor and is connected to an M bus from the ATC ECU,
which consists of three wires making up power, ground and signal circuits. The microprocessor in each bus controlled
stepper motor is programmed with a different address. Each M bus message from the ATC ECU contains the address
of an individual bus controlled stepper motor, so only that motor responds to the message.
None of the stepper motors incorporate a feedback potentiometer. Instead, the ATC ECU determines the positions of
the flaps by using either their closed or open position as a datum and memorising the steps that it drives the individual
stepper motors. Each time the ignition is switched on, the ATC ECU checks the memorised position of the stepper
motors against fixed values for the current system configuration. If there is an error (e.g. after a power supply failure
during operation or after replacement of the ATC ECU), the ATC ECU calibrates the applicable stepper motors, to re-
establish the datums, by driving them fully closed or open before re-setting them to their nominal position. A calibration
run can also be invoked using TestBook/T4.
When any of the control flaps are set to fully closed or open, the ATC ECU signals the related stepper motor to move
the appropriate number of steps in the applicable direction. To accommodate build tolerances and wear, and to
ensure the flaps are held in the selected position, every 20 seconds the ATC ECU signals the stepper motor to move
an additional 10 steps in the relevant direction.
Distribution Ducts
Air from the heater assembly is distributed around the vehicle interior through distribution ducts to outlets in the fascia,
the front and rear footwells, and the rear of the cubby box between the front seats.
In the fascia, the distribution ducts are connected to fixed vents for the windscreen and side windows and adjustable
vent assemblies for face level air. An adjustable vent assembly is also installed on the rear of the cubby box for rear
face level air. The footwell outlets are fixed vents formed in the end of the related distribution ducts.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-19
Air Distribution
Forced Ventilation Outlets
The forced ventilation outlets promote the free flow of air through the passenger compartment. The outlets are
installed in the LH and RH rear quarter body panels and vent passenger compartment air into the sheltered area
between the rear quarter body panels and the rear bumper.
Rear Blower (High Line System Only)
The blower is installed between the front seats, in the rear face air duct, and consists of an open hub, centrifugal fan
powered by an electric motor. Operation of the electric motor is controlled by a thumbwheel on the rear passenger
face vent via the ATC ECU and an output stage (voltage amplifier) installed in the outlet of the fan.
The thumbwheel operates a variable potentiometer which outputs between 1.25 V (blower off) and 5 V (maximum
blower speed) to the ATC ECU. The ATC ECU then outputs a proportional control voltage between 0 and 5 V to the
output stage, which regulates a battery power feed from the rear blower relay to the blower to produce the related
blower speed.
The rear blower relay is installed in the rear fusebox and energised while the ignition is on.
AIR CONDITIONING
82-20 DESCRIPTION AND OPERATION
Rear Blower Output Stage
ATC ECU
The ATC ECU is installed in the centre of the fascia. An integral control panel contains push switches and rotary
switches/knobs for system control inputs. Orange tell-tale LED's in the switches and switch surrounds illuminate to
indicate the current settings of the system. The rotary temperature switch is graduated in degrees Celsius, except on
USA vehicles, where it is graduated in degrees Fahrenheit.
An in-car temperature sensor and associated electric fan are installed behind a grille in the control panel.
The ATC ECU processes inputs from the control panel switches and system sensors, then outputs the appropriate
signals to control the A/C system. In addition to controlling the A/C system, the ATC ECU also controls the following:
l The windscreen heater and windscreen wiper parking area heater (optional fit, not available on vehicles with infra
red protection glass)
l The windscreen washer jet heaters
l The rear window heater
l The front seat heaters.
Low Line Control Panel
1 Windscreen heater switch
2 LH front seat heater switch
3 Temperature switch
4 Blower switch
5 RH front seat heater switch
6 Distribution control knob
7 A/C switch
8 Recirculation switch
9 In-car temperature sensor
10 Rear window heater switch
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-21
The switches on the low line control panel have the following functions:
l Windscreen Heater Switch:Enabled only with the engine running. Pressing the switch energises the windscreen
heater and the windscreen wiper parking area heater for a set time period, until the switch is pressed again or
until the engine stops, whichever occurs first. A LED above the switch is illuminated while the heaters are on.
l LH and RH Seat Heater Switches:Activates the heater elements in the seat cushion and seat back at one of two
heat levels. The first press of the switch energises the heater elements at the higher heat setting and illuminates
two LED in the switch. A second press of the switch sets the heater elements to the lower heat setting and
extinguishes one of the LED's. A further press of the switch de-energises the heater elements and extinguishes
the second LED. The seat heaters remain on until selected off or the ignition is switched off.
l Temperature Switch: Adjusts the passenger compartment nominal temperature setting between 16 and 28 °C
(60 and 84 °F). The temperature range is engraved on the switch surround (°F for NAS, °C for rest of world). A
pointer on the switch indicates the selected temperature. In the minimum and maximum temperature positions,
the temperature is set to maximum cooling or maximum heating respectively.
l Blower Switch: For manual adjustment of blower speed. Up to seven LED's in the switch surround illuminate to
indicate the selected blower speed.
l Distribution Control Knob: For manual adjustment of air distribution. Includes AUTO setting where distribution
flaps are set to a nominal comfort position.
l A/C Switch: Activates the A/C compressor. Allows the A/C compressor to be selected off for economy operation.
A LED above the switch is illuminated when the A/C compressor is selected on.
l Recirculation Switch: For manual selection of fresh or recirculated air. A LED above the switch is illuminated
when recirculated air is selected.
l Rear Window Heater Switch: Enabled only with the engine running. Pressing the switch energises the rear
window heater for a set time period, until the switch is pressed again or until the engine stops, whichever occurs
first. A LED above the switch is illuminated while the heater is on.
AIR CONDITIONING
82-22 DESCRIPTION AND OPERATION
High Line Control Panel
1 Windscreen heater switch
2 LH front seat heater switch
3 LH temperature switch
4 Automatic mode switch
5 Blower switch
6 RH front seat heater switch
7 RH temperature switch
8 A/C switch
9 Recirculation switch
10 Maximum A/C switch
11 Windscreen distribution switch
12 Face distribution switch
13 Footwell distribution switch
14 In-car temperature sensor
15 Defrost programme switch
16 Rear window heater switch
The switches on the high line control panel have the following functions:
l Windscreen Heater Switch:Energises the windscreen heater and the windscreen wiper parking area heater for a
set time period, until the switch is pressed again or until the engine stops, whichever occurs first. A LED above
the switch is illuminated while the heaters are on.
l LH and RH Seat Heater Switches:Activates the heater elements in the seat cushion and seat back at one of two
heat levels. The first press of the switch energises the heater elements at the higher heat setting and illuminates
two LED in the switch. A second press of the switch sets the heater elements to the lower heat setting and
extinguishes one of the LED's. A further press of the switch de-energises the heater elements and extinguishes
the second LED. The seat heaters remain on until selected off or the ignition is switched off.
l LH and RH Temperature Switches:Adjusts the nominal temperature settings of the LH and RH sides of the
passenger compartment between 16 and 28 °C (60 and 84 °F). The temperature range is engraved on the switch
surrounds. A pointer on each switch indicates the selected temperature. In the minimum and maximum
temperature positions, the system operates at maximum cooling or maximum heating respectively.
l Automatic Mode Switch: Activates the automatic modes for air volume and distribution and also activates the
compressor. Separate LED's in the automatic mode switch illuminate when the blower and the distribution control
flaps are in automatic mode. Manually selecting the blower speed or a distribution switch extinguishes the related
LED.
l Blower Switch: For manual adjustment of blower speed. Up to seven LED's in the switch surround illuminate to
indicate the selected blower speed.
l A/C Switch: Controls activation of the A/C compressor. Allows the A/C compressor to be selected off for economy
operation. A LED above the switch is illuminated when the A/C compressor is selected on.
l Recirculation Switch: For manual or automatic selection of fresh or recirculated air. Two LED's above the switch
illuminate to indicate the mode and position of the recirculation flaps. The first press of the switch sets the
recirculation flaps to automatic mode and illuminates the LH LED. A second press of the switch manually sets
the recirculation flaps to the recirculation position, extinguishes the LH LED and illuminates the RH LED. A further
press of the switch manually sets the recirculation flaps to the fresh air position and extinguishes the RH LED.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-23
l Maximum A/C Switch: For selection of maximum A/C when the ignition is on or rest heating when the ignition is
off. A LED above the switch is illuminated when maximum cooling or rest heating is selected.
l Distribution Switches (Windscreen, Face and Footwell): For manual selection of air distribution in any
combination of windscreen, face and footwell outlets. A LED above each switch illuminates when a selection is
made.
l Defrost Programme Switch: Activates a programme that automatically selects the windscreen heater on,
activates the compressor and changes the system settings to direct dry heat to the windscreen. A LED above
the switch is illuminated while the defrost programme is active.
l Rear Window Heater Switch: Enabled only with the engine running. Pressing the switch energises the rear
window heater for a set time period, until the switch is pressed again or until the engine stops, whichever occurs
first. A LED above the switch is illuminated while the heater is on.
Inputs and Outputs
Five electrical connectors provide the interface between the ATC ECU and the vehicle/heater assembly wiring.
Both the low and high line systems receive ambient temperature, engine coolant temperature, engine speed and
vehicle speed inputs in K bus messages from the instrument pack. If the K bus messages are missing or faulty, the
ATC ECU adopts the following default values:
l Ambient temperature = 0 °C (32 °F)
l Engine coolant temperature = 80 °C (176 °F)
l Engine speed = 800 rev/min
l Vehicle speed = zero.
If a fault develops in the input from the temperature selector switch on the control panel, the ATC ECU adopts a default
value of 24 °C (75 °F).
ATC ECU Harness Connector C0249 Pin Details
ATC ECU Harness Connector C0923 Pin Details
Pin No. Description System Input/Output
Low High
1 Front seat heating battery power supply Yes Yes Input
2 LH front seat heater Yes Yes Output
3 RH front seat heater Yes Yes Output
Pin No. Description System Input/Output
Low High
1 Rear blower switch signal No Yes Input
2 Rear blower switch power supply No Yes Output
3 Automatic distribution switch Yes No Input
4 LH heater matrix temperature sensor No Yes Input
5 RH heater matrix temperature sensor Yes Yes Input
6 Evaporator temperature sensor Yes Yes Input
7 Blower control voltage Yes Yes Output
8 Rear temperature switch No Yes Input
9 Sensor ground (evaporator, and heater
temperature sensors)
Yes Yes –
10 to 12 Not used –– –
13 Recirculation flap motor signal 2 Yes Yes Input
14 Recirculation flap motor signal 2 Yes Yes Output
15 Recirculation flap motor signal 1 Yes Yes Output
16 Recirculation flap motor signal 1 Yes Yes Input
17 Rear blower and temperature switch power
supply
No Yes Output
18 Not used –– –
AIR CONDITIONING
82-24 DESCRIPTION AND OPERATION
ATC ECU Harness Connector C1629 Pin Details
ATC ECU Harness Connector C1630 Pin Details
ATC ECU Harness Connector C2295 Pin Details
Pin No. Description System Input/Output
Low High
1 Ignition power supply Yes Yes Input
2 Sunlight sensor ground No Yes –
3 K bus Yes Yes Input/Output
4 Delayed accessory power Yes Yes Input
5 LH coolant valve Yes Yes Output
6 RH coolant valve No Yes Output
7 HRW relay Yes Yes Output
8 Windscreen washer jet heater relay Yes Yes Output
9 Auxiliary coolant pump Yes Yes Output
10 Refrigerant pressure sensor signal Yes Yes Input
11 Not used –– –
12 Pollution sensor signal No Yes Input
13 Pollution sensor power supply No Yes Output
14 Windscreen heater relay Yes Yes Output
15 LH seat heating temperature sensor Yes Yes Output
16 RH seat heating temperature sensor Yes Yes Output
17 Engine full load signal Yes Yes Input
18 LH sunlight sensor signal No Yes Input
19 RH sunlight sensor signal No Yes Input
20 Refrigerant pressure sensor ground Yes Yes –
21 Refrigerant pressure sensor power supply Yes Yes Output
22 Coolant changeover valve Yes Yes Output
23 Instrument illumination Yes Yes Input
24 Sunlight sensor power supply No Yes Output
25 Pollution sensor heater ground No Yes –
26 Pollution sensor heater power supply No Yes Output
Pin No. Description System Input/Output
Low High
1 Battery power supply Yes Yes Input
2 A/C compressor clutch Yes Yes Output
3 System ground Yes Yes –
Pin No. Description System Input/Output
Low High
1 M bus power supply No Yes Output
2 M bus ground No Yes –
3 M bus interface line No Yes Input/Output
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-25
Sensors
Both the low and the high line systems incorporate:
l An in-car temperature sensor
l A refrigerant pressure sensor
l An evaporator temperature sensor
l A heater matrix temperature sensor.
The high line system also incorporates:
l A second heater matrix temperature sensor
l A sunlight sensor
l A pollution sensor.
In-car Temperature Sensor
The in-car temperature sensor is an encapsulated Negative Temperature Coefficient (NTC) thermistor that provides
the ATC ECU with an input of passenger compartment air temperature. The in-car temperature sensor is installed
behind a grille in the ATC ECU control panel. An electric fan in the ATC ECU runs continuously, while the ignition is
on, to draw air through the grille and across the in-car temperature sensor.
The ATC ECU uses the signal from the in-car temperature sensor for control of the coolant temperature valve(s),
blower speed and air distribution.
The signal voltage from the in-car temperature sensor is between 0 and 5 V. The ATC ECU monitors the signal voltage
and defaults to a temperature of 20 °C (68 °F) if it goes out of the range 0.573 – 4.882 V:
l If the signal voltage is less than 0.573 V, the ATC ECU assumes there is a short circuit to ground
l If the signal voltage is more than 4.882 V, the ATC ECU assumes there is an open circuit or a short circuit to
battery.
Refrigerant Pressure Sensor
The refrigerant pressure sensor provides the ATC ECU with a pressure input from the high pressure side of the
refrigerant system. The refrigerant pressure sensor is located in the refrigerant line between the condenser and the
thermostatic expansion valve.
The ATC ECU supplies a 5 V reference voltage to the refrigerant pressure sensor and receives a return signal voltage,
between 0 and 5 V, related to system pressure.
The ATC ECU uses the signal from the refrigerant pressure sensor to protect the system from extremes of pressure
and to calculate compressor load on the engine for idle speed control. The ATC ECU also transfers the pressure value
to the Engine Control Module (ECM), via the K bus, instrument pack and CAN bus, for use in controlling the speed of
the engine cooling fan.
To protect the system from extremes of pressure, the ATC ECU disengages the compressor clutch if the pressure:
l Decreases to 1.9 ± 0.2 bar ( 27.5 ± 3 lbf/in
2
): the ATC ECU engages the compressor clutch again when pressure
increases to 2.8 ± 0.2 bar (40.5 ± 3 lbf/in
2
)
l Increases to 33 ± 1 bar (479 ± 14.5 lbf/in
2
): the ATC ECU engages the compressor clutch again when pressure
decreases to 23.5 ± 1 bar (341 ± 14.5 lbf/in
2
).
Evaporator Temperature Sensor
The evaporator temperature sensor is a NTC thermistor that provides the ATC ECU with a temperature signal from
the air outlet side of the evaporator. The evaporator temperature sensor is installed in the RH side of the heater
assembly casing, and extends into the core of the evaporator.
The ATC ECU uses the input from the evaporator temperature sensor to control the engagement and disengagement
of the compressor clutch, to prevent the formation of ice on the evaporator.
The signal voltage from the evaporator temperature sensor is between 0 and 5 V. The ATC ECU monitors the signal
voltage and defaults to a temperature of 0 °C (32 °F) if it goes out of the range 0.157 – 4.784 V:
l If the signal voltage is less than 0.157 V, the ATC ECU assumes there is a short circuit to ground
l If the signal voltage is more than 4.784 V, the ATC ECU assumes there is an open circuit or a short circuit to
battery.
AIR CONDITIONING
82-26 DESCRIPTION AND OPERATION
Heater Matrix Temperature Sensor
The heater matrix temperature sensor is a NTC thermistor that provides the ATC ECU with a temperature signal from
the air outlet side of the heater matrix. On low line systems, a single sensor is installed in the rear of the heater
assembly casing, to the right of the centre-line. On high line systems, two sensors are installed, one each side of the
centre-line.
The ATC ECU uses the input from the heater matrix temperature sensor(s) to control the operation of the coolant
valve(s).
The signal voltage from each heater matrix temperature sensor is between 0 and 5 V. The ATC ECU monitors the
signal voltage and defaults to a temperature of 55 °C (131 °F) if it goes out of the range 0.173 – 4.890 V:
l If the signal voltage is less than 0.173 V, the ATC ECU assumes there is a short circuit to ground
l If the signal voltage is more than 4.890 V, the ATC ECU assumes there is an open circuit or a short circuit to
battery.
Sunlight Sensor
The sunlight sensor consists of two photoelectric cells that provide the ATC ECU with inputs of light intensity, one as
sensed coming from the left of the vehicle and one as sensed coming from the right. The inputs are a measure of the
solar heating effect on vehicle occupants and used by the ATC ECU to adjust blower speed, temperature and
distribution to improve comfort. The sensor is installed in the centre of the fascia upper surface.
If one of the photoelectric cells is faulty, the output from the other photoelectric cell is used for both sides of the vehicle.
If both photoelectric cells are faulty, the ATC ECU uses a default value of zero.
Pollution Sensor
The pollution sensor allows the ATC ECU to monitor the ambient air for the level of hydrocarbons and oxidized gases
such as nitrous oxides, sulphur oxides and carbon monoxide. The pollution sensor is installed at the rear of the
radiator, on the upper RH side of the viscous fan housing.
The ATC ECU outputs a battery power supply to heat the pollution sensor to operating temperature, and a 5 V
reference voltage for the signal. The signal voltage from the pollution sensor is between 0 and 5 V.
If there is a fault with the pollution sensor, the ATC ECU disables automatic closing of the recirculation flaps on
detection of pollutants.
Auxiliary Coolant Pump
The auxiliary coolant pump is an electric pump that ensures there is a satisfactory flow rate through the heater matrix
at low engine speeds. The auxiliary coolant pump is installed in the engine compartment, in a rubber mounting
attached to the side of the LH suspension turret. Operation of the auxiliary coolant pump is controlled by a power
supply from the ATC ECU.
Coolant Valve
The coolant valve controls the coolant flow to the heater matrix. A single coolant valve controls the coolant flow to
both sides of the heater matrix on low line systems. On high line systems, separate coolant valves control the coolant
flow to each side of the heater matrix. The coolant valves are installed in the engine compartment on a bracket
attached to the side of the LH suspension turret.
Each coolant valve is a normally open solenoid valve controlled by a Pulse Width Modulated (PWM) signal from the
ATC ECU. The ATC ECU changes the length of time the coolant valve is open each duty cycle between 0 second
(valve closed) and 3.6 seconds (valve held open). On the high line system, the PWM signals to the two valves are
phase offset by 1.8 seconds to reduce coolant flow fluctuations.
FBH System
The system consists of a FBH unit, a FBH fuel pump and a changeover valve. On vehicles with the remote operation
feature, the system also includes a FBH receiver and a remote handset.
Fuel for the FBH system is taken from the vehicle fuel tank, through a line attached to the fuel tank's fuel pump unit,
and supplied via the FBH fuel pump to the FBH unit. In the FBH unit, the fuel delivered by the FBH fuel pump is burned
and the resultant heat output is used to heat the engine coolant. The changeover valve isolates the heater coolant
circuit from the engine coolant circuit
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-27
An ECU integrated into the FBH unit controls the operation of the FBH unit and the FBH fuel pump. The ATC ECU
controls the changeover valve. System operation is initiated by:
l The instrument pack, via the ATC ECU, using I and K bus messages, for parked heating selections made on the
Multi Information Display (MID) or Multi-Function Display (MFD)
l The remote handset, via the TV antenna, TV amplifier and the FBH receiver, using radio and hardwired signals,
for instant activation of parked heating
l The ATC ECU, using K bus messages, for additional heating while the engine is running.
FBH Fuel Pump
The FBH fuel pump regulates the fuel supply to the FBH unit. The FBH fuel pump is installed below the RH side of
the fuel tank in a rubber mounting attached to the rear subframe. The pump is a self priming, solenoid operated
plunger pump. The ECU in the FBH unit outputs a pulse width modulated signal to control the operation of the pump.
When the pump is de-energised, it provides a positive shut-off of the fuel supply to the FBH unit.
Sectioned View of FBH Fuel Pump
1 Solenoid coil
2 Plunger
3 Filter insert
4 Fuel line connector
5 'O' ring seal
6 Spring
7 Piston
8 Bush
9 Fuel line connector
10 Non return valve
The solenoid coil of the FBH fuel pump is installed around a housing which contains a plunger and piston. The piston
locates in a bush, and a spring is installed on the piston between the bush and the plunger. A filter insert and a fuel
line connector are installed in the inlet end of the housing. A non return valve and a fuel line connector are installed
in the fuel outlet end of the housing.
While the solenoid coil is de-energised, the spring holds the piston and plunger in the 'closed' position at the inlet end
of the housing. An 'O' ring seal on the plunger provides a fuel tight seal between the plunger and the filter insert,
preventing any flow through the pump. When the solenoid coil is energised, the piston and plunger move towards the
outlet end of the housing, until the plunger contacts the bush; fuel is then drawn in through the inlet connection and
filter. The initial movement of the piston also closes transverse drillings in the bush and isolates the pumping chamber
at the outlet end of the housing. Subsequent movement of the piston then forces fuel from the pumping chamber
through the non return valve and into the line to the FBH unit. When the solenoid de-energises, the spring moves the
piston and plunger back towards the closed position. As the piston and plunger move towards the closed position, fuel
flows past the plunger and through the annular gaps and transverse holes in the bush to replenish the pumping
chamber.
M80 0471
1 23 4
5678
109
AIR CONDITIONING
82-28 DESCRIPTION AND OPERATION
FBH Unit
The FBH unit is installed in the passenger side rear of the engine compartment, below the battery. It is connected in
series with the coolant supply to the heater assembly. Two electrical connectors on the FBH unit connect it to the
vehicle wiring.
FBH Unit Components
1 Coolant outlet hose
2 Electrical connectors
3 Air inlet filter
4 Mounting bracket
5 Exhaust pipe
6 Fuel supply line
7 Coolant inlet hose
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-29
Sectioned View of FBH Unit
1 Combustion air fan
2 Burner housing
3 ECU
4 Heat exchanger
5 Burner insert
6 Exhaust
7 Glow plug/flame sensor
8 Evaporator
9 Coolant inlet
10 Circulation pump
11 Fuel inlet
12 Coolant outlet
13 Air inlet
M80 0472
1 2
4
5
67
8
9
11
12
13
10
3
AIR CONDITIONING
82-30 DESCRIPTION AND OPERATION
The FBH unit consists of:
l A circulation pump
l A combustion air fan
l A burner housing
l An ECU/heat exchanger
l An air inlet hose
l An exhaust pipe
l An air inlet filter.
Circulation Pump: The circulation pump is installed at the coolant inlet to the FBH unit to assist the coolant flow
through the FBH unit and the heater assembly. The pump runs continuously while the FBH unit is in standby or active
operating modes. While the FBH unit is inactive, coolant flow is reliant on the engine coolant pump and the auxiliary
coolant pump.
Combustion Air Fan: The combustion air fan regulates the flow of air into the unit to support combustion of the fuel
supplied by the FBH pump and to purge and cool the FBH unit. A canister type filter is included in the air inlet supply
line to prevent particulates entering and contaminating the FBH unit.
Burner Housing: The burner housing contains the burner insert and also incorporates connections for the exhaust
pipe, the coolant inlet from the circulation pump and the coolant outlet to the heater assembly. The exhaust pipe
directs exhaust combustion gases to atmosphere through a pipe below the FBH unit.
The burner insert incorporates the fuel combustion chamber, an evaporator and a glow plug/flame sensor. Fuel from
the FBH fuel pump is supplied to the evaporator, where it evaporates and enters the combustion chamber to mix with
air from the combustion air fan. The glow plug/flame sensor provides the ignition source of the fuel:air mixture and,
once combustion is established, monitors the flame.
ECU/Heat Exchanger: The ECU controls and monitors operation of the FBH system. Ventilation of the ECU is
provided by an internal flow of air from the combustion air fan. The heat exchanger transfers heat generated by
combustion to the coolant. A sensor in the heat exchanger provides the ECU with an input of heat exchanger casing
temperature, which the ECU relates to coolant temperature and uses to control system operation. The temperature
settings in the ECU are calibrated to compensate for the difference between coolant temperature and the heat
exchanger casing temperature detected by the sensor. Typically, as the coolant temperature increases, the coolant
will be approximately 7 °C (12.6 °F) hotter than the temperature detected by the sensor; as the coolant temperature
decreases, the coolant will be approximately 2 °C (3.6 °F) cooler than the temperature detected by the sensor.
Changeover Valve
The changeover valve is a normally open solenoid valve installed between the supply and return sides of the heater
coolant circuit. The changeover valve is located in the engine compartment on the engine bulkhead. When de-
energised, the changeover valve connects the heater coolant circuit to the engine coolant circuit. When energised,
the changeover valve isolates the heater coolant circuit from the engine coolant circuit.
The changeover valve is controlled by a power feed from the ATC ECU.
FBH Receiver
The FBH receiver translates the FBH request radio signals, relayed from the antenna receiver, into a voltage output
to the FBH unit. When a request for parked heating is received, the FBH receiver outputs a battery power feed to the
FBH unit. When a request to switch off parked heating is received, the FBH receiver disconnects the power feed.
The FBH receiver has a permanent power feed from the vehicle battery and is connected to the antenna receiver by
a coaxial cable.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-31
FBH Remote Handset
1 Antenna
2 Off button
3 On button
4 LED
The remote handset allows parked heating to be remotely controlled up to a minimum of 100 m (328 ft) from the
vehicle. On and off buttons activate and de-activate parked heating, a red LED illuminates to indicate when parked
heating is active and when the on/off signals have been received by the vehicle. The remote handset is powered by
two serviceable 1.5 V batteries located under a cover on the rear of the handset.
FBH Remote Handset Battery Replacement
M82 0835
4
1
2
3
M82 0836
AIR CONDITIONING
82-32 DESCRIPTION AND OPERATION
DESCRIPTION AND OPERATION
A/C Control Diagram – Low Line System,
Sheet 1 of 2
A = Hardwired connection; B = K bus; L = M bus
M82 0822A
X
1
23
5
6
10
9
11
13
22
24
25
23
8
12
A
B
14
4
7
L
15
16
18
20
19
21
17
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-33
1 Ignition switch
2 Fuse 34, passenger compartment fusebox
3 Fuse 12, passenger compartment fusebox
4 HRW
5 Fuse 64, passenger compartment fusebox
6 Blower output stage
7 HRW relay
8 Blower
9 Coolant valve
10 Compressor clutch
11 Changeover valve
12 Auxiliary coolant pump
13 Fresh/Recirculated air flaps motor
14 Air distribution motor
15 LH washer jet
16 RH washer jet
17 Washer jet heater relay
18 Wiper park heater
19 Windscreen LH heater
20 Windscreen RH heater
21 Windscreen heater relay
22 Heater temperature sensor
23 ATC ECU
24 Evaporator temperature sensor
25 Refrigerant pressure sensor
AIR CONDITIONING
82-34 DESCRIPTION AND OPERATION
A/C Control Diagram – Low Line System,
Sheet 2 of 2
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus; D = CAN bus; F = RF transmission; K = I bus; M = P
bus
M82 0827B
16
6
7
8
10
9
12
13
11
15
14
X
A
B
A
K
F
B
D
C
1
2
4
5
3
M
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-35
1 BCU
2 Passenger door module
3 Passenger door mirror
4 Drivers door module
5 Drivers door mirror
6 FBH unit
7 FBH receiver
8 Remote handset
9 RH side window antenna
10 Antenna amplifier
11 Diagnostic socket
12 Multi function display
13 Multi information display
14 Steering wheel recirculation switch
15 Instrument pack
16 ECM
AIR CONDITIONING
82-36 DESCRIPTION AND OPERATION
A/C Control Diagram – High Line System,
Sheet 1 of 2
A = Hardwired connection; B = K bus; L = M bus
M82 0821A
X
Auto
PR
O
G
M
A
X
30
31
3
4
5
6
7
8
9
11
12
10
14
17
13
25
26
16
28
29
27
15
A
B
L
1
2
18
19
22
23
21
24
20
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-37
1 HRW
2 HRW relay
3 Fuse 12, passenger compartment fusebox
4 Rear passenger face vent
5 Fuse 64, passenger compartment fusebox
6 Blower
7 Blower output stage
8 Rear blower relay
9 Rear blower output stage
10 Dual coolant valve
11 Rear blower
12 Compressor clutch
13 Pollution sensor
14 Changeover valve
15 Auxiliary coolant pump
16 Sunlight sensor
17 Fresh/Recirculated air flaps motor
18 LH washer jet
19 RH washer jet
20 Washer jet heater relay
21 Wiper park heater
22 Windscreen LH heater
23 Windscreen RH heater
24 Windscreen heater relay
25 RH heater temperature sensor
26 LH heater temperature sensor
27 ATC ECU
28 Evaporator temperature sensor
29 Refrigerant pressure sensor
30 Ignition switch
31 Fuse 34, passenger compartment fusebox
AIR CONDITIONING
82-38 DESCRIPTION AND OPERATION
A/C Control Diagram – High Line System,
Sheet 2 of 2
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus; D = CAN bus; F = RF transmission; K = I bus; L = M
bus; M = P bus
M82 0826B
1
3
4
5
6
7
12
11
8
10
9
14
15
13
2
16
X
L
A
K
B
C D
17
19
18
21
20
M
F
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-39
1 ECM
2 Instrument pack
3 Windscreen distribution motor
4 Face level distribution motor
5 Footwell distribution motor
6 Rear face level temperature blend motor
7 Ram air motor
8 Remote handset
9 RH side window antenna
10 Antenna amplifier
11 FBH receiver
12 FBH unit
13 Diagnostic socket
14 Multi function display
15 Multi information display
16 Steering wheel recirculation switch
17 BCU
18 Drivers door module
19 Passenger door module
20 Passenger door mirror
21 Drivers door mirror
AIR CONDITIONING
82-40 DESCRIPTION AND OPERATION
Operation
General
Both the low and high line systems operate on the reheat principle. The air entering the heater assembly is cooled to
a constant value by the evaporator and then reheated as necessary by the heater matrix to produce the
temperature(s) selected on the control panel.
To determine the various system settings, the ATC ECU derives a reference value (called the Y factor) from:
l The temperature setting on the control panel
l The ambient temperature
l The in-car temperature.
The reference value is measured in %, where –27.5% means maximum cooling is required and 100% means
maximum heating is required. On the high line system, separate reference values are produced for the LH and RH
sides of the heater assembly.
On both the low and high line systems the reference value is used for temperature control. On the high line system
the driver's side reference value is also used for flap positioning and blower speed calculations.
When the ignition is turned off the ATC ECU memorises the system settings and resumes the same settings the next
time the ignition is switched on.
Compressor Control
The compressor is engaged by pressing either the automatic mode switch, defrost switch, A/C switch or maximum A/
C switch. To prevent a dip in engine speed when the engine is at idle, a time delay of approximately 0.5 second is
built into the compressor engagement process. The time delay allows the ECM to increase throttle angle and fuelling
in anticipation of the additional load on the engine when the compressor engages.
When it receives an input to engage the compressor, the ATC ECU sends a message to the ECM, via the K bus,
instrument pack and CAN bus, to advise that it wants to engage the compressor. Provided there are no engine
management problems, the ECM responds by increasing throttle angle and fuelling and sending a message granting
the request to the ATC ECU over the CAN bus, instrument pack and K bus. When it receives the grant message, the
ATC ECU energises the compressor clutch provided the following conditions exist:
l Engine speed is more than 400 rev/min
l Evaporator temperature is more than 3 °C (37 °F)
l The refrigerant pressure is within limits
l Battery voltage is less than 16 V
l The blower is running
l There are no faults detected by the ATC ECU.
The compressor remains engaged until selected off or the required conditions no longer exist. If the evaporator
temperature decreases to approximately 2 °C (36 °F) the compressor is disengaged, then re-engaged when the
evaporator temperature increases to more than 3 °C (37 °F) again. If battery voltage exceeds 16 V for more than 5
seconds the compressor is disengaged, then re-engaged when voltage decreases to less than 15.8 V.
The compressor can also be disengaged by the ECM changing the grant message to a negative value or outputting
a hardwired signal direct to the ATC ECU. Changing the grant message involves a time delay of up to 4 seconds
before the ATC ECU de-energises the compressor clutch. The time delay allows the ECM to decrease throttle angle
and fuelling, in anticipation of the reduction in engine load when the compressor disengages, to prevent a sudden
increase in engine speed if the engine is at idle. The hardwired signal is used to obtain instant disengagement of the
compressor to ensure maximum acceleration when accelerator pedal demand suddenly goes from no load to full load.
When this occurs the ECM sends a 12 V signal on a hardwired connection direct to the ATC ECU. When it receives
the signal the ATC ECU immediately de-energises the compressor clutch.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-41
Engine Idle Speed Control
The ATC ECU signals the ECM to increase engine idle speed settings if a high current application is switched on or
if low battery voltage is detected. The signal consists of a message transmitted via the K bus, instrument pack and
CAN bus, and increases idle speed between 100 and 200 rev/min. The ATC ECU requests the engine idle speed
increase when the following high current applications are switched on:
l Rear window heater
l Blower, at speed 6 or 7
l Headlamp main beam.
The engine idle speed increase is also requested if battery voltage decreases to less than 11.4 V. The speed increase
request is discontinued when battery voltage increases to more than 12.2 V again.
Engine Cooling Fan Control
The engine's electric cooling fan is controlled by the ECM. When the compressor is engaged the ATC ECU sends a
fan speed message between 0 (off) and 15 (maximum speed) to the ECM, via the K bus, instrument pack and CAN
bus. The ATC ECU requests the cooling fan on when:
l The vehicle speed is less than 44 mph (70 km/h)
l There is no fault with the compressor clutch circuit
l Battery voltage is less than 16 V.
The fan speed requested depends on the pressure in the refrigerant system. The higher the pressure the faster the
fan speed that is requested. When vehicle speed increases to more than 50 mph (80 km/h) the ATC ECU changes
the fan speed request to 0 until vehicle speed decreases to less than 44 mph (70 km/h) again.
If battery voltage increases to more than 16 V for 5 seconds the ATC ECU changes the fan speed to 0 until the voltage
decreases to less than 15.8 V.
Temperature Control
To determine the amount of heat required, in the form of coolant flow through the heater, the ATC ECU compares the
reference value with the heater matrix temperature and incorporates a correction factor to compensate for changes
of coolant flow rate with engine speed. From the resultant value the ATC ECU determines the open duration of the
coolant valve and outputs the appropriate control signal. On the high line system, separate values and output signals
are generated for each coolant valve to produce the individual temperature control for the LH and RH sides of the
passenger compartment.
When the temperature setting on the control panel is set to maximum, the ATC ECU signals the coolant valve to
remain open. When the temperature setting on the control panel is set to minimum, the ATC ECU signals the coolant
valve to remain closed.
On the high line system, the minimum setting is over-ridden when the defrost programme, maximum A/C, rest heating
or FBH functions are selected.
AIR CONDITIONING
82-42 DESCRIPTION AND OPERATION
Heater Coolant Circuit - Without FBH
1 Coolant valve (low line system)
2 Heater matrix
3 Coolant valves (high line system)
4 Auxiliary coolant pump
5 Engine cooling system
6 ATC ECU
Flap Control – Low Line System
While the ignition is on, the position of the recirculation flaps is manually controlled by selection of the recirculation
switch on the control panel and the steering wheel switch. If the recirculation flaps are in the recirculation position
when the ignition is switched off, the ATC ECU automatically sets them to the fresh air position, to ensure that fresh
air is available if a fault occurs with the recirculation flap drive circuit at the next ignition on.
The positions of the distribution flaps are manually controlled by selection of the distribution rotary switch on the
control panel. The flaps are also automatically positioned by the ATC ECU to open the:
l Windscreen and footwell outlets, when parked heating is initiated by the FBH
l Face and footwell outlets, when parked ventilation is initiated
l Windscreen outlets, when the ignition is switched off and the ambient temperature is less than 0 °C, or
windscreen and footwell outlets when the ignition is switched off and the ambient temperature is 0 °C and above.
M82 0819
5
2
4
3
2
1
6
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-43
Flap Control – High Line System
The position of the ram air flaps is automatically controlled by the ATC ECU. The positions of the recirculation flaps
and the distribution flaps are either automatically controlled by the ATC ECU or manually controlled by the related
switches.
Ram Air Flaps
The ATC ECU progressively closes the ram air flaps, in four steps, as vehicle speed increases, and opens them again
as vehicle speed decreases. At the maximum closed position, 90% of the fresh air inlet area is closed off. A hysteresis
of 9 mph (15 km/h) prevents the ram air flaps from hunting at a constant vehicle speed.
Ram Air Flap Positions
A = Flap position, % open; B = Opening speeds, mph (km/h); C = Closing speeds, mph (km/h)
M82 0816
0
20
40
60
80
100
28
(45)
47
(75)
63
(100)
91
(145)
38
(60)
100
(160)
56
(90)
72
(115)
A
B
C
AIR CONDITIONING
82-44 DESCRIPTION AND OPERATION
Recirculation Flaps
Unless the recirculation flaps are manually selected closed, using the recirculation switch on the control panel or the
steering wheel switch, they are normally open, but automatically closed by the ATC ECU under certain conditions.
Rapid Cooling: For rapid cooling of the passenger compartment, when the A/C system is selected on, if the driver's
side reference value is less than –20% and the ambient temperature is more than 6 °C (43 °F), the ATC ECU closes
the recirculation flaps. The ATC ECU opens the recirculation flaps after 12 minutes (temperate climates) or 20 minutes
(hot climates), if the driver's side reference value increases to more than –5% or if the ambient temperature decreases
to 6 °C (43 °F).
Pollution: When the ATC ECU detects a high level of pollutants, it sets the recirculation flaps to the recirculation
position for:
l 3 minutes if the A/C system is in the heating mode
l 10 minutes if the A/C system is in the cooling mode.
After the recirculation time period, the ATC ECU returns the recirculation flaps to the fresh air position. After 1 minute,
if the pollutants are still present, the ATC ECU repeats the recirculation cycle.
Ignition Off: If the recirculation flaps are in the recirculation position when the ignition is switched off, the ATC ECU
automatically sets them to the fresh air position, to ensure that fresh air is available if a fault occurs with the
recirculation flap drive circuit at the next ignition on. When the ignition is switched on, the ATC ECU sets the
recirculation flaps to the position they were in at ignition off.
Distribution Flaps
When a manual distribution selection is made on the control panel, the ATC ECU moves the distribution flaps to preset
positions. When the system is in the automatic mode, the ATC ECU uses maps of the driver's side reference value
to determine the position of the distribution flaps. Each distribution flap has a separate map, and there are separate
maps for temperate and hot climates. The mapped positions of the face level distribution flaps are given a correction
factor from the sunlight sensor inputs. The mapped positions of the distribution flaps are overridden by special
programmes, as follows:
Condensation Prevention: To prevent condensation on the windscreen, the ATC ECU closes the windscreen flaps for
12 seconds each time the engine starts. If a manual distribution selection is made during the 12 seconds, the
windscreen flaps revert to normal control.
The ATC ECU also closes the windscreen flaps when the reference value is less than 90% with the recirculation flaps
closed and the compressor is disengaged.
Cold Start: When the engine starts, if the system is in the automatic mode, the driver's side reference value is 100%
and the heater matrix temperatures is less than 30 °C (86 °F), the ATC ECU closes the face level and footwell flaps
and opens the windscreen flaps.
Duct Purging: After a cold start, if the system is in the automatic mode and the reference value is 100%, the ATC ECU
keeps the face level flaps closed until one of the heater matrix temperatures exceeds 60 °C (140 °F). The ATC ECU
then fully opens the face level flaps for 25 seconds to purge the ducts of cold air. After the purge the face level flaps
revert to normal automatic control. If, before or during the purge process, the reference value decreases below 100%,
the ignition has been on for 15 minutes, or a manual distribution selection is made, then the purge process is
cancelled.
Blower Control
In the automatic mode, blower speed is determined from reference temperature maps. In general terms, the more
heating or cooling required to achieve the temperature selected on the control panel with the driver's side temperature
switch, the faster the blower speed.
When maximum cooling is first required in the automatic mode, the ATC ECU runs the blower at full speed for a fixed
period regardless of any drop in passenger compartment temperature. Different time periods are incorporated for the
following markets:
l NAS and Gulf States
l Europe and ROW
l Japan.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-45
NAS and Gulf States have the longest time period with the blower at full speed and Japan the shortest. TestBook/T4
can be used to change the market setting so, in some cases, if a customer complains of the duration the blower runs
at full speed, changing the market setting could resolve the complaint.
When heating is required, blower speed is reduced if the engine is cold and then progressively increased to the
nominal setting as the engine coolant temperature increases from 20 to 50 °C (68 to 122 °F).
On the high line system, blower speed is also influenced by the sunlight sensor. At high light levels blower speed will
increase to increase the cooling effect.
When the blower is selected off temperature regulation is no longer possible so the ATC ECU disengages the
compressor, de-energises the auxiliary water pump and closes the coolant valves. Pressing any of the A/C system
switches restores blower operation and activates the required function. If the blower is selected off when the ignition
is switched off, the blower remains off if the ignition is switched on again within 15 minutes. If more than 15 minutes
elapses between the ignition being switched off and back on again, the ATC ECU switches the blower on at speed 1.
If battery voltage is low the ATC ECU reduces blower speed to conserve power. If battery voltage decreases to less
than 12 V, the ATC ECU decreases the blower signal voltage, and thus the voltage to the blower motor, in direct
proportion to the reduction in battery voltage.
Defrost Programme (High Line System Only)
When the defrost programme is selected the ATC ECU:
l Opens the windscreen distribution flaps and closes the face and footwell flaps
l Sets the recirculation flaps to the fresh air position
l Runs the blower at speed 7
l Activates the A/C compressor
l Activates the rear window heater
l Activates the windscreen heater (where fitted).
When the ambient temperature is 10 °C (50 °F) and below, the ATC ECU signals the coolant valves to remain open.
When the ambient temperature is more than 10 °C (50 °F), the ATC ECU checks the existing heater matrix
temperature and, if necessary, increases the open time of the coolant valves to produce a minimum heater matrix
temperature of 30 °C (86 °F).
The defrost programme is cancelled by pressing the defrost switch again, or pressing the automatic, A/C or maximum
A/C switches
Maximum A/C (High Line System Only)
Pressing the maximum A/C switch while the engine is running and the ambient temperature is more than 7 °C (45 °F)
provides the maximum cooling possible from the system to cool the passenger compartment down as rapidly as
possible. When maximum A/C is selected the coolant valves are held closed, the A/C compressor is engaged, the
blower speed is set to maximum and the recirculation flaps are set to the recirculation position. After 12 minutes the
recirculation flaps will be set to fresh air for 1 minute then returned to the recirculation position.
The maximum A/C function is cancelled when any of the other A/C system switches are pressed.
Rest Heating (High Line System Only)
When the engine is not running, pressing the maximum A/C switch activates the rest heating function to heat the
passenger compartment with residual heat from the engine. The rest heating function activates provided the following
conditions exist:
l It is less than 15 minutes since the ignition was selected off
l Ambient temperature is less than 15 °C (59 °F)
l On the previous ignition cycle engine temperature exceeded 70 °C (158 °F)
l Battery voltage is 11.4 V minimum.
To provide the rest heating function, the ATC ECU activates the auxiliary coolant pump, coolant valves, control flap
and blower. The ATC ECU regulates the temperature (to the driver setting selected before the ignition was switched
off), opens the face level distribution flaps and runs the blower at speed 4.
The rest heating function is cancelled after 15 minutes or when:
l The maximum A/C switch is pressed again
l The ignition is selected on
l Battery voltage decreases to less than 11 V.
AIR CONDITIONING
82-46 DESCRIPTION AND OPERATION
Rear Passenger Face Level Air (High Line System Only)
The volume and temperature of the air from the rear passenger face vent are adjusted with the thumbwheels at the
sides of the vent assembly. Each thumbwheel operates a variable potentiometer connected to the ATC ECU. The
volume thumbwheel controls stepless changes of rear blower speed between off and full speed. The temperature
thumbwheel controls the position of the rear passenger face level blend flap in the heater assembly when the driver's
side reference temperature is more than 0%.
Volume Control: The volume potentiometer outputs between 0 and 5 V to the ATC ECU. The ATC ECU translates the
voltage from the potentiometer into a signal voltage for the output stage in the rear blower. Potentiometer voltages of
less than 1.25 V are interpreted as a blower off selection and translate into a signal voltages less than 0.1 V.
Potentiometer voltages between 1.25 and 5 V are translated into proportional signal voltages between 0.1 and 5 V.
The ATC ECU automatically switches off the rear blower when:
l The defrost programme is active
l The main blower is selected off
l The engine cranks
l The ignition is selected off (the rear blower remains off during rest heating, parked heating and parked
ventilation).
Temperature Control: The temperature potentiometer outputs between 0 and 5 V to the ATC ECU. The ATC ECU
translates the voltage from the potentiometer into a blend flap position between 0% (cold) and 100% (hot) and outputs
the appropriate control signal on the M bus to the blend flap motor. Potentiometer voltages of less than 1.5 V translate
to a blend flap position of 0%. Potentiometer voltages of more than 3.4 V translate to a blend flap position of 100%.
Potentiometer voltages between 1.5 and 3.4 V translate linearly to blend flap positions between 0 and 100%.
Windscreen Heater (Where Fitted)
When the engine is running and the windscreen heater is selected on, the ATC ECU illuminates the LED above the
switch and energises the heated front screen relay attached to the passenger end of the fascia cross tube. If not
already active, the ATC ECU also activates the A/C compressor and the blower, and sets air distribution to
windscreen. After 10 minutes (when ambient temperature is –15 °C (5 °F) or above) or 17 minutes (when ambient
temperature is less than –15 °C (5 °F)), the ATC ECU extinguishes the LED and de-energises the heated front screen
relay. After the heater times out or is switched off, the timer in the ATC ECU is reset to zero.
Rear Window Heater
When the engine is running and the rear window heater is selected on, the ATC ECU illuminates the LED above the
switch and energises the rear window heater relay on the rear fusebox. After 10 minutes (when ambient temperature
is –15 °C (5 °F) or above) or 17 minutes (when ambient temperature is less than –15 °C (5 °F)), the ATC ECU
extinguishes the LED and operates the rear window heater at low power for 60 minutes. During the 60 minutes, the
ATC ECU cycles the rear window heater relay off for 80 seconds and on for 40 seconds. If the rear window heater
switch is pressed again during the low power phase, the ATC ECU illuminates the LED again and returns the rear
window heater to full power by keeping the rear window heater relay energised for 5 minutes. At the end of the 5
minutes the LED is extinguished and the 60 minutes low power phase is repeated.
The ATC ECU outputs a K bus message when the rear window heater is active. The message allows the navigation
computer to compensate for the effect of the magnetic field generated when the rear window heater is active. The
BCU transfers the message onto the P bus for the door modules, which activate the door mirror heaters together with
the rear window heater.
Washer Jet Heaters
The ATC ECU automatically energises the washer jets relay, on the passenger compartment fusebox, when the
ignition is on and the ambient temperature is less than 3 °C (37 °F). If the ambient temperature increases to more
than 6 °C (43 °F), the ATC ECU de-energises the washer jets relay.
Parked Ventilation
Parked ventilation is only incorporated on vehicles with a FBH system which include the parked heating function.
When the ignition switch is in position I, parked ventilation can be selected on and off using the MID or MFD. When
the ignition is off, parked ventilation can be set to come on at a programmed time. The programmed time is a start
time for parked ventilation to begin within the next 24 hours and is entered into the instrument pack using the MID/
MFD.
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-47
Once parked ventilation is on, if it is not selected off it will automatically time-out after 30 minutes. Parked ventilation
is automatically cancelled when the ignition is switched on.
At a programmed parked ventilation start time, or when parked ventilation is selected on using the MID/MFD, the
instrument pack outputs parked ventilation requests to:
l The MID/MFD on the I bus
l The ATC ECU on the K bus.
On receipt of the messages:
l A red LED on the MID/MFD panel flashes at 2 Hz to indicate that parked ventilation is active
l The ATC ECU operates the blower at speed 1, opens the face level distribution flaps in the heater assembly and
closes the windscreen and footwell flaps.
The ATC ECU disables parked ventilation if battery voltage is less than 11.4 V.
FBH System
The FBH system operates in two modes:
l Parked heating, to heat the passenger compartment while the vehicle is parked with the engine off
l Additional heating, to boost heater performance while the engine is running
The ATC ECU disables FBH operation if battery voltage is too low.
l When the engine is off the low voltage limit is 11.4 V for more than 10 seconds; the system is re-enabled if battery
voltage increases to 12.2 V
l When the engine is running the low voltage limit varies, with ambient temperature, between 11.1 V at –25 °C and
below and 11.7 V at 15 °C and above; if battery voltage is below the limit for 2 minutes the system is disabled for
the remainder of the ignition cycle.
During FBH operation, with or without the engine running, the coolant valves remain de-energised and heater matrix
temperature is directly related to the temperature of the coolant coming from the FBH unit.
Parked Heating
When the ignition switch is in position I, parked heating can be selected on and off using the MID or MFD. When the
ignition is off, parked heating can be set to come on at a programmed time or selected on and off using the remote
handset. The programmed time is a start time for parked heating to begin within the next 24 hours and is entered into
the instrument pack using the MID/MFD.
Once parked heating is on, if it is not selected off it will automatically time-out after 30 minutes. If the engine is started
while parked heating is on:
l If the engine coolant temperature is equal to or more than the heater coolant temperature, parked heating is
switched off
l If the engine coolant temperature is less than the heater coolant temperature, parked heating remains on until
the engine coolant temperature reaches the heater coolant temperature.
Programmed and MID/MFD Selected Parked Heating
At a programmed parked heating start time, or when parked heating is selected on using the MID/MFD, the instrument
pack outputs:
l A FBH request to the MID/MFD on the I bus
l A FBH request to the ATC ECU and the Body Control Unit (BCU) on the K bus
l Ambient and engine temperatures to the ATC ECU and BCU on the K bus.
On receipt of the messages:
l A red LED on the MID/MFD panel flashes at 2 Hz to indicate that parked heating is active.
l If the ambient temperature is less than 5 °C (41 °F), the BCU activates the door mirror heaters for 3 minutes
l The ATC ECU:
l Energises the changeover valve
l Sends a K bus message to activate the FBH
l Operates the blower at speed 1
l Opens the windscreen distribution flaps in the heater assembly and closes the face and footwell flaps.
AIR CONDITIONING
82-48 DESCRIPTION AND OPERATION
Heater Coolant Circuit - With FBH
1 Coolant valve (low line system)
2 Heater matrix
3 Coolant valves (high line system)
4 Auxiliary coolant pump
5 Engine cooling system
6 ATC ECU
7 Changeover valve
8 FBH unit
When parked heating is selected off using the MID/MFD, or after 30 minutes has elapsed, the instrument pack sends
FBH off messages on the I and K buses to cancel parked heating. On receipt of the messages:
l The MID/MFD switches off the LED
l The ATC ECU:
l Sends a K bus message to de-activate the FBH
l Switches off the blower
l Returns the distribution flaps to the previous settings
l After 3 minutes, de-energises the changeover valve.
M82 0820
5
6
7
8
3
2
1
2
4
AIR CONDITIONING
DESCRIPTION AND OPERATION 82-49
Remotely Selected Parked Heating
When parked heating is selected on with the remote handset, the request is received by the FBH receiver via the TV
antenna and TV receiver. The FBH receiver relays the request as a hardwired signal to the FBH ECU. On receipt of
the request, the FBH ECU sends a FBH on request to the ATC ECU on the K bus. Provided there are no system faults,
the ATC ECU then:
l Returns a FBH on request to the FBH ECU, which starts FBH operation
l Energises the changeover valve
l Operates the blower at low speed
l Opens the windscreen distribution flaps in the heater assembly and closes the face and footwell flaps
l Transmits the FBH status on the K bus to the instrument pack.
When the instrument pack receives the FBH status message, it outputs:
l A FBH request to the MID/MFD on the I bus to operate the flashing LED on the MID/MFD panel
l Ambient and engine temperatures to the ATC ECU and BCU on the K bus
l A FBH request to the BCU on the K bus. If the ambient temperature is less than 5 °C (41 °F), the BCU activates
the door mirror heaters for 3 minutes.
Additional Heating
On Td6 models, additional heating reduces the heater warm-up time and is also used to maintain heater performance
throughout the drive cycle. On V8 models, additional heating is only used to reduce the heater warm-up time at the
beginning of the drive cycle, and only occurs if parked heating is already active when the engine starts.
The ATC ECU activates the additional heating mode when the engine is running and the following conditions coexist:
l The ambient temperature is less than 5 °C (41 °F)
l The engine coolant temperature is less than 75 °C (167 °F)
l The heater coolant temperature is less than 75 °C (167 ° F)
l The reference temperature is 100%
l The blower is on.
To activate the additional heating mode, the ATC ECU energises the auxiliary coolant pump and sends K bus
messages to the FBH unit to start/continue operation (the changeover valve remains de-energised).
The ATC ECU stops the FBH and de-energises the auxiliary coolant pump when any of the following occur:
l The engine stops
l The ambient temperature increases to more than 15 °C (59 °F)
l The engine coolant temperature increases to more than 75 °C (167 °F)
l The heater coolant temperature increases to more than 75 °C (167 °F)
l The reference temperature decreases to less than 90%
l The blower is selected off.
FBH Unit
Once initiated by a message from the ATC ECU, FBH operation is controlled by the ECU in the FBH unit. The ECU
controls the FBH unit at one of two heat output levels, 2.5 kW at part load combustion and 5 kW at full load
combustion.
Start Sequence: At the beginning of the start sequence the ECU energises the glow plug function of the glow plug/
flame sensor, to preheat the combustion chamber, starts the combustion air fan at slow speed and energises the
coolant circulation pump. After approximately 30 seconds, the ECU energises the FBH fuel pump at the starting
sequence speed. The fuel delivered by the FBH fuel pump evaporates in the combustion chamber, mixes with air from
the combustion air fan and is ignited by the glow plug/flame sensor. The ECU then progressively increases the speed
of the FBH fuel pump and the combustion air fan. Once combustion is established the ECU switches the glow plug/
flame sensor from the glow plug function to the flame sensing function to monitor combustion. From the beginning of
the start sequence to stable combustion takes approximately 90 seconds for a start to part load combustion and 150
seconds for a start to full load combustion.
AIR CONDITIONING
82-50 DESCRIPTION AND OPERATION
Coolant Temperature Control: When the ECU first enters the active mode, it initiates a start to full load combustion.
Full load combustion continues until the heat exchanger casing temperature reaches 72 °C (162 °F), at this point the
ECU decreases the speed of the FBH fuel pump and the combustion air fan to half speed, to produce part load
combustion. The ECU maintains part load combustion while the heat exchanger casing temperature remains between
68 and 76 °C (154 °C and 169 °F). If the heat exchanger casing temperature decreases to 68 °C (154 °F), the ECU
switches the system to full load combustion again. If the heat exchanger casing temperature increases to 76 °C (169
°F), the ECU enters a control idle phase of operation.
On entering the control idle phase, the ECU immediately switches the FBH fuel pump off, to stop combustion, and
starts a timer for the combustion air fan. After a 2 minute cool down period, the ECU switches the combustion air fan
off and then remains in the control idle phase while the heat exchanger casing temperature remains above 71 °C (160
°F). If the heat exchanger casing temperature decreases to 71 °C (160 °F), within 15 minutes of the ECU entering the
control idle phase, the ECU initiates a start to part load combustion. If more than 15 minutes elapse before the heat
exchanger casing temperature decreases to 71 °C (1608 °F), the ECU initiates a start to full load combustion.
In order to limit the build up of carbon deposits on the glow plug/flame sensor, the ECU also enters the control idle
phase if the continuous part and/or full load combustion time exceeds 72 minutes. After the cool down period, if the
heat exchanger casing is still in the temperature range that requires additional heat, the ECU initiates an immediate
restart to part or full load combustion as appropriate.
Shutdown: When the ATC ECU sends a K bus message to de-activate the FBH operation, the ECU de-energises the
FBH fuel pump to stop combustion, but continues operation of the combustion air fan and the circulation pump to cool
down the FBH unit. The cool down time depends on the combustion load at the time the message is received.
Cool Down Times
Diagnostics: The ECU monitors the FBH system for faults. Any faults detected are stored in a volatile memory in the
ECU, which can be interrogated by Testbook/T4. A maximum of three faults and associated freeze frame data can
be stored at any one time. If a further fault is detected, the oldest fault is overwritten by the new fault.
The ECU also incorporates an error lockout mode of operation that inhibits system operation to prevent serious faults
from causing further damage to the system. In the error lockout mode, the ECU immediately stops the FBH fuel pump,
and stops the combustion air fan and circulation pump after a cool down time of approximately 2 minutes. Error lockout
occurs for start sequence failures and/or combustion flameouts, heat exchanger casing overheat and out of limit input
voltage. The error lockout mode can be cleared using Testbook, or by disconnecting the battery power supply for a
minimum of 10 seconds.
Start Failure/Flameout: If a start sequence fails to establish combustion, or a flameout occurs after combustion is
established, the ECU immediately initiates another start sequence. The start failure or flameout is also recorded by
an event timer in the ECU. The event timer is increased by one after each start failure or flameout, and decreased by
one if a subsequent start is successful. If the event timer increases to three (over any number of drive cycles), the
ECU enters the error lockout mode.
Heat Exchanger Casing Overheat: To protect the system from excessive temperatures, the ECU enters the error
lockout mode if the heat exchanger casing temperature exceeds 105 °C (221 °F).
Out of Limit Voltage: The ECU enters the error lockout mode if the battery or alternator power input is less than 10.5
± 0.3V for more than 20 seconds, or more than 15.5 ± 0.5V for more than 6 seconds.
Combustion Load Cool Down Time, Seconds
Part 100
Full 175
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-1
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WIPERS AND WASHERSDESCRIPTION AND OPERAT ION
WIPERS AND WASHERS
84-2 DESCRIPTION AND OPERATION
Wiper and Washer System Component
Location
RH drive specification shown, LH drive similar
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-3
1 Wiper linkage and motor assembly
2 Wiper arm assembly RH
3 Wiper arm assembly LH
4 Rear wiper, motor and control module
assembly
5 Wiper control switch
6 Rain sensor
7 Body Control Unit (BCU)
8 Headlamp wiper relay
9 Front wiper relay
10 Washer reservoir and pumps assembly
11 Headlamp wiper and motor assembly
12 Washer jet (2 off)
WIPERS AND WASHERS
84-4 DESCRIPTION AND OPERATION
Wipers and Washers Control Diagram
A = Hardwired; B = K Bus; C = Diagnostic DS2 Bus; K = I Bus
M84 0413A
18
19
9
6
7
3
25
24
23
22
21
20
4
2
10
11
13
15
16
17
12
14
C
A
B
K
5
8
1
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-5
1 Wiper control column switch
2 Fuse 20A
3 Front wiper relay
4 Light Check Module (LCM)
5 Fluid level sensor
6 Instrument pack
7 Rain sensor
8 Body control Unit (BCU)
9 Diagnostic socket
10 Fuse 5A
11 Ignition switch
12 Passenger compartment fusebox
13 Fuse 30A
14 HEVAC ECU
15 Heated washer jets and screen blade heater
relay
16 Heated blade screen elements
17 Heated washer jets
18 LH headlamp wiper motor
19 RH headlamp wiper motor
20 Headlamp washer pump
21 Windscreen washer pump
22 Rear screen washer pump
23 Rear wiper motor and control module
24 Headlamp wiper relay
25 Front wiper motor
WIPERS AND WASHERS
84-6 DESCRIPTION AND OPERATION
Description
General
The wipers and washers system is controlled by the Body Control Unit (BCU) on receipt of requests made by the driver
or the rain sensor unit (if fitted). All wiper functions for the front and rear wipers are controlled from a multifunction
wash/wipe switch assembly located on the right hand side of the steering column.
The wiper and washer system comprises:
l Front and rear wiper motors
l A front wiper linkage
l Two front and one rear wiper arms and blades
l Two front washer jets and one rear washer jet (incorporated with rear wiper arm)
l A washer reservoir and three pumps
l A wash/wipe control column switch.
Other items are added to enhance the wiper system:
l Heated front washer jets
l Headlamp wash/wipe system
l A rain sensor for automatic wiper control.
The wiper system can be optionally equipped with a rain sensor. The sensor, located below the interior rear view
mirror, detects rain drops on the windscreen and automatically operates the wipers in the intermittent mode. The
column stalk switch must be in the intermittent position for rain sensor controlled wiper operation.
The front wiper system has four wiper stages of operation and four intermittent wiper delay periods. The four wiper
stages are as follows:
l Flick wipe
l Intermittent
l Normal (slow) speed continuous
l Fast speed continuous.
The intermittent, normal and fast speeds are affected by road speed. The intermittent wiper delay periods change with
the road speed, with the delay decreasing as the road speed increases. The normal continuous operation changes to
intermittent operation when the vehicle is stationary. The fast speed operation changes to normal operation when the
vehicle is stationary.
The wiper and washers operate with the ignition switch in positions I or II (aux or ign). Wiper functions are suspended
during engine cranking to reduce battery power consumption under high load conditions.
+ BODY CONTROL UNIT, DESCRIPTION AND OPERATION, Description.
Diagnostic information for the wiper system is available and can be retrieved using TestBook/T4.
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-7
Wiper Control Column Switch
1 Wash/wipe control column switch
2 Intermittent delay rotary control
3 Programme wash/wipe position
4 Fast wipe position
5 Normal wipe position
6 Intermittent wipe position
7 Flick wipe position
8 Programme wash/wipe position
9 Rear wash/wipe position
10 Rear wipe position
The wiper control column switch is located on the right hand side of the steering column and controls all front and rear
wiper functions.
Moving the switch up one position selects intermittent front wiper operation. The rotary potentiometer on the stalk
selects one of four delay periods. When a rain sensor is incorporated into the system, the intermittent position also
initiates wiper operation controlled by the rain sensor. The sensitivity of the rain sensor can be adjusted by rotating
the rotary potentiometer to one of the four positions. Moving the switch up one further position selects normal (slow)
continuous wiper operation. Moving the switch up to the last position selects fast continuous wiper operation.
Moving the switch down selects the flick wipe function. The front wipers will operate at normal speed for as long as
the flick wipe switch position is operated and will stop at the park position when the switch is released.
Moving the switch rearwards, towards the driver, selects the programmed front wash/wipe function. The windscreen
washer pump will operate for as long as the switch is held. A short operation operates the pump momentarily and the
wipers complete three full cycles before stopping. When headlamp wash/wipe is fitted, the headlamp washers and
wipers will operate if programmed wash/wipe is selected and the headlamps are on. The wash/wipe function can also
be selected by depressing the button on the end of the stalk.
Moving the switch forwards to the first switch position selects the rear wiper on. The rear wiper will complete one full
cycle and will then operate on an intermittent function until selected off. The intermittent delay between wipes can be
adjusted by selecting the wiper on, then off and then on again. Moving the switch forward to the second position
selects the programmed rear wash/wipe function. The wiper completes five full cycle with three automatic, short
operations of the rear washer pump. The rear wiper then operates in the rear wiper on mode until selected off.
The rear wiper also operates continuously if reverse gear is selected and the front wipers are on.
The wiper control column switch comprises 8 switch positions and the intermittent rotary control. The switch positions
each complete a combination of earth paths to three connections on the BCU. The BCU interprets the selected
combination of switches and operates the respective function accordingly.
WIPERS AND WASHERS
84-8 DESCRIPTION AND OPERATION
Front Wipers
The front wiper system comprises:
l Wiper motor and linkage assembly
l Washer reservoir and pumps
l Wiper arms and blades.
Wiper Linkage
1 Wiper spindle cap (2 off)
2 RH pivot housing assembly
3 Link rod
4 Tube
5 Motor crank
6 Link rod
7 Crank
8 LH pivot housing assembly
9 Bush
10 Sleeve
11 Bolt
12 Sleeve
13 Bush
14 Motor assembly
15 Bracket
The wiper linkage and motor assembly are available as separate components. The wiper linkage differs between LH
and RH drive models. The wiper motor is common to LH and RH drive models.
The assembly is located below the plenum grill in the engine compartment and is secured with bushes, sleeves and
bolts. The rubber bushes isolate the assembly from the body mountings.
The linkage assembly comprises a main tube, with a pivot housing at each end. A bracket is attached, offset along
the tube length, which locates the motor assembly. A motor crank is positively attached to the motor output shaft. A
link rod is connected to the motor crank and is connected at the opposite end to the RH pivot housing, via a crank.
The RH link rod has a pivot attachment for the LH link rod, which is connected at its opposite end to the RH pivot
housing, via a second crank.
The motor crank converts rotary motion from the motor output shaft into linear movement of the link rods. The cranks,
connected between the each link rod and pivot housing, convert the linear motion back to rotary motion of the pivot
housing. This rotary motion is passed to the wiper arms and blades causing the blades to wipe an arc across the
windscreen.
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-9
Wiper Motor
The motor assembly comprises a dc motor which drives a gear wheel via a worm drive attached to the motor spindle.
The gear wheel has a central spigot which provides the attachment point for the motor crank.
The motor is connected electrically by a four pin connector. The connector supplies two battery voltage feeds to the
motor. The motor has three sets of brushes with one brush connected to ground. One feed is direct to the motor brush
opposite the ground brush and operates the motor at normal (slow) speed. The second feed is connected to a motor
brush which is offset from the ground brush and operates the motor at fast speed. With the power supplied through
this brush, the current flows through fewer coil windings. This results in a lower resistance to the current flow to the
ground brush and gives a higher motor rotational speed.
Output control of the wiper motor is through a double contact relay. The relay is located in the engine compartment,
adjacent to the transfer box ECU, behind the battery. The relay is a tan colour for identification.
The motor has an internal track which signals the BCU when the wipers have reached the park position. The park
signal is an open circuit when the wipers are in the park position. When the wipers are switched off and the BCU
receives the park position signal from the motor, the BCU shorts the motor via a relay bridge circuit. This short circuit
has the effect of applying a brake to the motor, giving precise positioning of the wiper blades in the park position.
Wiper Arms
1 Blade locking clip
2 Wiper arm collet
3 Wiper arm
4 Spindle cap
5 Self locking nut
6 Wiper angle adjust shim
7 Wiper angle adjuster
8 Wiper blade
9 Air deflector
WIPERS AND WASHERS
84-10 DESCRIPTION AND OPERATION
The wiper arms are positively located on tapered splines on the wiper linkage spindles. The arm is located on a curved
wiper angle adjuster, which mates with the curved underside of the arm attachment. A curved slot in the arm
attachment locates an adjustment shim and the three components are retained under compression on the spindle
spline by a self locking nut.
The wiper angle adjuster and the angle adjust shim allow the approach angle of the wiper blade to be finely adjusted
to its optimum wiping angle. The adjustment allows the approach angle of the blade to adjusted to 2° on each side of
the spindle axis. This adjustment provides precise adjustment of the blade approach angle for maximum wiper
performance. The wiper angle adjuster is pressed onto the spindle and requires a tool for removal. Once removed,
the wiper angle adjuster must be discarded and new one fitted on re-assembly.
The wiper arm has a pivot point, midway between the spindle attachment and the blade. Two tension springs are
connected to the wiper arm on each side of the pivot point and apply pressure to maintain the wiper blade in contact
with the windscreen.
The wiper blades are attached to the wiper arms with clips that allow the blade to pivot. Each blade comprises a
number of levers and yokes to which the rubber wiper blade is attached. The levers and yokes ensure that the
pressure applied by the arm tension spring is distributed evenly along the full length of the blade and also allow the
blade to adjust to the curvature and contour of the windscreen. The drivers side blade is fitted with an aerofoil which
presses the blade onto the windscreen at high speed, improving the wiper performance.
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-11
Washer Reservoir and Pumps
1 Breather tube
2 Reservoir
3 Rear washer pump
4 Front washer pump
5 Headlamp washer pump
6 Fluid level sensor
7 Filler tube and cap
The windscreen washer system comprises a reservoir, a washer pump, two washer jets and hoses.
The plastic, moulded reservoir is located in the LH wheel arch, behind the liner and has a capacity of 8.8 pints (5 litres).
It is secured to the body and front panel with bolts and washers. A boss on the reservoir locates in a slot in the front
panel and provides additional support.
The reservoir has three recessed holes on its rear face which provide location for the front, rear and headlamp washer
pumps. The pumps are push fitted into grommets which seal the pumps in their locations. A hole in the top of the
reservoir allows for the fitment of a flexible filler tube. The hose is routed into the left hand side of the engine
compartment and is sealed with a rubber cap. A breather hose is fitted into an elbow on the top of the reservoir and
is routed alongside the filler and secured in a clip near the filler cap in the engine compartment.
A hole in the base of the reservoir provides the location for the fluid level sensor. The hole provides access to an
internal tube in side the reservoir, into which the sensor is fitted. The sensor has two pegs which positively locate the
sensor in the reservoir when turned through 90°.
WIPERS AND WASHERS
84-12 DESCRIPTION AND OPERATION
The sensor reacts to the influence of a magnetic field. A float, with integral magnet, is located around the tube, inside
the reservoir. The sensor has two contacts, inside a glass tube, which are normally open. When the fluid level reduces,
the magnetic float moves down the tube. When the magnet reaches the sensor contacts, the magnetic field closes
the contacts. This completed circuit is sensed by the LCM which displays the low fluid level message in the instrument
pack.
Heated Windscreen Washer Jets
Two windscreen washer jets are located in the rear trim panel on the bonnet outer surface. The washer fluid feed hose
from the front screen pump is connected to a 'Y' piece connector located between the two jets. Two short lengths of
hose connect the jets to the 'Y' piece. Each jet contains a non-return valve (NRV) to prevent washer fluid draining
back to the reservoir and also to limit the amount of washer fluid which can be forced by gravity from the jet during
cornering.
Each washer jet has two ball nozzles which can rotate in their housings to obtain the optimum fluid application onto
the windscreen. Each washer jet contains a heater element which prevents the fluid freezing in the nozzles in very
cold conditions. The jet heater elements are controlled by the Automatic Temperature Control (ATC) system, which
energises the heater elements when the ambient temperature falls below a predetermined temperature.
Wiper Blade Heating
The lower, black, portion of the windscreen contains six heating elements which run from one side of the screen to
the other. These elements are designed to heat the area of the windscreen where the wiper blades rest to prevent
freezing in cold conditions.
The blade heating elements are controlled by the ATC system, which energises the blade heating elements when the
ambient temperature falls below a predetermined temperature. The operation of the blade heating elements is
activated simultaneously with the heated washer jets.
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-13
Rain Sensor
1 Transmitter diodes
2 Retaining clip (2 off)
3 Connector
4 Receiver diodes
5 Light sensor
6 Latch clip (4 off)
7 Heater element
8 Rain sensor body
The rain sensor is located at the upper edge of the windscreen, behind the interior rear view mirror. The sensor is
mounted on an optical unit which is heat bonded to the inner surface of the windscreen during manufacture. If damage
occurs to the optical unit or the windscreen, then a new windscreen will be required and fitment can only be performed
by an authorised Land Rover dealer.
The rain sensor unit attaches to the optical unit via four clips which latch onto formed tags on the optical unit. Positive
retention is achieved by two retaining clips which force the clips onto the tags. The retaining clips must be withdrawn
to facilitate sensor removal.
The sensor provides information to the BCU, via the K bus, for the optimum wiper operation for the prevailing
conditions to maintain the screen in a clear condition at all times. The rain sensor is an optical unit which operates on
an infrared waveband. The sensor uses the principle of the laws of reflection on interfacing surfaces between
materials with differing refraction indices.
WIPERS AND WASHERS
84-14 DESCRIPTION AND OPERATION
Rain Sensor Functionality
A. = Clean and dry windscreen; B. = Wet and dirty windscreen
1 Windscreen - Outside surface
2 Optical unit
3 Transmitter diodes (100% light transmitted)
4 Rain sensor unit
5 Receiver diodes (100% received)
6 Water droplets/film
7 Receiver diodes (less than 100% light
received)
8 Lost light
The rain sensor contains transmitter and receiver diodes which transmit and receive infrared light which is directed
onto the windscreen via an optical unit. The light is directed at an angle so that the light is reflected 100% on the
outside surface of the screen and is transmitted back into the optical unit. To receive a 100% reflection, the outer
screen surface must be clean and dry.
The light is reflected four times from when it leaves the transmitter diodes to when it is picked up by the receiver
diodes. If the windscreen is wet or dirty in the area of the optical unit, the clean conditions for 100% reflection means
that some of the light reflected is lost. As the screen becomes dirtier or wetter, the received light is evaluated by the
rain sensor and translated into a signal value. A micro-controller within the sensor monitors the change in signal and
initiates the appropriate wipe cycle via K bus signals to the BCU.
The software can compensate for the long term effects of scratches and stone chips in the area of the optical unit and
the short term effects of dirt or smears caused by worn wiper blades. A heater element is also contained within the
rain sensor and uses ambient temperature K bus signals from the instrument pack to keep the optical unit clear of
frost or condensation.
A light sensor is incorporated into the sensor and is used to increase the sensitivity of the sensor when light levels are
low. This feature counteracts the effects of rain on the windscreen affecting the driver's vision during night time driving.
M84 0421
1
5
A
4
3
2
4
6
1
3
2
8
7
B
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-15
Rear Wiper
The rear wiper system comprises:
l Wiper motor and control module assembly
l Rear washer pump
l Wiper arm and blade.
Wiper Motor
1 Harness connectors and control module
2 Washer fluid hose connection
3 Mounting bracket
4 Non-return valve (NRV)
5 Motor
6 Wiper blade
7 Wiper arm
8 Torx head screw (3 off)
The rear wiper and washers operation is controlled by the control module which is located with the rear wiper motor.
The rear wiper operation is remote from the BCU control of the front wiper systems.
The rear wiper motor and control module assembly is located in the upper tail door, behind a trim panel. The assembly
is secured to a bracket on the upper tail door with three, Torx head screws. Rubber bushes isolate the motor assembly
from the bracket, which help reduce the transmission of motor operating noise to the tail door.
The assembly comprises the motor, mounting bracket and control module. The motor is located on a worm drive
gearbox mechanism which converts the rotary motion of the motor output spindle into the required arc for the rear
wiper blade. The control module is integral with the motor and has two plug sockets which accept two multiplugs from
the harness. One multiplug has 2.5 mm diameter wires. Two of the wires supply permanent battery feed and ground
connections for the motor and control module. The third wire in this plug supplies a power supply to the rear washer
pump. The second multiplug has 0.35 mm diameter wires and carries signal data from the wash/wipe control stalk
switch and the LCM and also a power input from the passenger compartment fusebox.
The rear washer feed hose is located at the rear of the motor spindle. The hose is connected to a 90° connector
allowing the washer fluid to flow through the centre of the motor spindle. An NRV is located in the hose, near the
motor, and prevents fluid returning to the reservoir.
WIPERS AND WASHERS
84-16 DESCRIPTION AND OPERATION
The motor spindle is a conventional design with a taper spline location for the wiper arm and a threaded shank to
secure the arm to the spindle.
Wiper Arm
The wiper arm is similar in design to the front wiper arms. The arm attachment hole has tapered splines which mate
with the splines on the wiper spindle. The arm is secured to the wiper motor spindle with a spring washer and nut. The
wiper arm has a pivot point, close to the spindle attachment. A tension spring is connected to the wiper arm on each
side of the pivot point and applies pressure to maintain the wiper blade in contact with the windscreen.
The wiper blade is attached to the wiper arm with a clip that allows the blade to pivot. The blade comprises a number
of levers and yokes to which the rubber wiper blade is attached. The levers and yokes ensure that the pressure
applied by the arm tension spring is distributed evenly along the full length of the blade and also allow the blade to
adjust to the curvature and contour of the windscreen.
A plastic cap located on the arm pivot point, covers the spindle attachment nut. The cap also contains two, adjustable
ball jets, which direct washer fluid onto the tail door window. The cap, when installed, connects with the hollow motor
spindle, through which the washer fluid flows to the jets.
Headlamp Wipers
1 Wiper blade
2 Electrical connector
3 Mounting bracket
4 Washer hose connection
5 Motor assembly
6 Mounting bolt (2 off)
7 Cover and jet
8 Nut
9 Wiper arm
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-17
The headlamp wiper assembly is located below each headlamp. The assemblies are handed and therefore are not
interchangeable. Each assembly is located on a bracket which is secured to the front panel and the headlamp. The
motor is secured to the bracket with two bolts.
The headlamp wiper operation is controlled by the BCU via a headlamp wiper relay. The relay is located behind the
fascia. The relay is attached to the air suspension ECU mounting bracket, above the passenger compartment fusebox
and can be identified by its black colour.
A 90° connector at the rear of the motor allows for the attachment of the washer fluid hose from the headlamp washer
pump. The washer fluid is directed through the centre of the motor drive spindle and supplies a washer jet in the
spindle cover.
The motor drives a gearbox which drives the wiper blade across the headlamp in an arc. The motor spindle protrudes
through a finisher below the headlamp. A tapered spline provides positive location for the wiper arm which is secured
to the spindle by a nut.
The wiper arm attachment hole has tapered splines which mate with the splines on the motor spindle. The wiper arm
has a pivot point, close to the spindle attachment. A tension spring is connected to the wiper arm on each side of the
pivot point and applies pressure to maintain the wiper blade in contact with the headlamp lens.
A plastic cap, located on the arm pivot point, covers the spindle attachment nut. The cap also contains an adjustable
ball jet, which directs washer fluid onto the headlamp lens. The cap, when installed, connects and seals onto the
hollow motor spindle, through which the washer fluid flows to the jets.
The wiper blade is attached to the wiper arm with a clip that allows the blade to pivot. The blade comprises two yokes
to which the rubber wiper blade is attached. The yokes ensure that the pressure applied by the arm tension spring is
distributed evenly along the full length of the blade.
WIPERS AND WASHERS
84-18 DESCRIPTION AND OPERATION
Operation
Front Wipers
The front wiper system has the following functionality:
l Intermittent wipe and delay adjustment
l Normal (slow) speed wipe
l Fast speed wipe
l Programme wash/wipe
l Flick wipe
l Headlamp powerwash (if fitted)
l Motor blocking protection.
Intermittent
Intermittent wiper operation is selected on the wiper control column switch, by moving the switch vertically, to the first
position. The intermittent delay period is adjustable using the rotary switch on the wiper control column switch. The
delay period is also subject to vehicle speed, with the selected delay period decreasing with an increase in road
speed.
The rotary potentiometer selects differing resistance values for each position. The potentiometer is connected into a
voltage divider circuit, with a 6.8kΩ resistor located in the BCU. The power supply to the voltage divider circuit is
limited to 6.5V. This reduced voltage is used by the BCU to determine the position of the rotary switch as follows:
The intermittent delay is also influenced by the road speed of the vehicle using a signal value derived from the ABS
ECU on the K bus. The delay periods for the vehicle stationary and when moving at different vehicle speeds are shown
in the following table:
The rotary switch positions also influence the operation of the rain sensor (when fitted) by adjusting its sensitivity.
Refer to the following Rain Sensor operation section for details.
Normal (Slow) Speed
The normal (slow) speed continuous wiper operation is selected by moving the switch vertically to the second detente
position. The wipers will operate continuously when the vehicle is moving. When the vehicle is stationary (less than
4 mph (6 km/h)), the BCU operates the wipers in the intermittent mode, using a 3 second intermittent delay period for
NAS and Australian market vehicles and a 5 second intermittent delay period for ROW vehicles.
Rotary Switch
Position
Resistance Voltage
Min Max Typical
Error - Ground <0.2kΩ - - <0.18V
12kΩ ± 750Ω 1.00V 1.89V 1.48V
24kΩ ± 750Ω 2.08V 2.70V 2.41V
36kΩ ± 750Ω 2.80V 3.27V 3.04V
48kΩ ± 750Ω 3.32V 3.69V 3.51V
Error - Positive >20kΩ --4.88V
Rotary Switch
Position
Vehicle Speed mph (km/h)
4
(6)
4 - 19
(6 - 30)
19 - 44
(30 - 70)
44 - 62
(70 - 100)
62 - 87
(100 - 140)
>87
(140)
>112
(180)
Time Delay (seconds)
Error - Ground 20 6 5 4 3 3 3
1 261917151513 13
2 17121110 9 7 7
310665433
45332222
Error - Positive 8 6 5 4 3 3 3
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-19
Fast Speed
The fast speed continuous wiper operation is selected by moving the switch vertically to the third detente position.
The wipers will operate continuously at fast speed when the vehicle is moving. When the vehicle is stationary (less
than 4 mph (6 km/h)), the BCU operates the wipers in normal (slow) speed mode
Rain Sensor
The rain sensor is active when the wiper column control switch is in the intermittent position. The rain sensor suspends
wiper operation when the area of the windscreen for the rain sensor is dry and operates the wipers continuously when
the windscreen is subject to heavy rainfall.
If the ignition is switched off and the wiper column control switch remains in the intermittent position, the BCU will
suspend rain sensor operation until intermittent operation is reselected, an adjustment of the rotary switch is made or
programmed wash/wipe is selected.
The sensitivity of the rain sensor can be adjusted by the driver using the intermittent rotary switch on the wiper stalk.
Four sensitivity levels of the sensor can be selected which has the effect of increasing or decreasing the wiper delay
period, allow driver adjustment for the prevailing conditions. When several continuous wipe cycles have taken place,
the sensor will maintain the continuous operation to avoid switching back to intermittent from a continuous wipe and
back again.
The rain sensor receives vehicle speed information from the ABS ECU via the instrument pack on the K bus every
two seconds. The sensor increases the sensitivity as the speed increases to optimise wiper operation. When the
vehicle speed is reduced to less than 5 mph (8 km/h), the sensitivity is automatically reduced. Below this speed the
wipers will only operate continuously in very heavy rain.
Wash/Wipe
Wash/wipe is selected by moving the wiper column control switch rearwards. This switch position is non-latching and
the windscreen washer pump is operated for as long as the switch is active. If the switch is only momentarily operated
(less than 300 ms), only the washer pump operates. If the switch is activated for more than 300 ms, the BCU also
powers the wiper motor after a 0.5 second delay. The BCU monitors the wash/wipe switch operation and after the
switch is released, the BCU allows three full wipe cycles to clear the screen.
Reservoir Level Sensor
The sensor cannot determine the precise amount of fluid in the reservoir, but can detect when the fluid level has fallen
below a certain point. When the fluid level is low, the magnetic float closes the sensor contacts, completing a circuit
through the sensor. This completed circuit is sensed by the Light Check Module (LCM), to which the sensor is directly
connected.
The fluid level sensor is monitored continuously by the LCM. The LCM checks the fluid level sensor when the ignition
is switched on to give the driver an early warning of the low fluid level. The LCM then monitors the sensor value over
a 25 second period when the ignition is on to prevent invalid messages due to fluid 'sloshing' in the reservoir.
When the LCM determines a low fluid level signal, a telegram is transmitted on the I bus to the instrument pack to
illuminate the “WASHER FLUID LOW” message in the instrument pack message centre. The first illumination of this
message is accompanied by a 'gong' sound to alert the driver to the low fluid level.
WIPERS AND WASHERS
84-20 DESCRIPTION AND OPERATION
Heated Windscreen Washer Jets
The heated washer jets are controlled by the ATC system and a heated washer jet relay in the passenger
compartment fusebox. The ATC receives ambient temperature from the instrument pack on the K bus.
When the ignition is switched on and the ATC system detects an ambient temperature of less than 3°C (37°F), the
ATC system completes an earth path for the coil of the heated washer jet relay. This allows battery voltage to pass
through the relay contacts and operate the heater elements. The ATC maintains the power to the heater elements for
as long as the ignition remains on or the ambient temperature remains below 6°C (42°F). If the ambient temperature
increases to 6°C (42°F) or above, the ATC system removes the earth for the relay coil, de-energising the heater
elements.
The ATC system will also prevent heated washer jet operation if the battery voltage falls to below 11.4V. This is to
relieve loads on the battery and alternator when electrical loads are high. Heated washer jet operation will be resumed
when the battery voltage exceeds 12.2V.
Wiper Motor Blocking Protection
The wiper park signal is also used by the BCU for blocking protection of the front wiper motor. This feature protects
the motor in the event of the wiper operation being obstructed.
If the BCU does not receive the wiper park signal for a period of 16 seconds, when the wiper motor is active, the BCU
removes the power supply to the motor. The motor is disabled for a period of 3 minutes or until the ignition is switched
off and on again. Even after the 3 minute period has elapsed, the BCU will not automatically switch the motor on, to
prevent the risk of injury. The wiper switch must be moved off and then on to reactivate the wiper motor. The blocking
protection is active in all wiper switch positions and can only be reset by turning the ignition off.
Rear Wipers
The rear wiper has the following functionality:
l Intermittent operation
l Adjustable intermittent wipe period
l Continuous reverse wipe function.
Wiper Operation
The rear wiper is operated by the wiper column control switch. Pushing the switch forward to the first latching position
switches on the rear wiper. Moving the switch forward again to the non-latching position operates the rear wash/wipe
function.
When the rear wiper is selected on, the wiper is operated in an intermittent mode, performing one complete wipe cycle
at regular intervals. When reverse gear is engaged the rear wiper control module receives a reverse signal from the
LCM. If the rear wiper is on, the control module operates the rear wiper continuously. The continuous wipe will
continue until, reverse gear is disengaged or the rear wiper is switched off.
When rear wash/wipe is selected, the control module powers the washer pump for as long as the switch is held. When
the switch is released, the control module initiates five complete wipe cycles. The first three wipe cycles are each
accompanied by a 0.5 second operation of the rear washer pump. The final two cycles are to clear the tail door window
and do not have a washer pump operation. If intermittent remains selected, the rear wiper continues in intermittent
mode.
Intermittent Adjustment
The intermittent interval time of the rear wiper can be adjusted by the driver to wipe at between 1 and 30 second
delays. Adjustment is performed by switching the rear wiper on for a short time and then off again. The next switching
on of the rear wiper determines the delay period. The time lapse between the off and the next on signal is sensed by
the control module which sets this period as the requested time interval between wipes. If the next on signal is more
than 30 seconds after the off signal, the control module sets the time interval to the maximum 30 seconds.
Rear Wiper Motor Blocking Protection
The rear wiper control module contains similar logic to the BCU to protect the rear wiper motor in the event of the
wiper operation being obstructed.
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-21
Headlamp Wipers and Washers
The headlamp wipers and washers are only active when the headlamps are switched on and the ignition is on. The
wipers and washers are controlled by the BCU which limits their operation to preserve washer fluid in the reservoir.
With the ignition and lights on, headlamp wash/wipe is activated on the first operation of the wiper column control
switch in the wash/wipe position. The BCU then suspends headlamp wash/wipe activation for the next four operations
of the wash/wipe switch, with the headlamp wipers and washer activated on the fifth operation of the switch.
The BCU monitors the operation of the wash/wipe switch and maintains a counter to restrict headlamp wiper and
washer operation to every fifth operation of the wash/wipe switch. The BCU also maintains a timer which prevents a
second operation of the headlamp wipers and washers within a 3 minute period. The counter and timer are reset when
the ignition is switched off.
When headlamp wash/wipe is active, the BCU energises the washer pump twice per cycle. The headlamp washer
pump is powered for a 0.5 second period, 300 ms before the wiper motor starts. The BCU then initiates a 2 second
delay before powering the headlamp washer pump for a second 0.5 second period.
If the washer reservoir fluid level becomes low, the LCM, which monitors the fluid level, sends a message, via the I
bus, instrument pack and K bus, to the BCU which suspends headlamp wash/wipe operation to preserve the
remaining washer fluid.
Diagnostics
LHD model shown
1 Cover 2 Diagnostic socket
The diagnostic socket allows the transfer of information between the BCU, the rain sensor and TestBook/T4. The
diagnostic socket is located in the fascia, in the driver's side stowage tray. The socket is secured in the fascia and
protected by a hinged cover.
WIPERS AND WASHERS
84-22 DESCRIPTION AND OPERATION
The rain sensor can store fault codes which can be used to diagnose faults or non-function of the rain sensor. The
faults are stored in a non-volatile memory which retains the logged fault codes even when the power supply is
disconnected. If a rain sensor fault prevents the sensor from operating, the BCU will control wiper operation as if a
rain sensor is not installed in the system.
The BCU monitors all inputs and outputs relative to the wiper system and other BCU controlled functions. If a fault is
detected, a code applicable to that fault is stored in a fault log. Two fault logs are provided within the BCU for internal
and external faults. The BCU is capable of detecting open and short circuits and also incorrect K bus messages.
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-1
CHARGING AND STARTINGDESCRIPTION AND OPERATION
Charging and Starting Component
Location – Td6
1 Alternator 2 Starter motor
M86 5974
1
2
CHARGING AND STARTING
86-1-2 DESCRIPTION AND OPERATION
Charging and Starting Component
Location – V8
1 Alternator 2 Starter motor
M86 5975
1
2
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-3
Description
Charging and Starting System
The starting system on the vehicle comprises a 12V starter motor which drives the engine to start the combustion
process. The starter converts electrical energy into mechanical power. The vehicle electrical system must be capable
of supplying sufficient power to enable the engine to be cranked.
The charging system comprises a battery and an alternator. The battery must be of sufficient capacity to operate the
starter motor and operate the various vehicle electrical systems. The alternator charges the battery when the engine
is running and increases its output as demand on the battery increases.
The instrument pack incorporates a charge warning lamp which illuminates if the there is a low output or no output
from the alternator.
Alternator
The alternators used on the Td6 and V8 engines are different in construction, but their principles of operation are
similar. The alternator used on the V8 engine is located in a water cooled housing.
The alternators comprise a stator, a rotor, a rectifier pack and a regulator. A single output terminal is connected by a
heavy duty cable to the battery positive terminal, via the starter motor battery connection terminal. The alternator is
connected to earth via its mountings.
The rotor comprises a field winding, wound around an iron core and mounted on a shaft. The iron core has extensions
at each end which form North and South poles as current flows through the field winding. The rotor is located inside
the stator and is mounted on bearings for smooth running and to support the rotor due to the high side loading applied
by the drive belt tension.
The stator has three sets of coils made from copper wire. The three coil windings are connected in a 'star' connection,
where one end of the winding is connected to the other two windings. The output current is supplied from the opposite
end of each winding. Rotation of the rotor causes ac current to be produced in the coils.
The rectifier converts the ac current produced in the stator coils into dc (rectified) current required by the vehicle
electrical system. The rectifier comprises semi-conductor diodes mounted on a heatsink to dissipate heat. An equal
number of the diodes are on the negative and positive side, with the remaining diodes staying neutral. The rectifier
also prevents current flow from the battery to the alternator when the output voltage is less than the battery voltage.
The integrated regulator controls the output voltage from the alternator to prevent the battery from being overcharged
and to prevent the vehicle electrical systems from excessive voltage. The regulator, which is temperature related to
optimise battery charging, sets the maximum output voltage to a nominal 14.5V and varies the output voltage
depending on the state of charge of the battery and the loads required by the vehicle electrical systems.
The regulator has transistors which rapidly switch on and off to regulate the voltage output according to the voltage
sensed internally. The regulator also provides a signal output to the ECM which uses the signal to adjust the idle
speed under varying electrical loads.
Initially, the ignition switch supply provides an excitation current to the rotor at low alternator speeds via brushes which
contact slip rings at the end of the rotor shaft. As the alternator speed increases the alternator becomes self exciting.
CHARGING AND STARTING
86-1-4 DESCRIPTION AND OPERATION
Td6 Alternator
The alternator is located at the front LH side of the engine, below the steering pump. The alternator has an output of
90/150 Amps and is manufactured by Valeo. A polyvee belt drives the alternator pulley, which in turn is driven from
the engine crankshaft pulley.
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-5
V8 Alternator
The alternator is located at the front LH side of the engine. The alternator has an output of 90/150 Amps and is
manufactured by Bosch. A polyvee belt drives the alternator pulley, which in turn is driven from the engine crankshaft
pulley.
CHARGING AND STARTING
86-1-6 DESCRIPTION AND OPERATION
Starter Motor
The starter motors used on the Td6 and V8 engine are different in their construction, but their principles of operation
are similar.
Both starter motors are of conventional design with the motor in line with the drive pinion and the solenoid mounted
above. Each starter motor is of the pre-engaged type and comprises of a series wound motor, an overunning clutch
and an integral solenoid. The starter solenoid is energised by a signal from the immobilisation ECU when the ignition
switch is moved to the crank position. When engine cranking is requested, the immobilisation ECU checks that a valid
key code has been received before granting the crank request. The power for starter operation is supplied on a
substantial single cable connected direct from the battery positive terminal. The cable is connected to the solenoid via
a copper threaded stud and secured with a nut.
Td6 Starter Motor
The starter motor is located on the rear LH side of the engine block. The motor is secured to the block and protrudes
through an aperture to drive the flywheel via a ring gear.
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-7
V8 Starter Motor
The starter motor is located on the rear RH side of the engine block. The motor is secured to the block and protrudes
through an aperture to drive the flywheel via a ring gear.
Battery
The battery is located between the bulkhead and the secondary bulkhead, on the passenger side. The battery is
located in a tray and secured with clamp plates and bolts.
The battery terminal posts allow for the battery cables to be connected with clamp type connections. The battery
positive terminal uses a pyrotechnic attachment which detaches the battery cable in the event of a crash of a severity
to trigger the airbags.
+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description.
Battery Fitment Table
All models are fitted with lead-calcium, maintenance free battery. Each battery is identical in its construction with only
the battery rating differing to compensate for the different output requirements for models variants.
The battery uses 'calcium expanded' technology which has both positive and negative plates with grids expanded
from a strip lead-calcium alloy. This technology provides improved durability of the mechanical integrity of the plate
packs and reduces water loss when compared to previous technologies.
The battery is fully sealed. Each casing has a vent to allow for thermal expansion and to vent oxygen and hydrogen
gases which are produced should the battery become overcharged.
Battery Type V8 Models Td6 Models
90Ah/720A Yes (with standard
equipment levels)
No
95Ah/800A No Yes (with standard
equipment levels)
110Ah/850A Yes (with optional
equipment)
Yes (with optional
equipment)
CHARGING AND STARTING
86-1-8 DESCRIPTION AND OPERATION
The battery incorporates an integral, temperature compensated hydrometer to provide a visual indication of the
relative density and level of the electrolyte. The indicator shows different colours to show battery condition as follows:
l GREEN – shows that the battery is charged and in a serviceable condition
l DARK (turning to black) – shows that the battery is in a low state of charge and requires recharging
l CLEAR or YELLOW – the battery is no longer serviceable and must be replaced.
If the battery shows CLEAR or YELLOW the battery has an internal fault. Do not attempt to charge or jump start the
vehicle with the battery in this condition.
When removing the battery, ensure that the alarm is disarmed and that the ignition is switched off. Always disconnect
the negative terminal first and then the positive terminal. When refitting the battery, always fit the positive terminal first
followed by the negative terminal.
If the battery requires recharging, always use an approved constant current charger, designed for lead-calcium
batteries. DO NOT use a fast charger, permanent damage to the battery may occur.
Fuseboxes
Fuses are mounted in one of three fuse boxes:
l The engine compartment fusebox
l The passenger compartment fusebox
l The rear fusebox.
Some additional fusible links are mounted in the engine compartment, on the bulkhead behind the battery.
The lighting circuits are not protected by conventional fuses. MOSFETS within the Light Check Module (LCM) protect
the lighting circuits.
+ LIGHTING, DESCRIPTION AND OPERATION, Description.
Three different types of fuse are used on the vehicle:
l Blade type fuse; Small, pull out, male fuse, used to protect circuits from 5 A to 30 A.
l Maxi fuse; A larger version of the blade type fuse. Used to protect circuits at 50 A.
l Fusible links; These are bolt down fuses used to protect circuits from 50 A to 100 A.
Engine Compartment Fusebox
The engine compartment fuse box contains blade type fuses only. The fusebox is a small, grey coloured box located
within the E-box in the engine compartment.
Rear Fusebox
The rear fuse box contains blade type fuses and maxi-fuses. The fusebox is located in the right hand side of the
luggage compartment, behind the removal trim panel. The fusebox also houses relays and provides locations for
some ECU's.
Passenger Compartment Fusebox
The passenger compartment fusebox contains blade type fuses, maxi fuses and fusible links. The fusebox is located
at the rear of the glovebox. A removable panel in the rear of the glovebox allows access to the blade type fuses and
the maxi fuses. Access to the fusible links and relays, which are also located on the fusebox, requires the removal of
the glovebox assembly.
Bulkhead Mounted Fusible Links
Three fusible links are located in a plastic box on the bulkhead behind the battery.
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-9
Relay Locations
The relay locations are shown below.
Passenger Compartment Fusebox Relays
1 Heated washer jets and wiper heater relay
2 Electric seats relay
3 Not used
4 Horn relay
5 Door/Approach lamps relay
6 Steering wheel heater relay
Rear Fusebox Relays
1 Cigar lighter relay (where fitted)
2 Rear blower relay
3 Lower tail door release relay
4 Air suspension supply unit relay
5 Fuel pump relay
6 Rear seat heaters relay
7 Heated rear window relay
CHARGING AND STARTING
86-1-10 DESCRIPTION AND OPERATION
Engine Compartment E-Box Relays and Fuses
1 Ignition coil relay (V8 only)
2 Glow plugs relay (Td6 only)
3 Secondary air injection pump relay (V8 only)
4 Engine compartment fusebox
5 Main relay
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-11
Engine Compartment Bulkhead Relays and Fusible Links
1 Transfer box supply fusible link
2 Glow plug relay supply fusible link (Td6 only)
3 Main relay supply fusible link (Td6 only)
4 Starter motor relay (V8 only)
5 Windscreen wipers relay
CHARGING AND STARTING
86-1-12 DESCRIPTION AND OPERATION
Passenger Side Fascia Relays
1 Headlamp wash/wipe relay 2 Heated windscreen relay
ECU Locations
The following table shows locations for the various electronic control units used on the vehicle.
Electronic Control Unit Location Handed Yes/No
Engine Control Module (ECM) In E-Box in engine compartment No
Electronic Automatic
Transmission (EAT) ECU
In E-Box in engine compartment No
Transfer Box ECU On bulkhead in engine compartment,
behind vehicle battery
Yes
Air Suspension ECU Behind passenger side of fascia Yes
Anti-lock Brake System (ABS)
ECU
Left hand side of engine compartment No
Automatic Temperature Control
(ATC) ECU
Part of heating control panel in centre of
fascia
No
Steering Wheel Heating ECU Located in steering wheel, next to the
airbag
No
Body control Unit (BCU) Under front passenger seat Yes
Light Check Module (LCM) Right hand 'A' post, behind trim panel No
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-13
Immobilisation ECU Next to transmission selector lever
assembly on driver's side
Yes
Automatic Headlamp Levelling
ECU
Base of left hand 'A' post No
Restraint system Diagnostic
Control Unit (DCU)
Under centre console, next to handbrake No
Trailer Module On rear fusebox in right hand side of
luggage compartment
No
Tyre Pressure Monitoring ECU Under front passenger seat, below BCU Yes
Park Distance Control ECU On rear fusebox in right hand side of
luggage compartment
No
Fuel Burning Heater (FBH) ECU On fuel burning heater unit in rear of
front wheel arch on passenger side
Yes
Navigation Computer On left hand side of luggage
compartment
No
Seat Memory ECU On outside panel of driver's seat with
switch pack
Yes
Rain Sensor On inside surface of windscreen, behind
rear view mirror
No
Steering Angle Sensor On lower section of upper steering
column assembly
Yes
Rear Wiper Module On rear wiper motor assembly No
Voice Recognition ECU On left hand side of luggage
compartment, under navigation
computer
No
Telephone ECU On left hand side of luggage
compartment
No
Instrument Pack In fascia, on driver's side Yes
Drivers Door Module In top of driver's door, behind trim panel Yes
Passenger Door Module In top of passenger door, behind trim
panel
Yes
Sunroof ECU Behind headlining with motor, at forward
edge of sunroof
Xenon Headlamp Control Module Located on rear of each front Xenon
headlamp unit
No
Electronic Control Unit Location Handed Yes/No
CHARGING AND STARTING
86-1-14 DESCRIPTION AND OPERATION
Harness Routing
The following diagrams show the vehicle harnesses and routing.
1 Antenna harness
2 Audio/Video/Navigation harness
3 Door harness – rear
4 Door harness – front
M86 5870
1
2
3
4
CHARGING AND STARTING
DESCRIPTION AND OPERATION 86-1-15
1 Tail door harness
2 Main harness
3 Engine bay harness
4 Passenger compartment harness
5 Rear bumper harness
M86 5871A
1
2
3
4
5
CHARGING AND STARTING
86-1-16 DESCRIPTION AND OPERATION
1 Tail door harness
2 Main harness
3 Passenger compartment harness
4 Rear bumper harness
5 Telephone harness
M86 5872A
1
2
3
4
5
LIGHTING
DESCRIPTION AND OPERATION 86-2-1
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LIGHTINGDESCRIPTION AND OPERATION
LIGHTING
86-2-2 DESCRIPTION AND OPERATION
Exterior Lighting Component Location
M86 5848
1
2
3
12
8
13
4
6
5
16
15
14
7
10
11
9
LIGHTING
DESCRIPTION AND OPERATION 86-2-3
1 Light Check Module (LCM)
2 Light control switch
3 LH Column switch
4 Direction indicator side repeater
5 Front direction indicator
6 Front side lamp
7 Centre High Mounted Stop Lamp (CHMSL)
8 Trailer module
9 Number plate lamps
10 Brake / Rear direction indicator lamp
11 Tail lamp / Tail and rear fog lamp
12 Automatic headlamp levelling ECU (bi-xenon
headlamps only)
13 Hazard warning lamps switch
14 Front fog lamp
15 Headlamp – dip beam (dip/main beam with bi-
xenon lamps)
16 Headlamp – main beam
LIGHTING
86-2-4 DESCRIPTION AND OPERATION
Exterior Lighting Control Diagram –
Sheet 1 of 2
A = Hardwired; B = K Bus; K = I Bus
M86 5849
A
B
1
2
3
4
5
7
8
9
10
6
11
13
12
15
16
17
18
20
19
22
21
25
26
14
24
23
K
LIGHTING
DESCRIPTION AND OPERATION 86-2-5
1 LH Bi-xenon control unit
2 RH bi-xenon control unit
3 Fuse 50A - Permanent battery supply
4 Fuse 50A - Permanent battery supply
5 Instrument pack
6 Automatic headlamp levelling ECU (only with
bi-xenon lamps)
7 Rear RH height sensor
8 Front RH height sensor
9 LH headlamp levelling motor (only with bi-
xenon lamps)
10 RH headlamp levelling motor (only with bi-
xenon lamps)
11 Anti-lock Brake System (ABS) ECU
12 Fuse 5A - Ignition position I (AUX) feed
13 Fuse 5A - Ignition position II (IGN) feed
14 Ignition switch
15 Electrochromic interior rear view mirror
16 RH direction indicator side repeater lamp
17 LH direction indicator side repeater lamp
18 Number plate lamps
19 RH dip beam headlamp
20 RH main beam headlamp
21 LH main beam headlamp
22 LH dip beam headlamp
23 Light Check Module (LCM)
24 LH front fog lamp
25 RH front fog lamp
26 LH column switch
LIGHTING
86-2-6 DESCRIPTION AND OPERATION
Exterior Lighting Control Diagram –
Sheet 2 of 2
A = Hardwired
M86 5876
A
16
23
22
21
19
20
1
5
6
7
8
9
10
11
12
14
13
15
18
17
2
3
4
24
LIGHTING
DESCRIPTION AND OPERATION 86-2-7
1 LH rear tail lamp
2 LH rear direction indicator lamp
3 RH rear direction indicator lamp
4 RH rear tail lamp
5 Light control switch
6 LH rear fog lamp
7 RH rear fog lamp
8 LH brake lamp
9 Centre High Mounted Stop Lamp (CHMSL)
10 RH brake lamp
11 Navigation ECU
12 Rear wiper motor and control module assembly
13 LH front direction indicator lamp
14 LH front side lamp
15 RH front side lamp
16 RH front direction indicator lamp
17 RH reverse lamp
18 LH reverse lamp
19 Trailer module
20 Light Check Module (LCM)
21 RH rear side marker lamp (NAS only)
22 LH rear side marker lamp (NAS only)
23 LH front side marker lamp (NAS only)
24 RH front side marker lamp (NAS only)
LIGHTING
86-2-8 DESCRIPTION AND OPERATION
Description
General
The exterior lighting is controlled by the Light Check Module (LCM). The LCM controls the following vehicle functions:
l Control and monitoring of exterior lamps including direction indicators and hazard warning functionality
l Illumination dimmer control of instrument pack and all interior switch illumination
l Communication and control and monitoring of trailer lighting via the trailer ECU
l Control of power supply to automatic headlamp levelling ECU (only with bi-xenon headlamps option)
l Monitoring and evaluation of check control inputs from other system ECU's and output of applicable messages
in the instrument pack message centre.
The LCM is connected to the I Bus and communicates with other vehicle systems via the instrument pack. The LCM
contains a microprocessor which performs the control, monitoring and evaluation functions.
Light Check Module (LCM)
The LCM is located on the RH 'A' post, behind the trim panel. The LCM is connected to the vehicle wiring harness
with three multiplugs.
The LCM receives two permanent battery power supplies via the passenger compartment fusebox and power feeds
from the ignition switch positions I (AUX) and II (IGN).
The lighting circuits are not protected by conventional fuses. The control circuitry within the LCM for each individual
circuit can detect and isolate a problem circuit.
A monitoring system within the LCM can determine a bulb failure and indicate this to the driver via the instrument pack
message centre. The following table shows the bulbs monitored by the LCM and their type and rating:
LIGHTING
DESCRIPTION AND OPERATION 86-2-9
Exterior Bulb Type/Rating Table
The bulbs are driven by MOSFETS within the LCM. The LCM provides a Pulse Width Modulation (PWM) output to
the front parking lamp and the tail lamp bulbs to protect the bulbs. The PWM output is rapidly switched on and off to
provide bulb emulation when a bulb fails.
Input Signals for Lamp Control
The LCM receives inputs from the following switches:
l Lighting switch for side lamps and headlamps
l Momentary push switches for front and rear fog lamps
l Steering column switch for direction indicators and main beam/headlamp flash
l Brake switch
l Momentary push switch for hazard warning.
The switches are supplied with a 10mA supply from the LCM and switch to ground when operated. The LCM detects
that a switch has been operated (ON) when its closing resistance is less than 100Ω and is detected as OFF when its
resistance is more than 10KΩ.
The LCM also receives ignition switch status via hardwired connections and also on the I and K Bus via the instrument
pack.
A reverse gear engaged signal is also received on the I and K bus systems to enable the LCM to activate the reverse
lamps. The trailer module also outputs a signal to inform the LCM that a trailer is or is not connected. If a trailer is
connected, the LCM transfers control of the trailer reverse lamps and the rear fog lamp to the trailer module.
Via the bus systems the LCM receives a hazard warning lamp activation message from the DCU, via the BCU, in the
event of a crash or from the BCU if the alarm system is triggered.
Bulb Type Rating
Halogen headlamps – Dip beam Halogen H7U 55W
Bi-xenon headlamps – Dip beam Xenon DS2 35W
Headlamps – Main beam Halogen H7U 55W
Front fog lamps Halogen H7U 55W
Rear fog lamps Bayonet 21W
Direction indicators – front Bayonet 21W
Direction indicators – side repeater Capless 5W
Direction indicators – rear Bayonet 21W
Side lamps – front Bayonet 5W
Tail lamps Bayonet (Twin filament) 21W/5W
Brake lamps 19 LED's –
Centre High Mounted Stop Lamp
(CHMSL)
20 LED's –
Number plate lamps Festoon 5W
Reverse Lamps Bayonet 6W
Front side marker lamp (NAS only) Capless 5W
Rear side marker lamp (NAS only) Capless 5W
LIGHTING
86-2-10 DESCRIPTION AND OPERATION
LCM Harness Connector C0937 Pin Details
LCM Harness Connector C2039 Pin Details
LCM Harness Connector C2040 Pin Details
Pin No. Description Input/Output
1 Trailer module brake/right turn (NAS only) Output
2 LH tail lamp Output
3 Front RH side lamp Output
4 Front RH fog lamp Output
5 Rear LH number plate lamp Output
6 Front RH direction indicator lamp Output
7Ground –
8 Rear LH direction indicator lamp Output
9 Rear RH fog guard lamp Output
10 Brake lamps Output
11 LH main beam Output
12 Rear RH number plate lamp Output
13 RH dipped beam Output
14 RH side repeater lamp Output
15 Battery power supply Input
Pin No. Description Input/Output
1 Interior illumination Output
2Ground –
3 RH main beam Output
4 Front LH side repeater lamp Output
5 Front and rear LH side markers (NAS only) Output
6 LH dipped beam Output
7 Front LH fog lamp Output
8 Battery power supply Input
9 LH and RH reverse lamps Output
10 Bi-xenon control units Output
11 Front LH direction indicator lamp Output
12 Rear RH direction indicator lamp Output
13 Front and rear RH side markers (NAS only) Output
14 Rear LH fog guard lamp Output
15 Trailer module brake/left turn (NAS only) Output
Pin No. Description Input/Output
1 Lighting switch illumination Output
2 to 6 Not used –
7 Hazard warning switch on selection Input
8 Front fog lamp switch Input
9 Not used –
10 Washer fluid level sensor Input
11 and 12 Not used –
13 Auxiliary power supply Input
14 and 15 Not used –
16 Illumination dimmer switch Input
17 RH tail lamp Output
LIGHTING
DESCRIPTION AND OPERATION 86-2-11
Circuit Protection
Operation of the lamps is performed using overload proof Metal Oxide Semiconductor Field Effect Transistors
(MOSFETs). The MOSFETs have a diagnostic output for bulb monitoring and can detect overload, load interruption
with the lamps switched on and short circuit to positive with the lamps switched off.
The MOSFETs are protected against short circuits, removing the requirement for the lamps circuits to be protected
by fuses. The MOSFETs respond to heat generated by increased current flow caused by a short circuit. Normally this
would cause the fuse to blow. The MOSFETs react to the heat increase and cut the supply to the affected circuit. Once
the fault has been rectified or the MOSFET has cooled, the MOSFET will automatically reset and operate the circuit
normally.
If an overload occurs, the current flow is dependant on the temperature of the related MOSFET and can be up to 20
times the rated current of the lamp. The MOSFET heats up and deactivates the load applied to the circuit. When the
MOSFET cools the circuit is once again reactivated. This thermal cycling occurs continuously in the event of an
overload occurring.
The brake switch is also monitored by the LCM. If the LCM detects a short circuit to ground in the switch circuit it
activates messages to the driver in the message centre. These messages will display switch defective and LH and
RH stop lamp defective. The brake switch is also monitored when the ignition is in position II. The LCM checks the
acceleration speed of the vehicle (via bus messages). If the vehicle is accelerating and the brake switch is still active
after 10 seconds, the LCM starts a timer. If, after 2 minutes, the brake switch is still active and the vehicle is moving,
the LCM activates defective switch messages in the instrument pack message centre.
18 Front LH side lamp Output
19 Hazard warning switch lamp Output
20 to 23 Not used –
24 Engine coolant level sensor Input
25 Brake switch Input
26 Reverse gear selected Output
27 Headlamp levelling vertical aim control Output
28 Reverse gear selected Output
29 Illumination dimmer switch supply Output
30 Steering column lighting switch (left and right turn
selections)
Input
31 Ignition power supply Input
32 Not used –
33 Lighting switch headlamp selection Input
34 Not used –
35 Trailer module serial interface Input/Output
36 I bus Input/Output
37 and 38 Not used –
39 Reverse gear selected Output
40 Not used –
41 Brake fluid level switch Input
42 to 44 Not used –
45 Rear fog guard lamp switch Input
46 Not used –
47 HDC active signal Input
48 and 49 Not used –
50 Steering column lighting switch, main/dipped beam and
flash selection
Input
51 Lighting switch side lamp selection Input
52 Lighting switch ground –
53 and 54 Not used –
Pin No. Description Input/Output
LIGHTING
86-2-12 DESCRIPTION AND OPERATION
Bulb Monitoring
Bulb failure monitoring is performed by the LCM processor. The lamps are cold and warm monitored by the MOSFETs
in order to detect bulb failure.
The LCM processor outputs to each MOSFET. This output switches the MOSFET to supply the required output to
power the lamp circuit. The microprocessor evaluates the lamp circuits by detecting the returned signals from the
controlling MOSFET.
When the bulb is functioning normally, the output signal voltage from the controlling MOSFET is 0V. If a bulb in the
circuit fails, an open circuit occurs and the MOSFET outputs a signal of 5V to the processor. The signal is interpreted
as a bulb failure and generates a message which is output on the I Bus to the instrument pack. The instrument pack
displays the applicable bulb failure message in the message centre to provide visual warning to the driver.
Warm monitoring is performed continuously when the lamps are switched on by evaluating the diagnostic output of
the MOSFET switches. Cold monitoring is performed at 32 second intervals when the lamps are switched off. The
MOSFETs briefly switch on the lamps for approximately 1 millisecond (this is insufficient to illuminate the bulb) and
checks the bulb as per warm monitoring.
Cold monitoring is not possible for the dip beam headlamps of vehicles using xenon bulbs. On these vehicles the cold
monitoring of the dip beam headlamps is switched off in the LCM. The LCM detects a failed xenon bulb via a reduction
in current flow to the affected headlamp's xenon control module.
When a xenon bulb fails, the control module's current consumption falls to 60mA, which the LCM detects as
unsuccessful bulb illumination. The xenon control modules have a diagnostic capability and can store fault related
codes.
Alarm Indications
The LCM communicates on the I and K Buses with the BCU to display alarm visual indications for alarm arm, disarm
and triggered conditions.
+ SECURITY, DESCRIPTION AND OPERATION, Description.
If the hazard warning lamps are active when a lock or unlock request is made, the hazard warning cycle is interrupted
to allow the visual indication of the requested lock cycle. When visual indication is completed, the hazard warning
operation will continue.
If the vehicle is involved in crash of a severity for the DCU to initiate deployment of the airbags, the DCU outputs a
hazard warning lamps on request on the K bus to the instrument pack and on the I bus from the instrument pack to
the LCM. The hazard warning lamps will be activated and will continue until the DCU outputs a message to deactivate
the hazard warning lamps or until the hazard warning lamp switch is pressed.
Redundant Data Storage
The LCM stores data relating to the Vehicle Identification Number (VIN), total mileage and service interval indicator.
This data is received by the LCM from the instrument pack and used as a back-up in the event of instrument pack
replacement.
If the LCM is to be replaced, TestBook/T4 must be connected to the vehicle and the replace LCM procedure followed
to ensure that the stored data is transferred to the new unit.
+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
Low Voltage Operation
If the battery voltage falls below 11.2V, the LCM operates the minimum lighting to preserve the remaining battery
charge.
LIGHTING
DESCRIPTION AND OPERATION 86-2-13
Lighting Control Switch
1 Light control rotary switch
2 Off position
3 Side lamps position
4 Headlamps position
5 Instrument illumination dimmer rheostat
6 Rear fog lamp switch
7 Front fog lamp switch
The light control switch is located in the fascia between the steering column and the driver's door. The switch
comprises a three position rotary switch for controlling side lamps and headlamps, a thumbwheel rheostat which
manually controls the fascia and interior switch night illumination, and momentary push switches for front and rear fog
lamps.
The rotary side and headlamp control switch has three connections to the LCM. One connection supplies a reference
voltage to the switch contacts. The two remaining connections supply a combination of earth paths to the LCM for the
side lamp or headlamp selection contacts.
The front and rear fog lamp switches operate in a similar way, completing earth paths to the LCM when the switch is
pressed. The fog lamp switches are momentary, non-latching switches which briefly complete an earth path which is
sensed by the LCM.
LIGHTING
86-2-14 DESCRIPTION AND OPERATION
Headlamp Assembly
Two headlamps systems are available; Halogen or bi-xenon. The two types of headlamps share a common lens. NAS
vehicles use a different lens to other markets but these are also common between the NAS specification halogen and
bi-xenon lamps.
Halogen Headlamps
1 Lens retaining clips
2 Bolts – headlamp assembly to front panel
3 Halogen bulb 55W – main beam
4 Main beam bulb access cover
5 Halogen bulb 55W – dip beam
6 Dip beam bulb access cover
7 Bolts – headlamp mounting bracket
8 Screw
9 Headlamp mounting bracket
10 Lens
11 Gasket
12 Headlamp assembly
LIGHTING
DESCRIPTION AND OPERATION 86-2-15
The halogen headlamps use a complex surface reflector for both the dip and main beam lighting units. This type of
reflector is divided into separate parabolic segments, with each segment having a different focal length. The reflector
segments differ between the dip and main beam lamps to produce the correct beam 'throw' for each lamp.
Both the dip and main beam bulbs are quartz halogen, with a rating of 55W. The bulbs are retained in the headlamp
unit with conventional wire retaining clips.
Bi-xenon Headlamps
1 Lens retaining clip
2 Bolt – headlamp assembly to front panel
3 Halogen bulb 55W – main beam
4 Main beam bulb access cover
5 Xenon bulb – dip/main beam
6 Xenon bulb access cover
7 Xenon control unit
8 Bolts – headlamp mounting bracket
9 Screw
10 Headlamp mounting bracket
11 Lens
12 Gasket
13 Headlamp assembly
LIGHTING
86-2-16 DESCRIPTION AND OPERATION
The Bi-xenon headlamps use a complex surface reflector for the halogen fill in main beam only lighting unit, as used
on the halogen headlamp. This type of reflector is divided into separate parabolic segments, with each segment
having a different focal length.
The main beam bulbs are quartz halogen, with a rating of 55W. The bulbs are retained in the headlamp unit with
conventional wire retaining clips.
The bi-xenon headlamps operate as a dip beam and a main beam headlamp unit. The xenon lamp comprises a
projector lens with a solenoid controlled shutter to change the beam output from dip to main beam.
NOTE: Bi-xenon lamps do not operate when the main beam 'flash' function is operated.
The bi-xenon headlamp system is controlled by the LCM using a control module and igniter located on each headlamp
to operate the xenon bulb. The control modules and igniters provide the regulated power supply required to illuminate
the xenon bulbs through their start-up phases of operation.
Safety Precautions
WARNING: The xenon system generates up to 28000 volts and contact with this voltage could lead to fatality.
Make sure the headlamps are switched off before working on the system.
The following safety precautions must be followed when working on the xenon headlamp system:
l DO NOT attempt any procedures on the xenon headlamps when the lights are switched on
l Handling of the DS2 xenon bulb must be performed using suitable protective equipment, e.g. gloves and goggles.
The glass part of the bulb must not be touched
l Xenon bulbs must disposed of as hazardous waste
l Only operate the lamp in a mounted condition in the reflector.
Bi-xenon / Halogen Beam Comparison
50m
100m
M86 5854
XENON
50m
100m
HALOGEN
LIGHTING
DESCRIPTION AND OPERATION 86-2-17
The bi-xenon dip/main beam headlamps use ellipsoidal technology for the lens and reflector providing improved night
time visibility compared with conventional halogen headlamps. The bi-xenon headlamps provide the following benefits
when compared to halogen headlamps:
l Longer bulb life – Approximately 3 to 5 times longer than a halogen bulb
l Increased light output – Xenon headlamps output 2.5 to 3 times more lumens than halogen headlamps (lumens
is a measure of light energy emitted per second on a given area over a given distance)
l Blue/white light which simulates natural daylight – Xenon bulbs produce a blue/white light compared to the yellow
light produced by a halogen bulb.
l Improved night time driving visibility – Xenon lamps produce a wider and brighter beam in front of the vehicle
than conventional halogen bulbs.
l Lower operating temperatures
l Lower power consumption.
LIGHTING
86-2-18 DESCRIPTION AND OPERATION
Xenon Headlamp Construction
1 Reflector
2 Shutter controller
3 Shutter
4 Adapter ring
5 Spring clip
6 Lens
7 Foreign touring beam adjustment lever
8 Xenon bulb
9 Bulb retention ring
43
2
M86 5875
5
45,88
1
6
7
8
9
LIGHTING
DESCRIPTION AND OPERATION 86-2-19
The xenon headlamp unit is a self contained unit located within the headlamp assembly. The unit comprises a
reflector, an adaptor ring, the lens, a shutter controller and the xenon bulb.
The lens is curved and provides the mounting for the xenon bulb. The bulb locates in two recesses to ensure correct
alignment in the reflector and is secured with a retention ring. The retention ring locates over the bulb and is turned
clockwise to lock the bulb in the holder. The bulb has a two pin connector which is also a push and turn to lock fitting.
The adapter ring is attached to the reflector and provides for the attachment of the lens. The lens is attached to the
adapter ring with an internal spring clip.
The shutter controller is a solenoid which operates, via a lever mechanism, the shutter. The shutter is used to change
the beam projection from dip beam to main beam and visa versa.
A beam adjustment mechanism is located between the reflector and the adapter ring. This mechanism rotates to blank
off a portion of the beam spread to enable the vehicle to be driven in opposite drive hand markets without applying
blanking decals to the headlamp lens. The beam is changed by removing the access cover at the rear of the lamp
assembly and moving a small lever located near the bulb holder, at the side of the reflector.
Crash Signal Activation
In the event of an accident of a severity to activate and deploy the airbags, the DCU requests various electrical
operations to assist with the crash situation. The DCU requests via the bus systems to the LCM to activate the hazard
warning lamps.
Security System Activation
In the event of the security system being triggered, the BCU requests activation of the hazard warning lamps. In some
markets the low beam and/or high beam headlamps can also be activated.
Headlamp Levelling (Xenon headlamps only)
The automatic headlamp levelling system automatically adjusts the vertical positioning of the headlamps to provide
the optimum headlamp beam position for maximum driving visibility and preventing glare to oncoming drivers.
The system is controlled by an automatic headlamp levelling ECU located at the bottom of the LH 'A' post. The ECU
is connected to and receives information from the Hall effect front and rear height sensors which are also used by the
air suspension system. The ECU also receives a signal from the ABS ECU for vehicle acceleration. The ECU has
diagnostic capabilities and can communicate with TestBook/T4 via the K Bus, the instrument pack and the DS2 Bus.
The levelling system is a fast response system which reacts to changes of vehicle angle when driving. The ECU
receives vehicle speed signals from the ABS ECU and a brake switch signal from the LCM. These two signals are
used to adjust the headlamp position to compensate for changes in vehicle attitude due to acceleration or braking.
Stepper motors, located as part of the headlamp unit, drive a threaded rod which moves the lower edge of the
headlamp forward or backwards to adjust the vertical position of the headlamp beam. The stepper motors are
controlled by the ECU which, using the data from the height sensors, determines the attitude of the vehicle and
compensates for load differences at the rear of the vehicle or changing driving conditions.
LIGHTING
86-2-20 DESCRIPTION AND OPERATION
Front Side and Direction Indicator Lamp Assembly
1 Front side and direction indicator lamp
assembly
2 Direction indicator bulb
3 Direction indicator bulb holder
4 Side lamp bulb holder
5 Side lamp bulb
6 Side marker lamp bulb holder (NAS only)
7 Side marker lamp bulb (NAS only)
The front side and direction indicator lamp assemblies are located outboard of each headlamp assembly. The
direction indicator bulbs are 21W bayonet fitting and the side lamp bulbs are 5W bayonet fittings.
The lamp assembly is retained by two integral plastic clips which locate in the headlamp assembly housing. A
threaded shaft locates in a hole in the adjacent wing panel. A knurled nut is and washer is fitted to the threaded shaft
and positively retains the lamp assembly in position. The knurled nut allows for the lamp assembly to be in or out
providing adjustment to ensure flush alignment with the wing contour.
The direction indicator and side lamp bulbs are located in holders. The holders are secured in the lamp housing by
rotating through 90°. Each holder has a connector to allow for connection to the electrical harness.
On NAS vehicles, an additional lamp holder is used to accommodate the side marker lamp. The lamp assembly lens
has a vertical section which is used as the side marker illumination required for the NAS market. The side marker lamp
bulb is a 5W bayonet fitting.
LIGHTING
DESCRIPTION AND OPERATION 86-2-21
Front Fog Lamps
1 Lamp assembly
2 Halogen bulb
3 Bulb holder
The front fog lamps are located in the front bumper. Each lamp is secured to three lugs in the bumper and retained
with self tapping screws and fasteners. Each lamp has two adjusting screws which provide for the vertical and
horizontal alignment of the beam.
The 55W halogen bulb is located in a holder. The holders are secured in the lamp housing by rotating through
approximately 10°. The holder has a connector to allow for connection to the electrical harness.
LIGHTING
86-2-22 DESCRIPTION AND OPERATION
Rear Side and Direction Indicator Lamp Assembly
1 Rear lamp holder
2 Direction indicator bulb
3 Direction indicator reflector
4 Brake lamp LED assembly
5 Tail lamp lens
6 Side marker lamp bulb (NAS only)
7 Side marker lamp bulb holder (NAS only)
8 Bulb – tail lamp twin filament
9 Bulb – tail/rear fog lamp
The rear side and direction indicator lamp assemblies are located on the outer corner of each rear wing panel.
The lamp assembly is retained by two integral plastic clips which locate in corresponding clips secured to the body
panel. The assembly is further retained by two self tapping screws which are accessed from inside the taildoor
aperture. To remove the assembly, after removing the screws, the assembly must be prised at two indentations to
release the clips. A non-metallic tool must be used with care to avoid damage to the paint finish.
The direction indicator, fog lamp and side lamp bulbs are located in a holder. The holders is secured in the lamp
housing by two plastic clips. The holder has a connector to allow for connection to the electrical harness.
The upper lamp aperture is for the brake lamp and the direction indicator. The brake lamp comprises a plastic holder
with contains 19 LED's. This illuminates through a circular prism lens in the centre of the lamp to display the brake
lamp in a red colour. The direction indicator lamp is located behind the brake lamp LED unit. The bulb is located in a
reflector unit which emits the direction indicator light around the outer diameter of the brake lamp LED assembly.
The lower lamp aperture is divided into two parts and provides for the tail lamp and the rear fog lamp The rear fog
lamp uses a 21W bulb in the lower half of the aperture. This is also used for the tail lamp, operated by a PWM output
from the LCM to produce a lower wattage output than the fog lamp. The upper half of the tail lamp aperture is used
solely for the tail lamp and uses a 21W/5W bulb. Only the 5W filament is used for the tail lamp, with the 21W filament
not used by any function.
LIGHTING
DESCRIPTION AND OPERATION 86-2-23
Side Repeater Lamps
1 Lens
2 Lamp body
3 Bulb
4 Bulb holder
The side repeater lamps are located in the front wings, forward of the louvred air vents. The side repeater lamps are
clipped into the wing aperture and can be removed by pushing forwards and pulling outwards from the wing.
The side repeater lamps use a capless 5W bulb which is pressed into contacts in a holder. The holder is located in
the lamp assembly
Hazard Warning Lamps
The hazard warning lamps use the front and rear direction indicator lamps as previously described. These are
controlled by the LCM in response to a hazard warning lamp request from the fascia switch.
Crash Signal Activation
In the event of an accident of a severity to activate and deploy the airbags, the DCU requests various electrical
operations to assist with the crash situation. The DCU requests via the bus systems to the LCM to activate the hazard
warning lamps. These will continue to operate until deselected using the fascia switch. The lamps flash at a frequency
which is the same as the frequency used to flash the headlamp main beam in the same situation.
Reverse Lamps
The reverse lamps are located in the lower tail door and position at either side of the number plate. The lamps are
secured in the tail door with a clip at the bottom and positively secured with a screw at the top.
Each reverse lamp uses a 6W bayonet type bulb. The LCM monitors the bulbs and, if a failure is detected, alerts the
driver via the instrument pack message centre.
Number Plate Lamps
Two number plate lamps are located in the trim above the number plate in the lower tail door. The lamps are press
fitted in their apertures and secured by an integral plastic clip.
Each lamp uses a 5W festoon type bulb. The LCM monitors the bulbs and, if a failure is detected, alerts the driver via
the instrument pack message centre.
LIGHTING
86-2-24 DESCRIPTION AND OPERATION
Daylight Running Lamps (selected markets only)
In markets which require daylight running lamps, the LCM is programmed with coding which activates the dip beam
or dimmed main beam headlamps when the ignition is in position II.
Daylight running lamps can only be switched on or off using TestBook providing the LCM is not coded with a country
specific code.
Canadian market vehicles use the main beam headlamps with a dimmed output of 5.5 to 6.0V, controlled by the LCM.
Also, on Canadian vehicles with bi-xenon lamps, only the halogen main beam lamp is illuminated using a reduced
voltage of 5.5 to 6.0V. All other countries using daylight running lamps (Finland, Norway and Sweden) use the full
power dip beam headlamps.
Main Beam/Direction Indicator Column Control Switch
1 RH direction indicator
2 Headlamp flash
3 LH direction indicator
4 Headlamp main beam
The main beam/direction indicator column control switch is located on the left hand side of the steering column and
controls the following functions:
l Headlamp dip/main beam
l Headlamp main beam flash
l Left/right direction indicators
l Trip computer functions.
+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
The main beam on and flash functions are connected on a single wire to the LCM. The switch assembly contains
resistors and the ground for each selection is passed through a different resistor for each selection. The same also
applies to the direction indicators. The LCM senses the resistance on the ground wire and determines which function
has been selected.
M86 5859
1
2
3
4
LIGHTING
DESCRIPTION AND OPERATION 86-2-25
Trailer Module
The trailer module is fitted to all vehicles and is located in the RH side of the luggage compartment, behind the
removable trim panel, adjacent to the rear fusebox. The module is required to separate the load circuits of the trailer
from the load circuits of the towing vehicle. This allows separate monitoring of the vehicle lamps and the trailer circuits.
The trailer module comprises a double transistor for reverse lamp and rear fog lamp operation and overload proof
MOSFET circuit breakers for the following lamps:
l Left direction indicator
l Right direction indicator
l Brake lamps
l Left tail lamp
l Right tail lamp
l Permanent trailer battery supply circuits.
The above lamps are connected to the trailer module via direct connections to the applicable lamps. The rear fog
lamps and reverse lamps are not directly connected to the lamps units because these lamps must be disabled when
the trailer socket is connected.
The LCM communicates with the trailer module via a bi-directional, dedicated serial link. The rear fog lamps and
reverse lamps are controlled on this link. The trailer module also uses this link to transmit error messages for the trailer
lamps to the LCM.
The trailer module has two modes of operation; sleep mode and normal mode. Sleep mode is initiated by the LCM
after a predetermined time. In this mode the trailer module processor clock speed is reduced to a minimum and all
loads are switched off to keep current consumption to a minimum. The module operates in normal mode on receipt
of an applicable message from the LCM. The required loads and the current supply for bulb failure detection are
activated.
The LCM communicates with the trailer module every 2 seconds with a normal mode telegram. If the trailer module
no longer responds, the data link to the module is switched low for 1 second after ten unsuccessful attempts to
establish the communication. When the LCM switches the data link low, the trailer module is 'reset'. If communication
is not established after thirty attempts in succession, the LCM assumes the module is defective and records an
applicable error message in the error memory.
If a replacement trailer module is fitted, the LCM instantly recognises it via the data link. Connection of TestBook/T4
is not required to establish communications between the LCM and the trailer module.
Trailer module Harness Connector C0380 Pin Details
Pin No. Description Input/Output
1Brake lamps Output
2 Reverse lamps Output
3 Rear fog guard lamps Output
4 LH tail lamp Output
5 RH direction indicator lamp Output
6 RH tail lamp Output
7 LH direction indicator lamp Output
8 Battery power supply Input
9 Brake lamps Input
10 RH direction indicator lamp Input
11 LH tail lamp Input
12 LH direction indicator lamp Output
13 Serial interface with LCM Input/Output
14 RH tail lamp Output
15 Ground –
LIGHTING
86-2-26 DESCRIPTION AND OPERATION
Instrument Panel and Switch Illumination Dimming
The LCM controls the instrument pack backlighting illumination and also illumination of all switches.
The LCM supplies a power output to all switch illumination bulbs at a voltage determined by the position of the manual
dimmer rheostat. The switch illumination is activated when the light control switch is in the side lamp or headlamp
position.
Diagnostics
1 Cover 2 Diagnostic socket
The diagnostic socket allows for the transfer of information between the LCM, the automatic headlamp levelling ECU
and TestBook/T4. The diagnostic socket is located in the fascia, in the driver's stowage tray. The socket is secured
in the fascia and protected by a hinged cover.
The LCM has diagnostic capabilities and store fault codes relating to the lighting systems. The xenon control modules
cannot be interrogated via the LCM, but the LCM incorporates xenon specific diagnosis up to the control modules.
The xenon control modules, located on the rear of the headlamp assemblies, can be interrogated using TestBook/T4
for faults relating to the operation of the xenon lamps. The control modules are connected on a DS2 link to the
diagnostic socket.
LIGHTING
DESCRIPTION AND OPERATION 86-2-27
Operation
General
The following section describe the functionality of the individual light circuits. The control of the circuits is performed
by coding data in the LCM EEPROM. This coding is programmed on the production line and some coding for lamp
functionality is country specific.
Direction Indicator and Hazard Warning Lamps
With the ignition switch in position I or II, the direction indicators can be operated. When the column switch is moved
to the left or right direction position the direction indicator lamps are activated with a pulse rate of 640 milliseconds
and a pulse duty factor of 50:50. If the operation is in the illuminated phase and the direction indicator is switched off,
the flashing phase will end. If the switch position is rapidly moved to from the left position to the right position (or visa
versa), the applicable direction indicator lamps are switched over immediately.
If one of the vehicle or trailer direction indicator bulbs, with the exception of the side repeater lamps, is defective, the
flashing frequency is doubled.
If the ignition is in position I or II and a left or right direction indicator is active, depressing the hazard warning switch
will operate the hazard warning lamps, overriding the direction indicator function. when the hazard warning lamp
switch is pressed a second time, the hazard warning lamp function is deactivated and the direction indicator operation
reinstated, if still selected on.
If the ignition is in position I or II and the hazard warning lamps are active, operating the column switch for the left or
right direction indicators will suspend the hazard warning lamp operation and activate the selected direction indicator.
When the direction indicator column switch is moved to the off position, the hazard warning function will be reinstated.
If the hazard warning lamps have been activated by an I and K Bus message to the LCM in response to a crash
detection, the hazard warning lamps can be switched off using the hazard warning lamp switch. If the hazard warning
lamps have been activated by the BCU due to an anti-theft alarm trigger, the hazard warning lamps can only be
switched off by a deactivate message from the BCU. The hazard warning lamps will also deactivate after 5.5 minutes.
The direction indicator warning lamps and the direction indicator sound are controlled by the instrument pack. They
are activated by the instrument pack on receipt of a lamp status message from the LCM. The direction indicator
warning lamps and the sounder are synchronised with this message with the direction indicator lamp illumination
frequency.
Parking Lamps
The parking lamp function is controlled using the direction indicator column switch. If the ignition is off and the direction
indicator switch is moved to the left or right position, the selected parking lamps will be illuminated. The front parking
lamp is illuminated, along with the top bulb in the rear tail lamp. On NAS vehicles the applicable side marker lamps
are also illuminated. The number plate lamps and the lower bulb in the tail lamp for the selected side are deactivated.
No instrument pack or fascia illumination is activated. If the ignition is on and the direction indicator switch is in the
left or right position, the selected side lamps will not be activated when the ignition is subsequently switched off.
Side Lamps
If the light control switch is in the side lamp or headlamp position, the front side lamps and rear tail lamps are activated.
Both the upper and lower tail lamp bulbs are active along with the number plate lamps. On NAS vehicles, the side
marker lamps are also active.
The instrument pack and fascia illumination remains illuminated at the brightness determined by the position of the
dimmer control.
Light Control Switch Illumination
When the ignition is in position I or II, the switch legends on the light control switch are illuminated at maximum
brightness when the light control switch is in the 'O' (off) position. when the light control switch is rotated to the side
or headlamp position the legend illumination is dimmed.
LIGHTING
86-2-28 DESCRIPTION AND OPERATION
Low Beam Headlamps
The low beam headlamps are activated when the light control switch is in the headlamp position and the ignition is in
position II.
High Beam Headlamps
The main beam headlamps are activated when the light control switch is in the headlamp position and the ignition is
in position I or II. Moving the column switch forwards from the low beam position activates the main beam headlamps.
When the ignition is in position I or II and the column switch is moved rearwards to the headlamp flash position, the
main beam lamps are activated for as long as the switch is held in this position.
If the vehicle is involved in an accident and the airbags are deployed, the crash message from the DCU also
illuminates the main beam headlamps which flash at the same frequency as the hazard warning lamps.
The functionality of the main beam differs between halogen only and bi-xenon and halogen headlamps. This is shown
in the following table:
Xenon Headlamps
The xenon bulbs illuminate when an arc of electrical current is established between two electrodes within the bulb.
The xenon gas sealed in the bulb reacts to the electrical excitation and the heat generated by the current flow. The
Xenon gas reacting to the controlled current flow between the electrodes produces the blue/white light.
To operate at full efficiency, the xenon bulb go through three phases of operation before full output for continuous
operation is achieved. The three phases are; starting phase, warm-up phase and continuous phase.
WARNING: The xenon system generates up to 28000 volts and contact with this voltage could lead to fatality.
Make sure the headlamps are switched off before working on the system.
In the start-up phase the bulb requires an initial high voltage starting pulse of 18000 to 28000 volts to establish the
arc. This is produced by the igniters. The warm-up phase begins once the arc is established. The control modules
regulate the supply to the bulbs to 2.6A which gives a lamp output of 75W. During this phase, the xenon gas begins
to illuminate brightly and the environment within the bulb stabilises ensuring a continual current flow between the
electrodes. When the warm-up phase is complete, the control modules change to continuous phase. The supply
voltage to the bulb is reduced and the operating power required for continual operation is reduced to 35W.
The xenon system is controlled by the LCM, two control modules and two igniters. The control modules (one per
headlamp) receive an operating voltage from the LCM when the headlamps are switched on. The control modules
regulate the power supply required through the phases of start-up. The control modules also have diagnostic
capability which can be accessed using TestBook/T4 via the diagnostic socket.
The igniters (one per headlamp) generate the initial high voltage required to establish the arc. The igniters have
integral coils which generate high voltage pulses required for start-up. Once the xenon bulbs are operating, the igniter
provide a closed circuit for regulated power supply from the control modules
Front Fog Lamps
The front fog lamps are only active with the ignition switch in position II and the light control switch in the side lamp or
headlamp position. When the ignition is switched off, the fog lamp selection is automatically deselected.
Light Control Switch Position Halogen Main Beam Only Bi-xenon and Halogen Main Beam
0 OFF OFF OFF
0 + flash ON OFF ON
I OFF OFF OFF
I = flash ON OFF ON
II OFF OFF OFF
II + flash ON OFF ON
II + main ON ON ON
Daylight running lamps (Canada only) ON (5.5 to 6.0V) OFF ON (5.5 to 6.0V)
LIGHTING
DESCRIPTION AND OPERATION 86-2-29
Rear Fog Lamps
The rear fog lamps are only active with the ignition switch in position II. With the light control switch in the side lamp
position, the rear fog lamps can only be selected on when the front fog lamps are active. If the front fog lamps are
subsequently switched off, the rear fog lamps are automatically deselected.
With the light control switch in the headlamp position, the rear fog lamps can be activated individually, irrespective of
the front fog lamp status.
Brake Lamps
The brake lamps are active with the ignition switch in positions I or II. The LCM receives an input from the brake switch
which is used as a signal to activate the brake lamps. When HDC is active, the ABS ECU outputs a signal on a
separate hardwired connection to the LCM to activate the brake lamps when the HDC function is operating.
Reverse Lamps
The reverse lamps will operate with the ignition switch in position II. The LCM activate the reverse lamps on receipt
of an message on the I Bus that reverse gear has been engaged.
Main Beam/Direction Indicator Column Control Switch
Moving the switch rearwards, towards the driver, completes a ground path to the LCM. The ground path is completed
through a 1.2kΩ resistor which is sensed by the LCM. On receipt of this signal, the LCM activates the main beam
headlamps for as long as the switch is operated. This position is non-latching and operates with the ignition switch in
position I, but without the side lamps or headlamps being switched on.
Moving the switch forwards, into a latching position, completes a ground path to the LCM. The ground path is
completed through a 300Ω resistor which is sensed by the LCM. On receipt of this signal, the LCM activates the main
beam headlamps. The main beam will remain active until the switch is moved rearwards again, removing the ground
path. This function only operates when headlamps are selected on with the light control switch and the ignition switch
is in position II.
Moving the switch upwards or downwards completes a ground path to the LCM. The ground path is completed
through a 1.2kΩ resistor for the RH direction indicator or through a 300Ω resistor for the LH direction indicators which
is sensed by the LCM. On receipt of this signal the LCM activates the RH or LH direction indicators. The switch is a
latching switch, although the direction indicators can also be operated by lightly pushing the switch without engaging
the latch. The direction indicators will remain active until the switch is moved to the central off position. The direction
indicators operate with the ignition switch in position I.
With the ignition switched off, this switch position also operates the selected side parking lamps. Refer to 'Parking
Lamps' operation earlier in this section for details.
Automatic Headlamp Levelling (Xenon headlamps only)
The automatic headlamp levelling is only used on vehicle fitted with xenon headlamps. When the LCM detects that
the ignition is in position II and the side lamps or headlamps have been selected on using the light control switch, the
headlamp levelling control is activated. The headlamp levelling control is also activated when the LCM receives an
'engine running' signal on the I Bus, irrespective of the light control switch position.
When initially activated, the automatic headlamp levelling ECU cycles the stepper motors through their full range of
adjustment and stops at a default position. The ECU monitors the air suspension height sensor signals to determine
the vehicle angle and adjusts the headlamps accordingly. As the vehicle is driven, the ECU continuously monitors the
signals from the front and rear RH level sensors and also uses the speed and brake signals to determine the
operation. The ECU filters rapid changes of signals from the height sensors to prevent unnecessary adjustment.
LIGHTING
86-2-30 DESCRIPTION AND OPERATION
Headlamp Delay
The LCM controls a headlamp delay function which illuminates the driveway after leaving the vehicle. The headlamp
delay will operate on dipped beam headlamps only regardless of the position of the column stalk switch.
The delay is operated when the ignition is switched off and the key removed with the headlamps switched on. The
message centre displays a 'HEADLIGHTS ON' message accompanied by a chime from the sounder. When the light
control switch is moved to the 'off' position, the message centre displays a 'HEADLIGHT DELAY' message and the
dip beam headlamps are activated for a period of approximately 45 seconds. After the delay period, the LCM
automatically switches off the delay function, extinguishing the headlamps.
Instrument Pack Warning Lamp Illumination
The warning lamps in the instrument pack for left and right direction indicator, front and rear fog lamps and headlamp
main beam are activated by the LCM via messages to the instrument pack on the I Bus. The synchronisation of the
indicator warning lamps with the external lamp frequency is controlled by a cyclic transmission of the light status on
the I Bus.
LIGHTING
DESCRIPTION AND OPERATION 86-2-31
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DESCRIPTION AND OPERATION
LIGHTING
86-2-32 DESCRIPTION AND OPERATION
Interior Lighting Component Location
M86 5863
9
8
1
4
11
5
6
7
12
12
13
14
15
16
17
2
3
8
10
9
LIGHTING
DESCRIPTION AND OPERATION 86-2-33
1 Light Check Module (LCM)
2 LH vanity mirror illumination lamps
3 RH vanity mirror illumination lamps
4 Front map reading lamp (2 off)
5 Front interior lamp
6 Rear map reading lamp (2 off)
7 Rear interior lamp
8 Door handle illumination LED (4 off - 1 per door)
9 Door pocket illumination (6 off - 2 per front door
and 1 per rear door)
10 Door mirror approach lamps
11 Luggage compartment lamp
12 Upper tail door lamps
13 Rear door puddle lamps
14 Front door puddle lamps
15 Footwell lamps (2 off)
16 Sill lamps (2 off)
17 Glovebox lamp
LIGHTING
86-2-34 DESCRIPTION AND OPERATION
Interior Lighting Control Diagram
A = Hardwired
9
M86 5862
1
A
2
3
4
5
6
7
8
10
11
12
13
18
17
19
20
21
22
23
14
16
15
24
25
26
LIGHTING
DESCRIPTION AND OPERATION 86-2-35
1 Fuse – Permanent battery supply (5A)
2 Fuse – Ignition supply (30A)
3 Front interior lamp assembly
4 Rear interior lamp assembly
5 Glove box lamp and switch
6 Sill lamp LH (fascia mounted)
7 Sill lamp RH (fascia mounted)
8 RH door mirror approach lamp
9 LH door mirror approach lamp
10 LH rear door puddle lamp
11 RH rear door puddle lamp
12 Passenger door puddle lamp
13 Driver's door puddle lamp
14 Fuse – vanity mirror illumination
15 RH vanity mirror illumination lamps
16 LH vanity mirror illumination lamps
17 LH footwell lamp (under fascia mounted)
18 RH footwell lamp (under fascia mounted)
19 LH upper tail door lamp
20 RH upper tail door lamp
21 Load space illumination lamp
22 Upper tail door latch motor switch
23 Body Control Unit (BCU)
24 Interior lamp relay
25 Fuse – Ignition switched supply (5A)
26 Ignition switch
LIGHTING
86-2-36 DESCRIPTION AND OPERATION
Description
General
The interior lighting is controlled by the Body Control Unit (BCU) which is located below the front passenger seat. The
interior lighting comprises the following lamps:
l Front interior lamp unit
l Rear interior lamp unit
l Upper tail door load space lamps (2 off)
l Luggage compartment load space lamp
l Fascia mounted sill lamps (2 off)
l Under fascia footwell lamps (2 off)
l Door mirror approach lamps (2 off)
l Puddle lamps (4 off).
The interior lamps have two modes of operation; automatic or manual. In the automatic mode the interior lamp
functionality is controlled by the BCU on receipt of various input signals. In manual mode, the lamps can be switched
on and off using the momentary button adjacent to the front interior lamp or can be disabled completely using the
same switch.
NOTE: The LED illumination of the front door pockets and the front and rear interior door handles is a function of the
LCM and only operates when the light control switch is in the side lamp or headlamp positions.
The following table shows the bulbs used for the interior lighting and their type and rating:
Front and Rear Interior Lamps and Map Reading Lamps
The front and rear interior lamp assemblies are similar in design. The front interior lamp switch is connected directly
to the BCU and controls the manual operation of the interior lamp functionality. The rear interior lamp switch is used
only to switch the lamp on and off.
The map reading lights have a non-adjustable beam and are controlled via separate switches. Both the interior and
map reading lamps use capless 5W bulbs.
Luggage Compartment Lamps
The luggage compartment lamps comprise one lamp unit located on the RH side trim panel, adjacent to the auxiliary
power socket, and two lamps located in the interior trim panel of the upper tail door. All of these lamps are of the same
design and use capless 5W bulbs. The lamps are controlled by the BCU and operate on the automatic interior lamp
functionality.
Glovebox Lamp
The glovebox lamp is located inside the glovebox, at the top, adjacent to the latch. The lamp comprises a festoon 5W
bulb. The lamp housing also incorporates a plunger type switch which is activated to switch the lamp on when the
glovebox lid is opened.
Bulb Type Rating
Front and rear interior lamps Capless 6W
Front and rear map reading lamps Capless 6W
Load space lamp Capless 5W
Luggage compartment lamps (upper tail door) Capless 5W
Vanity mirror lamps Festoon 14V 0.1A (0.14W)
Door puddle lamps Capless 5W
Fascia sill lamps Capless 3W
Lower fascia footwell lamps Capless 5W
Door mirror approach lamps Capless 6W
Glovebox lamp Festoon 5W
LIGHTING
DESCRIPTION AND OPERATION 86-2-37
Vanity Mirror Illumination Lamps
The vanity mirror lamps are located behind a hinged cover, either side of the mirror glass. A festoon type bulbs fitted
in contacts behind each lamp lens. The lamps are activated by a simple switch which operates when the mirror cover
is lifted.
Footwell Lamps
Two types of footwell lamps are fitted. Two directional sill lamps are located in the front of the fascia and illuminate
the sill area. These lamps use 3W capless bulbs.
Two further footwell lamps are located in the lower fascia closing panels and illuminate the area below the fascia.
These lamps use 5W capless bulbs. The lamps are controlled by the BCU and operate on the automatic interior lamp
functionality.
Door Puddle Lamps
Each of the doors is fitted with a puddle lamp to illuminate the ground below the door when the door is open. The front
door puddle lamps are located in the lower face of the door, facing the ground. The rear door puddle lamps are located
in the bottom of the door trim panel.
The puddle lamps use a capless 5W bulb. The puddle lamps are controlled by the BCU and operate on the automatic
interior lamp functionality.
Door Mirror Approach Lamps
The exterior mirror housings are fitted with a lamp which illuminates the area below the front door. The approach
lamps comprise a housing located inside the mirror and bulb holder with harness connector. The housing contains a
plastic lens which directs a beam of light in the required area. The approach lamps use a capless 6W bulb.
The lamps are controlled by the BCU, via a dedicated relay which is located at the rear of the passenger compartment
fusebox.
Diagnostics
Diagnostics for the interior lamps is limited to a check of the function of the front interior lamp switch. The BCU can
be interrogated using TestBook/T4 to establish the correct operation of the front interior lamp switch, the door
switches and the tail door switches.
+ BODY CONTROL UNIT, DESCRIPTION AND OPERATION, Description.
LIGHTING
86-2-38 DESCRIPTION AND OPERATION
Operation
General
The interior lamp operation is activated by any of the following inputs signals:
l Door switch contacts (front and rear)
l Ignition switch position I (Aux)
l Central locking, lock request
l Central locking remote handset operation
l Crash sensor
l Front interior lamp switch.
The load space lamp and the upper tail door lamps are not switched on with the interior lamps. These lamps are only
activated when the upper tail door is opened. When the upper tail door is opened, the interior lamps, in addition to the
load space lamps, are switched on and are subject to the BCU timers.
Automatic Operation
The automatic control of the interior lamps has several switch on and off conditions as follows:
l The interior lamps are switched on when one or more doors are opened. When all the doors are closed, the
interior lamps are switched off after a delay of 20 seconds. If the vehicle is locked after closing the doors, within
the 20 second period, the lamps go off immediately.
l When the interior lamps are on and the ignition is moved to positions I or II, the lamps go off immediately after
all doors have been closed.
l When the ignition switch is moved to the off position, the interior lamps are switched on for 20 seconds. This timer
is overridden if a door is subsequently opened.
l When the vehicle is unlocked and the doors are closed, the interior lamps can be activated for a further 20 second
period by pressing the 'unlock' button on the remote handset.
l When the vehicle is unlocked from a locked condition, the interior lamps are activated for a 20 second period.
This timer is overridden if a door is subsequently opened.
l If a door is left open, the interior lamps will remain on for 16 minutes. After this period, the BCU timer switches
the interior lamps off to prevent excessive battery drain.
The BCU uses a PWM operation of the interior lamps for the on/off conditions. The lamps are switched on with a 'soft
ramp' of 1.3 seconds. The lamps are switched off with a 'soft ramp' of 2.6 seconds. The soft on/off operation is
controlled by a semiconductor within the BCU.
Manual Operation
The interior lamps can be switched on or off using the manual switch for the front interior lamp. The front interior lamp
switch will switch all interior lamps, front and rear, on or off. If the interior lamps are on when the switch is pressed,
all interior lamps will go off. The on and off automatic switching conditions remain effective even when the manual
switch is used.
If the ignition switch is in position I or II and the front interior lamp switch is used to switch the interior lamps on, the
lamps will remain on continuously whilst the ignition is in position I or II. If the ignition switch is moved to the off
position, the interior lamps will be subject to the 16 minute BCU timer. The interior lamp is immediately switched off
when the vehicle is locked. After a locking procedure, the interior lamp automatic control is reinstated.
The rear interior lamp switch will switch the rear interior lamp only on or off.
Continuous Off
To prevent drain on the battery if the doors are to remain open for some time, the interior lamps can be turned off
permanently. This is stored in the BCU EEPROM and is also activated following a system power down or a reset of
the BCU.
To enter the continuous off condition, the front interior lamp switch must be pressed and held for more than 3 seconds.
The continuous off function can only be disabled by pressing the front interior lamp switch, after which, full automatic
control is resumed. When continuous off is active, the rear interior lamp switch can still be used to switch the rear
interior lamp only on or off.
LIGHTING
DESCRIPTION AND OPERATION 86-2-39
Crash Signal Operation
The BCU receives a crash signal on a hardwired connection from the DCU in the event of a crash of a severity to
activate the airbags. On receipt of this signal, the BCU activates the interior lamps which are on permanently and not
subject to the BCU timer.
The crash operation of the interior lamps can only be cancelled by operating the manual switch on the front interior
lamp or by locking and unlocking the vehicle.
LIGHTING
86-2-40 DESCRIPTION AND OPERATION
BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-1
BODY CONTROL UNIT DESCRIPTION AND OPERATION
BCU Component Location
BODY CONTROL UNIT
86-3-2 DESCRIPTION AND OPERATION
Description
General
The Body Control Unit (BCU) centralises the control of several body systems, reducing electrical complexity and
increasing overall system reliability. The BCU controls the routines of the following systems:
l Anti-theft alarm system (see Security section)
l Car/Key Memory
l Central door locking and child safety lock (see Security section)
l Door mirror control (see Body section)
l Headlamp wipers and washers (see Wipers and Washers section)
l Interior lighting (see Lighting section)
l Load disconnection
l Sunroof (see Body section)
l Approach Lamps (see Lighting section)
l Window regulators (see Windows section)
l Windshield wipers and washers (see Wipers and Washers section).
The vehicle type, equipment configuration and market specific features are specified to the BCU by means of coding
data via the diagnostics interface.
Load switching circuits for currents < 10 A consist of semiconductor switches within the BCU. The load switching
circuits for the headlamp and windshield wipers are subjected to a greater degree of loading (number of operating
cycles and current loading), so the switching is performed outside the BCU by relays.
Car/Key Memory
The car memory contains vehicle function settings that can be changed to suit market and customer preferences. In
some markets, some of the functions in the car memory are blanked out due to marketing and statutory requirements.
Where available, the settings can be changed using TestBook/T4.
The key memory is based on the car memory, and contains function settings that can be personalised to an individual
driver. Different drivers are recognised indirectly through the remote control transmitter in the key. Up to four different
keys can be recognised by the BCU. The key memory settings can be changed using TestBook/T4.
The BCU broadcasts driver recognition on the P bus and the K bus to the following control modules, which also
contain personalised key memory settings:
l Driver door module, for memorised door mirror settings
l Memory seat ECU, for memorised driver's seat and steering column settings
l Radio, for memorised tone, audio source and station settings.
The driver recognition messages contain the key number, the button pressed on the remote control and whether the
key is valid or not. The key number is contained in the unlock transmission of the remote control keys, so personalised
settings are only recalled after the vehicle has been unlocked with the remote control of one of the key numbers stored
in the key memory. If the vehicle is unlocked with the key in the driver's door lock, the BCU identifies the key as invalid
and control modules with personalised settings recall the last used setting. The BCU outputs the driver recognition
message when it detects:
l An 'unlock' command from a remote control (the signal is sent immediately so that the correct positions for seat,
door mirrors and steering column can be set)
l Any other actuation by remote control (when the remote control 'lock' command is detected, seat motion to a
memorised position is stopped)
l Operation of the central locking system by other than a remote control
l A change of state of the ignition switch
l A driver recognition enquiry from another control module.
The seat and steering column memories are coded with an automatic movement option for the driver's seat, door
mirrors and steering column. The options are:
l No automatic setting
l Automatically setting the positions in response to the remote control 'unlock' command
l Automatically setting the positions in response to the remote control 'unlock' command and opening of the
driver's door.
BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-3
Automatic movement of the seat can be stopped by pressing the remote control 'lock' button or any of the seat
adjustment or memory switches. Automatic movement can be restarted by pressing the remote control 'lock' button
again. Pressing the 'unlock' buttons (for selective central locking) and 'unlocking the boot' does not stop automatic
seat movement.
Storage of personalised settings is automatically updated for each setting change provided a valid remote control key
has been detected (interruption of the automatic recall movement of the driver seat, door mirrors and steering column
is not interpreted as a setting change). The last setting for the recognized driver is automatically stored in the key
memory area of the corresponding control module. If no valid remote control key has been detected, setting changes
are stored in a recall memory for retrieval when an invalid key is detected.
The following Table contains the car and key memory functions that can be changed (depending on market) using
TestBook/T4.
Control Unit Function Parameter Memory Type
ATC ECU Recirculation memory Active/ Inactive Car
Instrument pack Language of messages Canadian English; English;
French; German; Gulf States;
Italian; Japanese; Spanish; US
English
Car
Instrument pack Time display (time of day, arrival, timer) 12 or 24 hours clock Car
Instrument pack Consumption units Litres/100 km
mpg (UK)
mpg (USA); km/litre
Car
Instrument pack Travel units (range, distance) km (km/h)
miles (mph)
Car
Instrument pack Temperature unit Active/ Inactive Car
Instrument pack Ignition key warning (door open and key
in ignition starter switch)
Active/ Inactive Car
Light check module Daytime running lights Europe Active/ Inactive Car
Light check module Daytime running lights NAS Active/ Inactive Car
Light check module Headlamp courtesy delay time duration
(ignition key removed and headlight
flasher activated)
0 to 240 seconds at fixed
intervals
Car
PDC PDC sounder volume (rear sounder) Levels 1 (quiet) to 6 (loud) Car
Radio Tone, audio source and last station save Active/ Inactive Car
Driver seat module Automatic assumption of last driver
specific positions for seat, steering
column and exterior mirrors
Inactive
After unlocking door
After unlocking and opening door
Car
BCU Alarm arming/ disarming Lock and remote control
Only with remote control
Car
BCU Alarm armed acknowledgement,
acoustic
Active/ Inactive Car
BCU Alarm disarmed acknowledgement,
acoustic
Active/ Inactive Car
BCU Alarm armed acknowledgement, visual Active/ Inactive Car
BCU Alarm disarmed acknowledgement,
visual
Active/ Inactive Car
BCU Panic mode Active/ Inactive Car
BCU Visual acknowledgement of locking
without arming alarm, by lock and
remote control
Active/ Inactive Car
BCU Interior lamps on with multiple actuation
central locking system
Active/ Inactive Car
BCU Soft On/Off Active/ Inactive Car
BCU Automatic locking 2 minutes after
unlocking without opening
Active/ Inactive
BCU Automatic locking after driving off Active/ Inactive Car
BODY CONTROL UNIT
86-3-4 DESCRIPTION AND OPERATION
Load Disconnection
The BCU supplies various electrical loads on the vehicle, such as the glovebox lamp, reading lamps, luggage
compartment lamps, etc., that can be switched on and remain on when the vehicle is parked. A central load
disconnection feature in the BCU ensures the battery is not discharged in the event these loads are switched on
continuously. The trigger time after the ignition is switched off is 16 minutes and is independent of the sleep mode
timer.
The BCU also disconnects the following loads while the engine cranks, to maximise the available power from the
battery:
l Wipers
l Washer pump
l Headlamp cleaning
l Window regulators
l Sunroof.
If the one-touch function of a window or sunroof is active before the load disconnection, the function is not continued
when engine cranking stops.
Sleep Mode
To conserve power, the entire BCU goes into a 'sleep' mode 16 minutes after signal activity ceases and the ignition
is switched off. The typical current consumption of the BCU in sleep mode is 1.25 mA. In the sleep mode the BCU is
in a limited operational mode from which it can be awakened by certain relevant wake-up signals. After being
awakened, the BCU remains awake for 1 minute if no action is triggered. If an action is triggered, the BCU remains
awake for at least 16 minutes.
BCU Automatic locking threshold speed after
driving off
2.5 to 17.5 mph (4 to 28 km/h) at
fixed intervals
Car
BCU Driver's window one-touch open function Active/Inactive Car
BCU Driver's window one-touch close function Active/Inactive Car
BCU Front passenger window one-touch open
function
Active/Inactive Car
BCU Front passenger window one-touch
close function
Active/Inactive Car
BCU Rear windows one-touch open function Active/Inactive Car
BCU Rear windows one-touch close function Active/Inactive Car
BCU Window switch-off criterion Europe
NAS
Car
BCU Wiper reset (only without rain sensor) Active/Inactive Car
BCU Comfort function via remote control,
open all windows and sunroof
Active/Inactive Car
BCU Comfort function via remote control,
close all windows and sunroof
Active/Inactive Car
BCU Sunroof one-touch slide open function Active/Inactive Car
BCU Sunroof one-touch slide close function Active/Inactive Car
BCU Automatic locking after driving off Active/ Inactive Key
BCU Remote central locking actuation 1st press open driver's door, 2nd
press open all doors
1st press open all doors
Key
Control Unit Function Parameter Memory Type
BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-5
The BCU wakes up when it receives a signal from any of the following:
l The K bus
l Any door status switch (driver, front passenger, LH and RH rear doors)
l Bonnet status switch
l Central door locking switch
l Driver's door lock cylinder lock switch
l Driver's door lock cylinder unlock switch
l Interior lamp switch
l Lower tail gate opening switch
l Tilt alarm sensor
l Ultrasonic sensor
l Upper tail gate opening switch
l Upper tail gate status switch.
BODY CONTROL UNIT
86-3-6 DESCRIPTION AND OPERATION
BCU Harness Connectors
BCU Harness Connector C0660 Pin Details
Pin No. Description Input/Output
1 Battery power supply Input
2 Front interior lamp switch Output
3 Windscreen washer switch Input
4 Windscreen wipers switch 2 Input
5 Windscreen wipers switch 1 Input
6 LH (RHD) or RH (LHD) rear door open/close contacts Input
7 RH (RHD) or LH (LHD) rear door open/close contacts Input
8 to 11 Not used –
12 K bus Input/Output
13 Central door locking remote control serial bus Input/Output
14 Ground –
15 RH (RHD) or LH (LHD) rear window switch close selection Input
16 Not used –
17 LH (RHD) or RH (LHD) rear window switch open selection Input
18 LH (RHD) or RH (LHD) rear window switch close selection Input
19 Upper tail door open/close contacts Input
20 Windscreen wipers reset switch Input
21 Not used –
22 Lower tail door release switch Input
23 Auxiliary power supply Input
24 Central door locking switch Input
25 P bus Input/Output
26 RH (RHD) or LH (LHD) rear window switch open selection Input
M86 5978
C0661
C0662
C0660
BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-7
BCU Harness Connector C0661 Pin Details
BCU Harness Connector C0662 Pin Details
Pin No. Description Input/Output
1 Not used –
2 Bonnet switch Input
3 Not used –
4 Rapid tyre deflation signal Input
5 Alarm trigger from volumetric sensor Input
6 and 7 Not used –
8 Alarm trigger from tilt sensor Input
9 Not used –
10 Upper tail door external release switch Input
11 Upper tail door internal release switch Input
12 RH (RHD) or LH (LHD) rear window anti-trap sensor Input
13 SRS crash signal Input
14 Not used –
15 Windscreen wipers on Output
16 Windscreen wipers stage 2 Output
17 Headlamp wash/wipe relay Output
18 Not used –
19 Alarm LED Output
20 Alarm arm/disarm signal Output
21 Not used –
22 Lower tail door release relay Output
23 Road speed Input
24 LH (RHD) or RH (LHD) rear window anti-trap sensor Input
25 Windscreen wipers delay switch Input
26 Ground –
Pin No. Description Input/Output
1Ground –
2 RH (RHD) or LH (LHD) rear window motor open Output
3 Upper tail door release actuator Output
4 Battery power supply Input
5 LH (RHD) or RH (LHD) rear window motor open Output
6 Lock rear doors and fuel filler flap Output
7 and 8 Not used –
9 Servotronic activation Output
10 Battery power supply Input
11 Servotronic measurement resistor Input
12 RH (RHD) or LH (LHD) rear window motor close Output
13 Superlock rear doors and fuel filler flap Output
14 Unlock rear doors and fuel filler flap Output
15 LH (RHD) or RH (LHD) rear window motor close Output
16 Not used –
17 Alarm activation Output
18 Windscreen washer pump Output
19 Load disconnection Output
20 Interior lamps Output
BODY CONTROL UNIT
86-3-8 DESCRIPTION AND OPERATION
Diagnostics
Diagnostic monitoring is included in the operating software of the BCU and is performed on a continual basis. All of
the input and output signals which are relevant for diagnostics can be read out and injected using TestBook/T4.
Detected faults are stored in the non volatile memory (EEPROM) of the BCU.
All faults stored by the BCU are stored chronologically, with a fault counter, in a fault or information area of the
memory. Faults which positively point to one or more defective components are stored in the fault area. Faults which
do not positively point to a defective component are stored in the information area to provide information during
troubleshooting. The BCU ignores faults detected within 32 seconds of power up or when battery voltage is less than
9 V.
A distinction is made between sporadic and static faults. Sporadic faults are those which have occurred at least once,
and the cause of the fault message was no longer present at least one time. Static faults are faults which are still active
at the time diagnostics are performed.
The BCU can store up to 30 faults at any one time. If further faults are detected following the 30th fault they are
ignored. Faults can only be erased using TestBook/T4.
Up to 16 faults stored by the BCU are also stored in those modules connected to the BCU via the P bus, i.e. the driver
and passenger door modules and the sunroof module. Faults stored in the peripheral modules cannot be accessed
via the diagnostic socket. The faults in the peripheral modules are used for diagnosing modules after they are
removed from the vehicle.
COMMUNICATION DATA BUSES
DESCRIPTION AND OPERATION 86-4-1
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COMMUNICATION DATA BUSESDESCRIPTION AND OPERATION
COMMUNICATION DATA BUSES
86-4-2 DESCRIPTION AND OPERATION
Communication Data Buses Control
Diagram – Sheet 1 of 2
B = K bus; C = Diagnostic DS2 bus; D = CAN bus; J = Diagnostic ISO 9141 K line bus; K = I bus; L = M bus
M86 5801A
X
L
B
C
1
3
5
6
7
910
11
14
15
17
16
18 19 20 21 22
25 26
27
12
Y
2
23
24
D
8
13
4
J
K
COMMUNICATION DATA BUSES
DESCRIPTION AND OPERATION 86-4-3
1 ABS ECU
2 EAT ECU (ZF shown)
3 Air suspension ECU
4 Td6 ECM
5 Steering angle sensor
6 V8 ECM
7 Transfer box ECU
8 Instrument pack
9 LH xenon headlamp ECU
10 RH xenon headlamp ECU
11 Diagnostic socket
12 Low line ATC ECU
13 Air distribution motor
14 High line ATC ECU
15 Steering column lock ECU
16 Seat module
17 FBH
18 Face level air distribution motor
19 Windscreen air distribution motor
20 Footwell air distribution motor
21 Rear face level temperature blend motor
22 Ram air motor
23 Headlamp levelling ECU
24 Immobilisation ECU
25 TPM ECU
26 Rain sensor
27 SRS DCU
COMMUNICATION DATA BUSES
86-4-4 DESCRIPTION AND OPERATION
Communication Data Buses Control
Diagram – Sheet 2 of 2
B = K bus; K = I bus; M = P bus
M86 5802
X
K
5
6
12
11
10
9
7
8
13 14
15
16
22
21
20
19
1
Y
M
B
17
18
4
2
3
COMMUNICATION DATA BUSES
DESCRIPTION AND OPERATION 86-4-5
1 BCU
2 Front passenger door module
3 Driver door module
4 Sunroof ECU
5 Multi information display
6 ICE power amplifier
7 Navigation computer – Europe
8 Navigation computer – Japan
9 Radio
10 Radio/Cassette player
11 Video module
12 Multi function display
13 CD autochanger
14 PDC ECU
15 Light check module
16 Rotary coupler
17 Steering wheel LH switch pack
18 Steering wheel RH switch pack
19 Voice recognition ECU
20 Telephone module (NAS)
21 Telephone module (Non NAS)
22 Telephone eject box
COMMUNICATION DATA BUSES
86-4-6 DESCRIPTION AND OPERATION
Description
General
A number of different types of data bus are incorporated into the vehicle wiring harnesses for the transmission of
commands and information between ECU’s. The bus configuration installed on a particular vehicle depends on the
model and equipment level:
l Controller Area Network (CAN) bus. A network connected between the brake, powertrain, steering and
suspension related ECU’s
l Diagnostic buses. Two networks that, directly and indirectly, connect the diagnostic socket to all of the of the
ECU’s installed on the vehicle
l I bus. A network connected between ECU's of the 'Information' systems
l K bus. A network connected between ECU’s of the 'body' systems
l M bus. A network connected between the ATC ECU and motors on the heater assembly
l P bus. A network connected between the BCU and 'Peripheral' ECU's.
Serial interface circuits in the ECU’s transmit and receive commands and information on the buses as digital
messages. ECU’s connected to the same bus use a common protocol (format) and baud rate (transmission speed)
for the messages they transmit. The protocol and baud rate varies between bus networks. To enable messages to be
exchanged between ECU’s from different bus networks, the instrument pack provides a communication gateway. A
microprocessor in the instrument pack converts and/or re-transmits messages between bus networks.
The CAN bus is a high speed broadcast network where the ECU’s automatically transmit information on the bus every
few microseconds. The other buses are low speed networks which are mainly event driven, i.e. an ECU outputs a
message only in response to a request message from another ECU or a hard wired input from a switch or sensor.
A twisted pair of wires are used for the CAN bus and single wires are used for all of the other buses. Bus wires can
be repaired using crimped connections. The unwound length of CAN bus wires must not exceed 40 mm (1.6 in).
Data Bus Types
The diagnostic socket is connected to all of the ECU’s on the bus networks either directly, via the diagnostic buses,
or indirectly via the instrument pack. The diagnostic socket is located in a pocket in the fascia, next to the driver's side
A post.
Bus Baud rate (kbit/s) Protocol
CAN 500 SAE J1850
Diagnostic DS2 9.6 Corporate for diagnostics + ISO keyword 2000*
Diagnostic ISO 9141 K line 10.4 ISO keyword 2000 star + ISO keyword 2000 (for scan tools)
I 9.6 Corporate for body systems
K 9.6 Corporate for body systems
M 9.6 Corporate for body systems
P 9.6 Corporate for body systems
COMMUNICATION DATA BUSES
DESCRIPTION AND OPERATION 86-4-7
Diagnostic Socket
1 Hinged cover 2 Diagnostic socket
COMMUNICATION DATA BUSES
86-4-8 DESCRIPTION AND OPERATION
SECURITY
DESCRIPTION AND OPERATION 86-5-1
SECURITYDESCRIPTION AND OPERATION
Locking and Alarm Component Layout –
Sheet 1 of 2
1 Volumetric sensor
2 Alarm LED
3 Bonnet switch
4 BBUS
5 Door latch
6 Fuel filler flap actuator
7 Lower tail door latch relay
8 Ignition key/remote handset
9 Lower tail door release switch
10 Upper tail door external release switch
11 Upper tail door latch
12 Lower tail door latch
13 RF receiver/antenna amplifier
SECURITY
86-5-2 DESCRIPTION AND OPERATION
Locking and Alarm Component Layout –
Sheet 2 of 2
1 Tilt sensor
2 CDL switch
3 Upper tail door internal release switch
4 BCU
SECURITY
DESCRIPTION AND OPERATION 86-5-3
Immobilisation Component Layout
1 Immobilisation ECU
2 Starter motor
3 Ignition key/remote handset
4 Transponder coil
SECURITY
86-5-4 DESCRIPTION AND OPERATION
Description
General
The security system is split into three elements: the locking system, the alarm system and the immobilisation system.
The locking and alarm systems are controlled by the Body Control Unit (BCU). The immobilisation system is controlled
by a dedicated ECU. The arming and disarming of the alarm system is linked to the activation of the locking system.
The immobilisation system operation is independent of both the locking and the alarm systems.
Locking and Alarm Systems
All vehicles incorporate a remote handset Central Door Locking (CDL) system and an alarm system with perimetric
and volumetric protection functions. Specific features and modes of operation depend on the car/key memory settings
in the BCU.
The CDL system controls the locking and unlocking of the side doors and fuel filler flap, and the opening of the tail
doors. System features include automatic locking at a set vehicle speed and Single Point Entry (SPE).
The alarm system monitors for unauthorised entry, opening of doors and bonnet, vehicle movement and interference
with the electrical system, and sounds an alarm if an event is detected. The alarm system can be configured to
automatically arm and disarm with operation of the locking system. The locking and alarm systems incorporate:
l Actuators and switches in the door latches
l A bonnet switch
l A fuel filler flap actuator
l A CDL switch
l Upper tail door internal release switch
l Upper tail door external release switch
l Lower tail door release switch
l A lower tail door release relay
l Remote handsets
l A Radio Frequency (RF) receiver (market dependant)
l An infrared receiver (market dependant)
l An alarm Light Emitting Diode (LED)
l A Battery Backed Up Sounder (BBUS)
l A volumetric sensor
l A tilt sensor.
Door Latches
The side door latches are sealed units that incorporate separate actuators for locking and superlocking the doors, and
a Hall effect sensor to provide a door status signal for the BCU. The driver's door latch incorporates two additional
Hall effect sensors to provide signals of lock and unlock selections made with the ignition key in the door lock. Turning
the top of the ignition key rearwards sends a lock signal and turning the top of the ignition key forwards sends an
unlock signal. The driver and front passenger door latches communicate with the BCU via their respective door
modules and the P bus. The rear door latches are connected direct to the BCU.
The upper tail door latch incorporates a release actuator to open the upper tail door and a microswitch to provide an
upper tail door status signal. A black manual release wire is attached to the upper tail door latch to allow the latch to
be released in the event of actuator failure or loss of power. The end of the manual release wire is stowed in the inside
trim at the bottom edge of the upper tail door and is concealed by the trailing edge of the parcel shelf when the upper
tail door is closed.
Each lower tail door latch is connected to a release actuator mounted inside the tail door. A lever at the top of each
latch housing allows the latches to be released in the event of actuator failure or loss of power. The levers are only
accessible when the upper tail door is open.
SECURITY
DESCRIPTION AND OPERATION 86-5-5
Side Door Latch
Upper Tail Door Latch
1 Status microswitch 2 Release actuator
Bonnet Switch
The bonnet switch is a plunger operated switch installed in the engine compartment on the driver's side secondary
bulkhead. When the bonnet is closed, the bonnet presses the plunger into the switch housing and holds the switch
open. When the bonnet opens, the spring loaded plunger extends, which allows the switch to close and connect a
ground to the BCU. The switch can also be held open with the bonnet open, by pulling the switch up.
Fuel Filler Flap Actuator
The fuel filler flap actuator extends and retracts a wire reinforced plastic pin to lock and unlock the fuel filler flap. A
green manual release wire is attached to the pin to ensure the fuel filler flap can be released in the event of actuator
failure or loss of power. The end of the manual release wire is stowed in the soundproofing behind the trim panel
covering the rear fusebox.
SECURITY
86-5-6 DESCRIPTION AND OPERATION
CDL Switch
The CDL switch is a non latching push switch installed between the centre face vents on the fascia, below the hazard
warning switch. The CDL switch allows occupants to centrally lock the vehicle without arming the alarm. When the
CDL switch is pressed, a battery voltage signal is connected to the BCU.
Upper Tail Door Internal Release Switch
The internal upper tail door release switch is a non latching push switch installed on the centre console. The switch
allows the tail door to be opened from inside the vehicle. When the switch is pressed a ground is connected to the
BCU. The BCU only responds to the input when the CDL system is unlocked and the vehicle is stationary.
Upper Tail Door External Release Switch
The external upper tail door release switch is a microswitch installed in the license plate lamp housing in the bottom
edge of the upper tail door. The switch is operated by a lever connected to a rubber covered plate set into the outside
surface of the license plate lamp housing. When the switch is activated it connects a ground to the BCU. The BCU
only responds to the input when the CDL system is unlocked and the vehicle is stationary.
Lower Tail Door Release Switch
The lower tail door release switch is a non latching push switch installed under a rubber cover in the top edge of the
lower tail door. When the switch is pressed, a battery voltage signal is connected to the BCU. The BCU only responds
to the input when the upper tail door is unlatched and the vehicle is stationary.
Lower Tail Door Release Relay
The lower tail door release relay is installed on the rear fusebox. When the BCU receives a valid input from the lower
tail door release switch, it momentarily energises the relay to simultaneously activate the lower tail door release
actuators.
Remote Handsets
The remote handset is incorporated into the head of the ignition key. Up to four different remote handsets can be
initialised for use on the same vehicle.
The type of transmitter is market dependent and is either a Radio Frequency (RF) transmitter, operating at 315 or 433
MHz, or an infrared transmitter. RF transmitters communicate with the vehicle through the radio antenna integrated
into the rear window heater and have an operating range of 10 m (32.8 ft) minimum and up 30 m (98.4 ft) under
optimum conditions. Infrared transmitters communicate with the vehicle through an infrared receiver integrated into
the interior rear view mirror and have an operating range of 3 m (9.8 ft) minimum and up to 5 m (16.4 ft) under optimum
conditions.
Each remote handset incorporates a signal processor, transmitter and power supply in a dustproof and waterproof
housing. Buttons on the housing operate the remote functions. An LED on the housing flashes when a button is
pressed to confirm operation to the user. If the LED does not flash when a button is pressed the battery needs
recharging/replacing.
RF remote handsets have three operating buttons:
l The lock button, for locking and superlocking of the vehicle and convenience closing of the windows and sunroof
l The unlock button, for unlocking the vehicle and convenience opening of the windows and sunroof
l The tail door open button, for opening the tail door while the rest of the vehicle remains locked and for panic alarm
activation.
Infrared remote handsets only have two operating buttons, a lock button and an unlock button.
SECURITY
DESCRIPTION AND OPERATION 86-5-7
RF Remote Handset
1 Tail door open button
2 Lock button
3 Unlock button
4 LED
The remote handset functions as follows:
l One press of the lock button for superlocking
l Two presses of the lock button for no volumetric protection
l Press and hold the tail door switch for panic mode.
The power supply in the remote handset is provided by a single button cell battery on RF systems and two button cell
batteries on infrared systems. When the batteries need replacing the message 'KEY BATTERY LOW' will be
displayed in the message centre. When the batteries are replaced, the old ones should be removed and the new ones
installed within 1 minute or stored data will be lost and the remote handset will need to be re-initialised.
M86 5943
3
21
4
SECURITY
86-5-8 DESCRIPTION AND OPERATION
Battery Replacement on RF Remote Handset
1 Securing screw cover
2 Securing screw
3 Battery cover
4 Battery
5 Remote handset
Every signal from the remote handset contains the transmitter identification code and a rolling code. The BCU checks
the codes and only responds if the signal is from a valid transmitter. During vehicle production, the remote handsets
supplied with the vehicle are initialised to set their individual transmitter identification codes and synchronise their
respective rolling codes with the BCU. If a transmitter loses synchronisation with the BCU, or if a replacement or
additional remote handset is to be used with the vehicle, the initialisation procedure must be repeated. During the
procedure, all remote handsets for use with the vehicle must be initialised.
Initialisation Procedure
1 Ensure the vehicle is unlocked and the driver and front passenger doors are closed.
2 Install a key/remote handset in the ignition switch, then turn the ignition switch to position I and back to position
0 in less than 5 seconds to put the BCU into the initialisation mode. Continue the procedure within 30 seconds
of turning the ignition switch to position 0.
3 Remove the key/remote handset from the ignition switch.
4 Press and hold the unlock button for a maximum of 15 seconds. During this time, momentarily press the lock
button three times within 10 seconds.
5 Release both buttons.
6 Successful initialisation is indicated by the BCU locking then unlocking the vehicle. If this does not occur, repeat
step 4.
7 Repeat steps 4 and 5 with all other remote handsets belonging to the vehicle (4 maximum). Begin the
initialisation of each remote handset within 30 seconds of completing the previous initialisation, or the BCU will
drop out of the initialisation mode and the complete procedure will have to be started again.
RF Receiver (Where Fitted)
The RF receiver converts the signals from the RF remote handset into digital messages and transmits them to the
BCU. The RF receiver is integrated into the rear window antenna amplifier installed behind the inner trim on the top
left edge of the upper tail door. Operation of the receiver is powered by a permanent battery feed from the rear
fusebox.
M86 5944
1
2
3
5
4
SECURITY
DESCRIPTION AND OPERATION 86-5-9
Infrared Receiver (Where Fitted)
The infrared receiver converts the signals from the infrared remote handset into digital messages and transmits them
to the BCU. The infrared receiver is integrated into the interior rear view mirror, with the receiving diodes installed in
the red knob on the underside of the mirror. Operation of the receiver is powered by a permanent battery feed from
the passenger compartment fusebox.
Alarm LED
The alarm LED is installed in the red knob on the underside of the interior rear view mirror to provide a visual indication
of the alarm system status. Operation of the LED is controlled by the BCU.
Alarm System Status Indications
BBUS
The BBUS is installed in the rear corner of the engine compartment, on the driver's side, on a bracket attached to the
front wing. Depending on the BCU configuration, the BBUS can be used to produce the audio acknowledgement for
arming and disarming of the alarm system as well as the audio warning after an alarm has been triggered.
The BBUS is normally operated by a permanent battery feed from the passenger compartment fusebox. An integral
7.2 V rechargeable battery powers the BBUS if it is disconnected from the vehicle battery.
The BBUS sounds when it receives an alarm or acknowledgement signal from the BCU. While the alarm system is
armed, the BBUS also monitors the battery power supply and the arm/disarm signal line from the BCU, and operates
the sounder if the battery power supply or the arm/disarm signal line is disconnected. The BCU arms and disarms the
BBUS together with the rest of the alarm system.
Once an alarm has been triggered, the BBUS cycles the sounder on for 30 seconds and off for 15 seconds, for 5
minutes or until it receives a disarm signal from the BCU. If the alarm trigger is still present, the 5 minutes of on/off
cycles is repeated a further 2 times. The alarm output from the BBUS is either a constant tone or a modulated tone,
depending on the market. The continuous tone has a nominal value of 113 dBA when powered by the vehicle battery
and 108 dBA when powered by the integral battery. The modulated tone has a nominal value of 109 dBA when
powered by the vehicle battery and 104 dBA when powered by the integral battery.
Alarm Mode Alarm LED
Disarmed Off
Armed Flashes at 0.5 Hz (slow flashing)
Arming Rapid flashing for 10 seconds maximum, then begins flashing
at 0.5 Hz.
Alarm triggered Rapid flashing for 5 minutes then continues flashing at 0.5 Hz.
Re-arming less than 10 seconds after disarming On for 1 second
Disarming Off
Disarming after alarm Rapid flashing for 10 seconds then off
Emergency disarming On for 10 minutes
Vehicle locked (alarm not coded in BCU) On for 10 seconds
Unauthorised engine start detected by immobilisation system Rapid flashing until immobilisation system deactivated
SECURITY
86-5-10 DESCRIPTION AND OPERATION
BBUS Harness Connector
BBUS Harness Connector C0666 Pin Details
Volumetric Sensor
The volumetric sensor is installed behind openings in the rear interior lamp and monitors for intrusion into the
passenger compartment when the alarm is armed.
The volumetric sensor consists of a microcontroller, two acoustic transmitters and two acoustic receivers. One
transmitter/receiver pair faces forwards and one transmitter/receiver pair faces rearwards to ensure complete
coverage of the passenger compartment. The front transmitter/receiver pair are in a rubber mounting attached to the
microcontroller housing. The rear transmitter/receiver pair are in a remote rubber mounting and connected to the
microcontroller housing by a four wire lead.
The volumetric sensor is powered by a permanent battery feed from the passenger compartment fusebox. The BCU
activates and de-activates the volumetric sensor when it arms and disarms the alarm system. When the volumetric
sensor is active it outputs ultrasonic pulses from the transmitters and checks the echoes picked up by the receivers
for changes to the passenger compartment profile. If it detects a change of profile indicating movement in the
passenger compartment the volumetric sensor reports the alarm to the BCU.
Each time the volumetric sensor is activated it performs a self test. If there are no faults the volumetric sensor sends
an acknowledgement signal to the BCU. If the BCU does not receive the acknowledgement signal it de-activates the
volumetric sensor.
Pin No. Description Input/Output
1Ground –
2 Arm/Disarm signal Input
3 Battery power supply Input
4 Alarm activation Input
M86 5979
C0666
SECURITY
DESCRIPTION AND OPERATION 86-5-11
Volumetric Sensor
1 Front transmitter/receiver pair 2 Rear transmitter/receiver pair
Volumetric Sensor Harness Connector
Volumetric Sensor Harness Connector C0359 Pin Details
Pin No. Description Input/Output
1Ground –
2 Arm/Disarm signal Input
3 Alarm indication Output
4 Battery power supply Input
SECURITY
86-5-12 DESCRIPTION AND OPERATION
Tilt Sensor
The tilt sensor monitors for changes of vehicle attitude while the alarm is armed. The tilt sensor is installed under the
passenger seat in the BCU bracket.
The tilt sensor incorporates a two axis sensor controlled by a microprocessor. A permanent battery feed from the
passenger compartment fusebox powers the tilt sensor. The BCU activates and de-activates the tilt sensor when it
arms and disarms the alarm system. The tilt sensor receives activation and de-activation signals from the BCU.
The tilt sensor measures the longitudinal and transverse angles of the vehicle over a range of ±16° from the horizontal.
When the tilt sensor is activated, it stores the current angles in memory. If the vehicle changes attitude in either
direction by more than the limit the tilt sensor sends an alarm signal to the BCU, which triggers the BBUS. After an
alarm, the alarm limit is reduced to make the system more sensitive to any further change of attitude.
Alarm Triggering Limits
Each time the tilt sensor is activated it performs a self test. If there are no faults the tilt sensor sends an
acknowledgement signal to the BCU. If the BCU does not receive the acknowledgement signal it de-activates the tilt
sensor.
Tilt Sensor Harness Connector
Tilt Sensor Harness Connector C0960 Pin Details
Alarm Limit, Degrees
Longitudinal Transverse
First alarm 1.2 ± 0.55 1.4 ± 0.55
Second alarm 1.1 ± 0.55 1.3 ± 0.55
Pin No. Description Input/Output
1 Alarm indication Output
2 Arm/Disarm signal Output
3 Battery power supply Input
4 Arm/Disarm signal Input
5 Arm/Disarm signal Output
6 Not used –
M86 5981
C0960
SECURITY
DESCRIPTION AND OPERATION 86-5-13
Immobilisation System
The immobilisation system is a transparent system that prevents unauthorised starting of the vehicle by providing a
secure interface between the ignition switch and the Engine Control Module (ECM). It also prevents the engine from
starting if the steering lock is engaged or if the gearbox is not in park or neutral.
The immobilisation system consists of:
l The transponder in each ignition key
l The transponder coil around the ignition switch
l The immobilisation ECU.
Transponder
A transponder, consisting of a wireless Electronic Erasable Programmable Read Only Memory (EEPROM), is
incorporated into the head of each ignition key, including the 'wallet' ignition key. A password and key code in the
transponder provides each ignition key with a unique identification. As a further security measure, the transponder
contains a rolling code number written to it from the immobilisation ECU. The transponder key code and rolling code
are entirely separate from the remote handset codes.
The transponder is written to and read from by the immobilisation ECU via the transponder coil. The maximum range
for communication between the transponder and the transponder coil is approximately 20 mm (0.8 in).
Transponder Coil
The transponder coil is installed around the top of the ignition switch key barrel to enable communication between the
immobilisation ECU and the ignition key transponder. To operate the transponder the immobilisation ECU energises
the transponder coil with a 125 kHz ac current. This energises the transponder by electromagnetic induction.
Amplitude modulation is used to write data to the transponder.
CAUTION: The drive for the transponder coil is not capable of carrying battery voltage and care must be taken
when fault finding and probing the system otherwise permanent damage to the immobilisation ECU may
result.
Immobilisation ECU
The immobilisation ECU is installed on the driver's side of the gear selector assembly, underneath the centre console.
When it detects a valid transponder/ignition key in the ignition switch and is receiving a release signal from the steering
lock ECU, the immobilisation ECU sends a release signal to the ECM and energises the starter solenoid when the
ignition switch is turned to crank. The release signal to the ECM is a further rolling coded synchronised in the
immobilisation ECU and the ECM. If either the ECM or the immobilisation ECU are replaced they have to be re-
synchronised using TestBook/T4.
Up to 10 different transponders can be used with the immobilisation ECU. The 10 unique transponder key codes and
their associated rolling codes are generated during vehicle production and programmed into the immobilisation ECU.
The transponder of each ignition key supplied with the vehicle is then programmed with one of the key codes and its
associated rolling code. Once the immobilisation ECU and the transponders have been programmed they cannot be
over written. The 'spare' key codes and associated rolling codes are retained in the immobilisation ECU for future use.
The key codes and associated rolling codes are also recorded in a spares support database together with the Vehicle
Identification Number (VIN).
If an ignition key is lost, the key code of the related transponder should be disabled in the immobilisation ECU using
TestBook/T4. If the key is subsequently found, the transponder can be enabled again.
If a replacement or additional ignition key is ordered, the transponder of the new ignition key is programmed by the
spares supplier with one of the spare key codes and associated rolling code from the spares support database. The
immobilisation ECU recognizes the first use of the key code and automatically enables the new ignition key.
When a replacement immobilisation ECU is ordered it comes pre-programmed with the key codes and rolling codes
from the spares support database ready for use with the existing ignition keys once it has been synchronised with the
ECM.
A starter motor protection function is incorporated into immobilisation ECU. When the engine speed exceeds a
predetermined value, a relay inside the immobilisation ECU is disabled. This prevents damage to the starter motor in
the event of a sticking ignition switch or if crank is selected while the engine is running.
SECURITY
86-5-14 DESCRIPTION AND OPERATION
The immobilisation ECU is powered by a permanent battery feed from the passenger compartment fusebox. It also
receives an auxiliary power feed and an ignition power feed from the ignition switch. Power for the starter motor
solenoid is supplied to the immobilisation ECU when the ignition switch is in the crank position (on Td6 models) or on
a permanent feed from the passenger compartment fusebox (on V8 models). A connection with the K bus provides
the immobilisation ECU with engine speed and locking system status.
Immobilisation ECU Harness Connector
Immobilisation ECU Harness Connector C0059 Pin Details
Pin No. Description Input/Output
1 Starter power supply Output
2 Crank power supply from ignition switch (Td6) or
permanent power supply from battery (V8)
Input
3 Not used –
4 ECM data link Input/Output
5 Transponder coil Input/Output
6 Park/Neutral signal (Td6 only) Input
7 and 8 Not used –
9 Ground –
10 Permanent battery power supply Input
11 Auxiliary power supply from ignition switch Input
12 Transponder coil Input/Output
13 K bus Input/Output
M86 5982
C0059
SECURITY
DESCRIPTION AND OPERATION 86-5-15
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DESCRIPTION AND OPERATION
SECURITY
86-5-16 DESCRIPTION AND OPERATION
Alarm and Locking Control Diagram
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus; F = RF transmission; M = P bus
5
M86 5834A
1
A
B
2
3
4
7
8
10
12
13
14
15
16
17
18
19
20
21
22
23
25
26
27
28
29
31
6
24
30
M
11
9
C
F
SECURITY
DESCRIPTION AND OPERATION 86-5-17
1 Fuse
2 RF receiver/antenna amplifier
3 Rear window heater element/antenna
4 Ignition key/remote handset
5 CDL switch
6 Upper tail door interior release switch
7 Bonnet switch
8 Fuse 14, rear fusebox
9 Ignition key/infrared remote handset
10 Alarm LED (models with RF remote), alarm
LED and infrared receiver (models with infrared
remote)
11 Upper tail door latch
12 RH lower tail door latch
13 Lower tail door latch relay
14 LH lower tail door latch
15 Instrument pack
16 Diagnostic socket
17 RH rear door latch
18 Fuel filler flap actuator
19 LH rear door latch
20 Driver's door module
21 Driver's door latch
22 Front passenger door latch
23 Passenger door module
24 Upper tail door exterior release switch
25 Lower tail door release switch
26 BBUS
27 Tilt sensor
28 BCU
29 Volumetric sensor
30 Fuse 15, passenger compartment fusebox
31 Fuse 43, passenger compartment fusebox
SECURITY
86-5-18 DESCRIPTION AND OPERATION
Immobilisation Control Diagram – Diesel
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus
1 Fuse 31, passenger compartment fusebox
(ignition feed)
2 Ignition switch
3 Fuse 39, passenger compartment fusebox
(auxiliary feed)
4 Fuse 18, passenger compartment fusebox
(permanent battery feed)
5 Steering lock ECU
6 EAT ECU
7 Immobilisation ECU
8 Instrument pack
9 Diagnostic socket
10 Starter motor
11 ECM
12 Transponder coil
13 Remote handset/ignition key
M86 5836A
A
B
1
4
3
6
9
8
7
12
11
2
10
13
5
C
SECURITY
DESCRIPTION AND OPERATION 86-5-19
Immobilisation Control Diagram – Petrol
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus
1 Fuse 31, passenger compartment fusebox
(ignition feed)
2 Ignition switch
3 Fuse 39, passenger compartment fusebox
(auxiliary feed)
4 Steering lock ECU
5 EAT ECU
6 Diagnostic socket
7 Instrument pack
8 Starter motor
9 Starter motor relay
10 ECM
11 Immobilisation ECU
12 Transponder coil
13 Remote handset/ignition key
14 Fusible link 2, passenger compartment fusebox
15 Fuse 18, passenger compartment fusebox
(permanent battery feed)
M86 5837B
A
B
4
5
8
10
9
6
12
11
13
7
1
3
2
15
C
14
SECURITY
86-5-20 DESCRIPTION AND OPERATION
Operation
Locking System
The locking system allows the doors and fuel filler flap to be centrally locked and unlocked using the CDL switch, the
drivers door lock and the remote handset. The system has two locking states: locked and superlocked. Locking the
vehicle from inside using the CDL switch puts the system into the locked state. Locking the vehicle from the outside
using the driver's door lock or the remote handset puts the vehicle into the superlocked state.
When the vehicle is locked, the BCU:
l Energises the lock actuators in the side door latches to disengage the external door handles from the latches
l Energises the fuel filler flap actuator to extend the locking pin to secure the filler flap (all except NAS)
l Ignores inputs from upper tail door external release switch.
The BCU will lock the vehicle regardless of the position of the ignition switch and whether the key is in the ignition
switch or not. The upper tail door internal release switch remains enabled and individual side doors can be unlocked
using the internal door handle. From the locked state, the vehicle can be centrally unlocked using the CDL switch, the
remote handset or the driver's door lock.
When the vehicle is superlocked, the BCU:
l Energises the lock and the superlock actuators in the side door latches to disengage both the internal and the
external door handles from the latches
l Energises the fuel filler flap actuator to extend the locking pin to secure the filler flap
l Ignores inputs from both the external and the internal release switches of the upper tail door
l Ignores inputs from the CDL switch.
The BCU will only superlock the vehicle after the ignition key has been removed from the ignition switch and the
driver's door has opened. From the superlocked state, the vehicle can be centrally unlocked using the remote handset
or the driver's door lock.
Tail Door Opening
When the vehicle is locked or superlocked, operating the tail door release button on the remote handset causes the
BCU to actuate the upper tail door release actuator while leaving the remainder of the system in the locked/
superlocked condition.
Volumetric protection is disabled when the taildoor is opened.
SPE
With the vehicle superlocked and SPE enabled, when the BCU receives a request from the remote handset or the
driver's door lock it unlocks the driver's door and changes the rest of the system from the superlocked to the locked
state. When it receives a second unlock request, from the remote handset, the driver's door lock or the CDL switch,
the BCU unlocks the remainder of the system.
Automatic Locking
The BCU can be configured to automatically lock the system when the vehicle exceeds a set speed. The set speed
is selectable between 2.5 and 17.5 mph (4 and 28 km/h) in 2.5 mph (4 km/h) increments.
To guard against accidental unlocking, the BCU can also be configured to automatically lock (not superlock) the
system if no door switch, bonnet switch or CDL switch is activated within 2 minutes of unlocking the vehicle with the
remote handset.
Automatic Unlocking
If a crash that triggers the airbags occurs, the SRS DCU outputs a crash signal to the BCU. On receipt of the crash
signal the BCU outputs unlock signals to all the door latch actuators and the fuel filler flap actuator, irrespective of
their current locked state. Subsequent attempts to lock the doors are inhibited until the BCU has received an unlock
request.
SECURITY
DESCRIPTION AND OPERATION 86-5-21
Repetition Blocking
To protect the door latch actuators the BCU incorporates a repetition blocking feature. The BCU increments an
internal counter by one each time an actuation occurs and decrements the counter by one every 8 seconds. If the
counter exceeds 15, the BCU blocks further unlocking commands until the counter returns to 15 or less. The block is
ignored if the BCU receives a crash signal or the system goes from superlocked to locked. In addition to the counter
for the side doors, separate counters are maintained for each of the tail doors.
Lockout Protection
The vehicle cannot be locked when either of the front doors is open. The vehicle cannot be superlocked when the
driver's door is open.
Alarm System
The alarm system arms and disarms in conjunction with the superlocking and unlocking of the locking system.
Depending on the configuration of the BCU, the alarm system can be armed and disarmed when the locking system
is activated with the driver's door lock or the remote handset, or only with the remote handset. Visual and audible
confirmation of the alarm system arming and disarming, using the direction indicators and the BBUS, are also
configurable in the BCU.
When the vehicle is superlocked, the BCU sends an arming signal to the tilt sensor, which relays it to the BBUS and
the volumetric sensor. If the BCU does not receive an acknowledgement signal from the tilt sensor and the volumetric
sensor within 1 second, the BCU disables the associated alarm feature for the remainder of the armed cycle.
If the BCU detects two superlocking signals within 10 seconds, it disables volumetric sensing and tilt sensing. This
feature prevents accidental triggering of the alarm system during transportation of the vehicle or if a pet is left in the
vehicle.
Perimetric Sensing
When the alarm system arms, the BCU waits for 3 seconds before it begins monitoring the door status switches and
the bonnet switch for perimetric sensing. If a door or the bonnet have been left open, the BCU indicates this by flashing
the alarm LED for approximately 10 seconds. The input from the open switch is ignored until 3 seconds after it
changes to the closed state.
Volumetric Sensing
The BCU begins volumetric sensing 30 seconds after receipt of the superlock signal, the last door closes or
convenience closing stops, whichever occurs last.
If the alarm has been triggered, the BCU will ignore further volumetric sensor signals for the duration of the alarm.
The BCU resumes volumetric sensing 30 seconds after the alarm has stopped sounding.
Volumetric sensing and tilt sensing are disabled if the BCU receives a tail door open signal from the remote handset.
The BCU resumes volumetric sensing and tilt sensing 30 seconds after the upper tail door closes again.
Emergency Disarming
If the alarm has been triggered and cannot be disarmed with the driver's door lock or the remote handset, it can be
disarmed with the ignition switch as follows:
1 Use the ignition key to unlock the driver's door.
2 Sit in the vehicle and ensure all the doors are closed.
3 While the BBUS is still sounding, put the ignition key in the ignition switch and turn it to position I. The alarm LED
stays on instead of flashing.
4 After 10 minutes, the BBUS stops sounding, the alarm LED goes off, the locking system unlocks and the
immobiliser is made inactive.
Emergency disarming is configurable in the BCU.
SECURITY
86-5-22 DESCRIPTION AND OPERATION
Immobilisation System
When the vehicle is unlocked, with the driver's door lock or the remote handset, the BCU outputs a 'vehicle unlocked'
message on the K bus. The K bus message wakes the immobilisation ECU which energises the transponder coil
around the ignition switch. When the ignition key is close to, or inserted into, the ignition switch, the immobilisation
ECU reads the identity of the transponder. If the transponder/ignition key is valid, the immobilisation ECU outputs a
'valid key in ignition lock' message on the K bus.
When it detects the valid key in ignition lock message, the steering lock ECU disengages the steering column lock.
After disengaging the steering lock, provided it is also receiving a Park/Neutral signal from the Electronic Automatic
Transmission (EAT) ECU, the steering lock ECU sends a release signal to the immobilisation ECU. When the ignition
switch is turned from position 0 to position I, the immobilisation ECU interrogates the transponder for the password
and rolling code. If these are correct the immobilisation ECU sends the coded release signal to the ECM and, when
the ignition switch turns to position III, energises the starter solenoid to crank the engine. The immobilisation ECU also
writes a new rolling code to the transponder and verifies it to ensure it has been correctly received.
On petrol models, the immobilisation ECU energises the starter solenoid via the starter motor relay. The starter motor
relay is controlled by the ECM to provide the comfort starting function, which allows the engine to be started by a
momentary crank (position III) selection on the ignition switch. When the ignition switch turns to position III, the ECM
energises the starter motor relay, which energises the starter solenoid, until engine speed exceeds approximately 500
rev/min, or for 20 seconds, whichever occurs first.
If the vehicle is unlocked and the ignition key is not put into the ignition switch, the immobilisation ECU de-energises
the transponder coil and goes back into the sleep mode after approximately 60 seconds. When the ignition key is
subsequently put into the ignition switch and turned through 10° to 20°, the steering lock senses the movement and
sends a 'request electronic vehicle immobiliser status' message on the K bus. The message wakes the immobilisation
ECU, which energises the transponder coil and commences the transponder/ignition key identification and engine
mobilisation process as detailed above.
WINDOWS
DESCRIPTION AND OPERATION 86-6-1
WINDOWSDESCRIPTION AN D OPERATION
Windows Component Layout
1 Rear window motor
2 Rear window switch
3 Front window motor
4 Front passenger door module
5 Rear window anti-trap sensor
6 Front window anti-trap sensor
7 Driver door module
8 Front window motor
9 Rear window switch
10 Rear window motor
11 BCU
WINDOWS
86-6-2 DESCRIPTION AND OPERATION
Description
General
Electric windows are installed in all four doors. The front windows are controlled by their respective door modules
integrated into the window switch packs. The rear windows are controlled by the Body Control Unit (BCU). The BCU
and the door modules communicate with each other on the P bus.
Window operating features are market dependent and include one-shot opening and closing, convenience opening
and closing, and anti-trap. Market options for window operation are set centrally in the BCU.
Window Switches
Individual window switches are installed in each of the three passenger doors. Window switches for all of the windows,
and a child lock switch to isolate the rear windows, are installed in the driver's door.
All of the window switches have two switching positions in each direction. The first switching position operates the
window in the inching mode, where the window moves until the switch is released or until it reaches the fully open or
closed position. The second switching position operates the window in the one-shot mode.
Door Module Harness Connectors C2016 and C2017 Pin Details
Door Module Harness Connectors C2057 and C2058 Pin Details
Anti-trap Sensors
An anti-trap sensor is installed along the top of each window aperture, just outside the travel path of the window glass.
Each anti-trap sensor consists of a rubber covered contact strip connected to ground and to a power supply from the
door module (front windows) or BCU (rear windows). When the anti-trap sensor is pressed the resistance across the
contact strip is reduced. If a window is being closed and the door module/BCU detects a drop in resistance across the
associated anti-trap sensor, it immediately (in less than 20 milliseconds) reverses the window.
Pin No. Description Input/Output
1 Battery power supply Input
2Ground –
3 Not used –
4 Window motor close Output
5 Window motor open Output
6 Not used –
Pin No. Description Input/Output
1 P bus Input/Output
2 Interior illumination Input
3 Unlock signal from driver's door lock Input
4 Lock signal from driver's door lock Input
5 Not used –
6 Lock door actuator Output
7 Superlock door actuator Output
8 Interior illumination for door handle and door pocket LED's Output
9 Window anti-trap sensor Input
10 Not used –
11 Door open/close contacts Input
12 Unlock door actuator Output
WINDOWS
DESCRIPTION AND OPERATION 86-6-3
Window Regulators
Cable operated window regulators powered by an electric motor are installed in each of the doors.
Front Door Window Regulator
1 Window glass
2 Fixing point
3 Glass carrier
4 Rear mounting frame
5 Cable
6 Window motor
7 Front mounting frame
WINDOWS
86-6-4 DESCRIPTION AND OPERATION
Rear Door Window Regulator
1 Fixing
2 Mounting frame
3 Glass carrier
4 Window glass
5 Window motor
WINDOWS
DESCRIPTION AND OPERATION 86-6-5
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DESCRIPTION AND OPERATION
WINDOWS
86-6-6 DESCRIPTION AND OPERATION
Windows Control Diagram
A = Hardwired connection; B = K bus; C = Diagnostic ISO 9141 K line bus; M = P bus
M86 5959A
1
3
4
5
6
7
9
10
11
12
14
16
17
18
19
21 20
2
A
M
13
15
8
B
C
WINDOWS
DESCRIPTION AND OPERATION 86-6-7
1 Ignition switch
2 Front passenger window anti-trap sensor
3 Fuse 24, passenger compartment fusebox
4 Fuse 11, passenger compartment fusebox
5 Driver window anti-trap sensor
6 Driver door module
7 Driver window motor
8 Fuse 60, passenger compartment fusebox
9 Instrument pack
10 Diagnostic socket
11 RH rear window motor
12 RH rear window anti-trap sensor
13 RH rear window switch
14 LH rear window motor
15 LH rear window anti-trap sensor
16 LH rear window switch
17 BCU
18 RF receiver
19 Fuse 41, passenger compartment fusebox
20 Front passenger door module
21 Front passenger window motor
WINDOWS
86-6-8 DESCRIPTION AND OPERATION
Operation
General
Electric window operation using the window switches is enabled while the ignition switch is in positions I and II, and
for 16 minutes after switching from position I to position 0. Window operation is immediately disabled when a front
door is opened
End of Travel Shut off
End of travel shut off for the window motors is determined by monitoring the current draw of the motors. Each time it
switches on a window motor, the door module or BCU measures the window motor current for 22 milliseconds, in 2
milliseconds intervals. The maximum value measured within that time is stored as the switch-on current, which must
be 5 A minimum. When the window motor current next exceeds the switch-on current minus 2 A, the door module/
BCU assumes the window has reached the end of its travel and, after 0.5 second, switches off the power supply to
the window motor, even if a window switch is still being activated.
Measuring the switch-on current for each switching operation automatically compensates for changes of load with
varying ambient conditions etc.
To protect the window motors from overheating if the end of travel shut off function fails, window motor activation in
both directions is limited to 8 seconds.
One-shot Opening and Closing
One shot opening and closing is activated by selecting the second switching positions on the window switch. One-
shot opening and closing is enabled on all windows except on Australia models. On Australia models, all one-shot
operation is disabled except for driver's window closing.
Anti-trap
The anti-trap function is enabled for window closing in both the inching and one-shot modes. If an anti-trap sensor is
activated while a window is closing, the window motor is reversed for 0.5 second.
UK models feature a longer reversing time after a trap detection. The reversing time is proportionate to the preceding
closing time and varies between 0.5 and 2.0 seconds.
In an emergency, e.g. if the anti-trap sensor is faulty, the anti-trap function can be overridden by holding the window
switch in the one-shot closed position.
WINDOWS
DESCRIPTION AND OPERATION 86-6-9
Convenience Opening and Closing
Convenience opening and closing is enabled provided the ignition switch is not in position I or above. The windows
and sunroof (where fitted) can be opened and closed in sequence, while unlocking and locking the vehicle, using the
driver's door lock or the remote handset.
Convenience closing begins after a time delay of 1.5 seconds when the door lock is held in the lock position or the
remote handset lock button is pressed and held. The anti-trap function is enabled during convenience closing. The
closing operation also stops immediately the door lock is released from the lock position or the remote handset lock
button is released. The window motors are switched in pairs, with the rear ones switched first followed 1 second later
by the front ones. The sunroof begins closing when all of the windows are closed or 3.5 seconds after convenience
closing started, whichever occurs first.
There is no convenience closing on NAS vehicles.
Convenience opening begins after a time delay of 2.5 seconds when the door lock is held in the unlock position or the
remote handset unlock button is pressed and held. The opening operation stops immediately the door lock is released
from the unlock position or the remote handset unlock button is released. The window motors are switched in pairs,
with the front ones switched first followed 1 second later by the rear ones. The sunroof begins opening 3.5 seconds
after convenience opening started.
Operating the windows and sunroof in sequence allows a degree of selective operation, e.g. the windows can be
closed and the sunroof left open when locking the vehicle and using convenience closing.
Repetition Blocking
To prevent the window motors from overheating, the door modules and the BCU record the run time for each motor
they control. The run time, in seconds, is added to a counter on completion of each activation, and one second is
deducted from the counter for every three seconds the window motor is inactive. If the counter exceeds 60 seconds,
no new activation for the window motor is accepted until the counter is below 60 seconds again. The only exception
is a reversing operation triggered by the anti-trap function, which is always accepted regardless of the counter value.
WINDOWS
86-6-10 DESCRIPTION AND OPERATION
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-1
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ENTERTAINMENT AND INFORMATION SYSTEMSDESCRIPTION AND OPERATION
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-2 DESCRIPTION AND OPERATION
MID Audio System Component Location
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-3
1 Side window aerial amplifier
2 Rear screen aerial amplifier
3 MID unit
4 Cassette player and radio unit
5 CD player and radio unit
6 Mini disc player and radio
7 Rotary coupler
8 Steering wheel controls
9 CD autochanger
10 Suppressor
11 Suppressor
12 Power amplifier
13 DSP amplifier
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-4 DESCRIPTION AND OPERATION
MID Audio System Control Diagram
A = Hardwired connection
M86 5860
A
12
3
4
6
7
8
9
10
11
12
13
14
15
5
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-5
1 Steering wheel controls
2 Rotary coupler
3 MID unit
4 Side window aerials
5 Side window aerial amplifier
6 Rear window aerial amplifier
7 Rear window aerials
8 Suppressor
9 Suppressor
10 DSP amplifier
11 Power amplifier
12 Cassette player and radio unit
13 Mini disc player and radio
14 CD player and radio unit
15 CD autochanger
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-6 DESCRIPTION AND OPERATION
Multi-Function Display Audio
Component Location
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-7
1 Video module
2 Television aerial amplifier
3 Rear screen radio aerial amplifier
4 Side screen radio diversity aerial amplifier
5 Multi-Function Display unit
6 Rotary coupler
7 Steering wheel switches
8 CD autochanger (optional)
9 Television aerial amplifier
10 Suppressor
11 Suppressor
12 Radio unit
13 Amplifier (optional)
14 DSP (optional)
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-8 DESCRIPTION AND OPERATION
Multi-Function Display Audio Control
Diagram
A = Hardwired connection
M86 5861
A
8
10
11
12
14
15
16
2
7
6
5
4
3
1
18
17
9
13
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-9
1 Steering wheel switches
2 Video module
3 Multi Function Display (MFD)
4 Side window aerials
5 Alternative side screen aerial amplifier for
parked heating
6 Television aerial amplifier
7 Television aerial amplifier
8 Side screen television aerial and radio diversity
tuning radio aerial
9 Side screen radio diversity tuning aerial
amplifier
10 Rear screen aerial amplifier
11 Rear screen
12 Suppressor
13 Suppressor
14 DSP
15 Power amplifier
16 Radio module
17 CD autochanger
18 Rotary coupler
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-10 DESCRIPTION AND OPERATION
Screen Aerial Components
1 Side screen Television and diversity radio
aerials
2 Rear screen aerial amplifier
3 Side screen television aerial
4 Television aerial amplifier
5 Alternative television aerial for telestart
6 Rear screen aerial suppressor
7 Rear screen aerial suppressor
8 Television aerial amplifier
9 Rear screen radio aerial
10 Side screen radio diversity tuning aerial
amplifier
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-11
Speaker System Component Location
1 Front LH door low range unit
2 Front LH door mid range unit
3 Front LH tweeter
4 Front centre speaker
5 Front RH tweeter
6 Front RH door mid range unit
7 Front RH door low range unit
8 Rear RH low range door speaker
9 Sub woofer
10 Rear LH low range door speaker
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-12 DESCRIPTION AND OPERATION
Base Speaker Control Diagram
A = Hardwired connection
1 CD radio unit
2 Cassette radio unit
3 Mini disc radio unit
4 Radio unit
5 Front RH low range speaker
6 Front RH mid range speaker
7 Rear RH low range speaker
8 Rear LH low range speaker
9 Front LH mid range speaker
10 Front LH low range speaker
M86 5757
1
2
3
5
6
78
9
10
A
4
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-13
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ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-14 DESCRIPTION AND OPERATION
Power Amplifier Speaker System Control
Diagram
A = Hardwired connection
M86 5758
1
2
3
4
5
6
7
8
9
10
A
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-15
1 Power amplifier
2 Centre speaker
3 Front RH tweeter
4 Front RH mid range
5 Front RH low range
6 Rear LH low range
7 Rear LH low range
8 Front LH low range
9 Front LH mid range
10 Front LH tweeter
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-16 DESCRIPTION AND OPERATION
DSP Amplifier Speaker System Control
Diagram
A = Hardwired connection
M86 5759
1
2
3
4
5
6
8
9
10
11
7
A
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-17
1 DSP
2 Centre speaker
3 Front RH tweeter
4 Front RH mid range
5 Front RH low range
6 Rear RH low range
7 Sub-woofer
8 Rear LH low range
9 Front LH low range
10 Front LH mid range
11 Front LH tweeter
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-18 DESCRIPTION AND OPERATION
Audio Systems
Introduction
New Range Rover has two distinct types of audio system. One system is based around the Multi Information Display
(MID) while the other is based around the Multi-Function Display (MFD).
It is also possible to specify extras to the audio system to extend its capabilities. These options include:
l Telephone
l CD autochanger
l Amplifier
l Digital signal processor (DSP)
l Satellite navigation (MFD only)
l Television / Teletext (MFD only)
l Voice recognition system (navigation and telephone).
MID Audio System
As stated the low line audio system is based around the Multi information display unit. The system comprises:
l MID unit
l Cassette unit, mini disc unit or CD unit
l CD auto changer (optional)
l Radio unit
l Telephone (optional)
l Digital signal processor (DSP-optional)
l Speakers
l Amplifier (optional).
All the low line systems use the MID unit as a control panel for the whole system. The MID is located in the centre of
the fascia. The MID unit incorporates a two line LCD display with controls that allow the user to control the radio,
cassette player, CD player/auto changer, trip computer, telephone and amplifier (DSP). Depending upon the
customers selection of options the MID has four different front panels to allow for control of the different options. These
are as follows:
l DSP and Phone
l Phone No DSP
l DSP No Phone
l No DSP No Phone.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-19
MID Controls
1 Tape, CD or Mini Disc slot
2 Audio/DSP button
3 Telephone operation button
4 Computer/clock settings button
5 Multi function toggle button
6 Multi function toggle button
7 Multi function toggle button
8 Multi function toggle button
9 Multi function toggle button
10 On/off rotary volume control
11 Search and Memory button
Six rocker buttons are located below the MID. Each rocker button has a pressure point on the left and the right. There
are effectively 12 switching levels for this button unit. Arranged to the right next to the display are the buttons for the
selection of AUDIO, DSP, TELEPHONE, CLOCK and BC (on-board computer). The AUDIO button has one pressure
point each on the left and right. In the case of versions with DSP, the left pressure point is assigned to AUDIO and
the right to DSP. The buttons for TELEPHONE with the handset symbol and BC with the CLOCK are laid out as rocker
buttons. To the left next to the display is a rocker button for the search and scan functions. The button for the manual
search function is inserted in the centre of this rocker button. A rotary increment sensor is used to control AUDIO and
the hands-free speaking feature of the telephone volume, as well as the ON / OFF switch for the AUDIO system. This
is carried out by means of an increment sensor with an integrated push switch. The rotary controller has 36
incremental steps of 10° each.
The MID lighting is controlled by a photo-transistor sensor. The brightness of the lighting can also be influenced
manually by the instrument lighting dimmer. When the vehicle lighting is switched off, the display brightness is
governed exclusively via the sensor, this gives a daytime minimum brightness of 60 % of the control range is defined.
When the instrument dimmer is switched on, the controlling range from the daytime minimum brightness onward is
expanded by the dimension of the dimmer position. The dimmer position is taken from the "dimming" message. With
"light off" the LED function indications are activated at the maximum level and with "light on" with the value of the day/
night threshold, irrespective of the photo-transistor.
Control signals for the MID are sent along the I-bus.
MID Harness Connector C0241 Pin Details
M86 5755
Radio 1
12
FM RDS
*
AM
TONE
1212
MODESC
9
8765
1
10
4
3
2
11
12
m
AUDIO DSP
TEL
BC
Pin No. Description Input/Output
1Ground –
2 Permanent power supply from battery Input
3 Interior illumination Input
4 I bus Input/Output
5 to 7 Not used –
8 Auxiliary power supply Input
9 to 12 Not used –
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-20 DESCRIPTION AND OPERATION
Diagnostics
The MID is capable of being subjected to diagnostics. The principle applies of finding the smallest replaceable unit
via the diagnostics computer (TestBook/T4). The instrument pack serves as a gateway between the diagnostics bus
and the I-bus. The messages from TestBook/T4 are converted by the instrument pack into the respective I-bus format.
The MID detects the diagnostics mode by means of the diagnostics computer address. Normal operation is
maintained during the diagnostics mode. MID diagnostics are subdivided into two categories:
l Device identification
l Self-diagnostics with error storage.
Control unit identification is stored in the EEPROM of the MID and can be called up by means of the diagnostics tester.
The data is programmed at the point of manufacturer.
Errors detected by the MID are stored in the EEPROM. The errors are stored in the order of their occurrence. Each
error is assigned an error code. In order to avoid the entry of "false errors", the error memory is not written to in the
first 500 ms after the power-on reset. The frequency counter is incremented with each detected error. The error type
is set to "momentarily present". After the error is corrected, the error type is set to "sporadic (not momentarily
present)". The error frequency counter stores a maximum of 31 errors. Once this limit is reached, the error type
remains constantly on "momentarily present". Any fault codes can only be removed by the manufacturer.
Multi-Function Display Audio System
The High Line audio option comprises:
l Multi-Function Display head unit
l Radio unit
l Speakers
l Amplifier.
Multi-Function Display
Multi-Function Display Controls
1 Information button
2 Cassette eject button
3 Telephone button
4 Clock/direction button
5 Tone button
6 Search button
7 Menu access button
8 Right hand rotary controller
9 Left hand rotary controller
10 Mode button
11 Wave band change button
12 Pre-set button
13 Pre-set button
14 Pre-set button
M86 5753
9
10
11
12
13
14
1
2
3
4
5
6
7
8
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-21
The Multi-Function Display forms the basis of the high line audio system. It communicates with the rest of the audio
system on the I/K-Bus. The Multi-Function Display controls all the radio, CD changer (optional) and cassette functions.
The cassette unit is located behind the display panel and is accessed by pressing the “tape eject button”. This causes
the screen to move down and tilt slightly forward to reveal the cassette slot and eject the cassette. There is no option
for a single slot CD player with the Multi-Function Display audio system. All other components of the audio system
are the same as the low line system.
Diagnostics for the MFD are described in the navigation section.
MFD Harness Connector C0815 Pin Details
MFD Harness Connector C0816 Pin Details
Pin No. Description Input/Output
1 Red video signal Input
2 Red video ground –
3 Green video signal Input
4 Green video ground –
5 Blue video signal Input
6 Blue video ground –
8 Permanent power supply from battery Input
Pin No. Description Input/Output
1 Interior illumination Input
2Ground –
3 LH audio positive Output
4 LH audio negative Output
5 Not used –
6 I bus Input/Output
7 Permanent power supply from battery Input
8 Not used –
9 RH audio negative Output
10 RH audio positive Output
11 and 12 Not used –
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-22 DESCRIPTION AND OPERATION
Common Components
Both systems share some common components, these are detailed bellow.
Radio Module
The radio unit for the 'Low' system is located in the cassette, CD or Mini disc player unit. The radio unit for the 'High'
line audio system is separate from the head unit and is located in the left hand side of the luggage compartment.
Radio Module
Both radio systems offer the option of Business units or Professional. Both units offer six preset buttons allowing the
presetting of 6 radio stations on FM, 6 radio stations on MW and 6 Radio stations on LW to the preset buttons on the
Multi-function Display . The “Business” system provides standard AM/FM tuner capabilities (RDS Traffic information
Etc.) while the “professional”system has two separate tuners built in to give improved radio reception through diversity
tuning. This involves one of the tuners providing the selected programme while the other tuner continuously searches
for a stronger signal for the selected broadcast station and for other RDS stations that can be received.
Radio Module Harness Connector C0818 Pin Details
Pin No. Description Input/Output
1 RH rear audio positive Output
2 RH front audio positive Output
3 LH front audio positive Output
4 LH rear audio positive Output
5 RH rear audio negative Output
6 RH front audio negative Output
7 LH front audio negative Output
8 LH rear audio negative Output
9 I bus Input/Output
10 Telephone mute Input
11 Not used –
12 Ground –
13 Radio on signal Output
14 Interior illumination Input
15 Permanent power supply from battery Input
16 Auxiliary power supply Input
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-23
Radio Module Harness Connector C0991 Pin Details
Radio Module Harness Connector C1912 Pin Details
Pin No. Description Input/Output
1 Not used –
2 LH and RH audio negative Input
3 to 7 Not used –
8 LH audio positive Input
9 RH audio positive Input
10 TV RH audio positive Input
11 TV LH audio positive Input
12 TV LH and RH audio negative Input
Pin No. Description Input/Output
1 LH audio positive Input
2 LH audio negative Input
3 and 4 Not used –
5 Navigation audio positive Input
6 Not used –
7 RH audio positive Input
8 RH audio negative Input
9 and 10 Not used –
11 Navigation audio negative Input
12 Not used –
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-24 DESCRIPTION AND OPERATION
Screen Mounted Aerials
1 Side window television and radio diversity
aerials
2 FM aerial amplifier
3 Side window television aerial
4 Television aerial amplifier
5 Television aerial amplifier with parked heating
6 Suppressor
7 Suppressor
8 Television aerial amplifier
9 Side window FM aerial diversity amplifier
The “RDS radio” system uses the heated rear screen element as the radio antenna. The signal is processed by an
amplifier before being passed through to the head unit. This antenna and amplifier is also used receive and process
signals from the remote handset to lock/unlock and arm/disarm the alarm. Because of this there are two types of
amplifier to accommodate the different frequencies used with the remote in different markets. This standard amplifier
is located in the tailgate at the top left hand corner.
The “RDS Hi Fi” system use a second antenna fitted in the left hand window of the luggage compartment to achieve
the diversity function. The amplifier for this antenna is located left hand side of the luggage compartment behind the
trim panel near the wheel arch.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-25
CD Autochanger
Both systems are capable of controlling a six disc CD autochanger. The autochanger is controlled on the I/K Bus and
is located at the rear of the passenger compartment glove box.
CD Autochanger Harness Connector C0941 Pin Details
CD Autochanger Harness Connector C1353 Pin Details
Pin No. Description Input/Output
1Ground –
2 Permanent power supply from battery Input
3 I bus Input/Output
Pin No. Description Input/Output
1 Left audio positive Output
2 Left and right audio negative Output
3 Not used –
4 Right audio positive Output
5 and 6 Not used –
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-26 DESCRIPTION AND OPERATION
Amplifiers
The basic audio system has no amplifier. The system drives two speakers, one in each rear door, and two speakers
(one woofer and one tweeter) in each of the front doors.
The “Hi Fi” system has a conventional power amplifier located in the left hand side of the luggage compartment. The
amplifier drives two speakers in each of the rear doors, three speakers in each of the front doors and a centre speaker
connected across the two front mid-range speakers.
Amplifier Harness Connector C2077 Pin Details
Pin No. Description Input/Output
1 LH rear door low range speaker negative Output
2 LH rear door low range speaker positive Output
3 LH front door low range speaker negative Output
4 LH front door low range speaker positive Output
5 Permanent power supply from battery Input
6 and 7 Not used –
8 RH rear audio positive Input
9 RH front audio positive Input
10 Radio on signal Input
11 RH front tweeter positive Output
12 RH front tweeter negative Output
13 RH rear door high range speaker positive Output
14 and 15 Not used –
16 RH rear audio negative Input
17 RH front audio negative Input
18 and 20 Not used –
21 RH rear door high range speaker negative Output
22 RH front door low range speaker negative Output
23 RH front door low range speaker positive Output
24 RH rear door low range speaker negative Output
25 RH rear door low range speaker positive Output
26 Ground –
27 and 28 Not used –
29 LH rear audio negative Input
30 LH front audio negative Input
31 LH rear door high range speaker positive Output
32 LH rear door high range speaker negative Output
33 LH front tweeter positive Output
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-27
34 LH front tweeter negative Output
35 and 36 Not used –
37 LH rear audio positive Input
38 LH rear audio positive Input
39 LH front door mid range speaker negative Output
40 LH front door mid range speaker positive Output
41 RH front door mid range speaker negative Output
42 RH front door mid range speaker positive Output
Pin No. Description Input/Output
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-28 DESCRIPTION AND OPERATION
Digital Signal Processor
The top “Hi Fi” option has a digital signal processor (DSP) amplifier which is located in the left hand side of the luggage
compartment. It drives two speakers in each of the rear doors, three speakers in each of the front doors, a centre
speaker connected across the two front mid-range speakers and two dual voice-coil sub-woofers in the luggage
compartment. It can also use digital signal processing techniques to simulate a Concert Hall, a Jazz Club, a Cathedral
or one of three user defined settings. These functions are controlled from the Multi-Function Display via the DSP
option.
DSP Harness Connector C0491 Pin Details
DSP Harness Connector C0492 Pin Details
Pin No. Description Input/Output
1 Subwoofer 1 positive Output
2 Subwoofer 2 positive Output
3 LH rear door low range speaker positive Output
4 Radio on signal Input
5 RH rear door low range speaker negative Output
6 Subwoofer 4 negative Output
7 Subwoofer 3 negative Output
8 Permanent power supply from battery Input
9 Subwoofer 1 negative Output
10 Subwoofer 2 negative Output
11 LH rear door low range speaker negative Output
12 RH rear door low range speaker positive Output
13 Subwoofer 4 positive Output
14 Subwoofer 3 positive Output
15 Ground –
Pin No. Description Input/Output
1 Not used –
2 Telephone audio negative Input
3 and 4 Not used –
5 I bus Input/Output
6 and 7 Not used –
8 RH front audio negative Input
9 LH front audio negative Input
10 Not used –
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-29
DSP Harness Connector C0493 Pin Details
11 Telephone audio positive Input
12 to 14 Not used –
15 Telephone on Input
16 Not used –
17 RH front audio positive Input
18 LH front audio positive Input
Pin No. Description Input/Output
1 LH front door low range speaker positive Output
2 LH front door low range speaker negative Output
3 Not used –
4 RH front door mid range speaker negative Output
5 LH front door mid range speaker positive Output
6 to 8 Not used –
9 RH front door mid range speaker positive Output
10 LH front door mid range speaker negative Output
11 RH rear door high range speaker + Output
12 RH front tweeter positive Output
13 RH front door low range speaker positive Output
14 LH front tweeter positive Output
15 LH front tweeter negative Output
16 LH rear door high range speaker negative Output
17 and 18 Not used –
19 LH rear door high range speaker positive Output
20 to 23 Not used –
24 RH rear door high range speaker negative Output
25 RH front tweeter negative Output
26 RH front door low range speaker negative Output
Pin No. Description Input/Output
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-30 DESCRIPTION AND OPERATION
MID Audio Operation
All of the functions of the MID Audio are controlled by the switches around the MID unit. Additional control is available
in the form of steering wheel mounted switches to alter the volume, change pre-set radio station, fast forward tape or
CD tracks.
Steering Wheel Switches
Radio Operation
The radio is accessed by pressing the rotary controller on the MID. The radio can be tuned by pressing the arrow
buttons on the left of the MID (right arrow tunes up the scale left tunes down the scale). The 'M' button in the middle
of the arrow keys saves the tuned station to a memory.
Cassette Operation
The cassette is operated by inserting the tape into the tape slot. Once in the tape will start to play. The cassette player
is an auto-reverse tape player and will continue to play the tape from one side to the next until the tape is ejected or
the mode has changed to radio or CD player. To access a tape that is already in the cassette player from the radio or
CD autochanger press the button marked “Mode” on the far right hand side of the MID.
Functions that are available while in the cassette mode are:
l Side
l Dolby
l SC
l Mode.
Using the side option changes the tape from the current side being played to the other side of the tape.
Pressing the SC option changes the display to SC*, this activates the intro scan function. The cassette player will play
the introduction 10 seconds of each track on the tape. When the desired track is reached pressing this button again
will stop scanning the intros and start playing the tape from that point.
The cassette player also has the option to switch Dolby™ noise reduction from Dolby C to B or off by toggling the
switch labelled with Dolby in the MID.
The other functions (radio and CD player) are accessed by pressing the “Mode” button.
Mini Disc Operation
Once the Mini Disc (MD) is in the player, press the mode button to access the MD mode. The MID will display the
track number and the time. There is a slight delay between starting the player and the audio beginning as the player
has to read the audio data from the disc.
It is also possible to search for a specific track by pressing the direction key. A single press will advance the disc on
a track. Holding the button in fast forwards/rewinds through the current track. Releasing the key resumes playing the
track from that point.
The MD player has two special functions it can perform:
l Track scan function
l Random play function
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-31
The scan function allows the user to listen to the first few seconds of all the tracks on the disc. The scan function is
accessed by pressing the button on the MID marked SC. An asterix will display next to the SC symbol to denote that
it is switched on. Once on the player will access each track in turn and play the first ten seconds then move on to the
next. To interrupt this and play a selected track the user must press the SC button again.
The Random play function allows the user to play the contents of the MD in a completely random order. This is
achieved by press the button on the MID marked RND. Again an asterix will appear next to the RND in the MID to
denote that this function is active. Tracks can be searched for using the direction keys but selection will not be
sequential, it will follow the random order in the units memory. De-selection of the random mode is achieved by
pressing the RND button again.
Compact Disc (CD) Player Operation
With a CD in the player, press the mode button to access the CD mode. The MID will display the track number (01)
and the time.
To search for a specific track, press the direction key forwards or backwards. A single press will advance the disc on
a track.
The CD player has two special functions it can perform:
l Track scan function
l Random play function.
The scan function allows the user to listen to the first few seconds of all the tracks on the disc. The scan function is
accessed by pressing the button on the MID marked SC. An asterix will display next to the SC symbol to denote that
it is switched on. Once on the player will access each track in turn and play the first ten seconds then move on to the
next. To interrupt this and play a selected track the user must press the SC button again.
The Random play function allows the user to play the contents of the CD in a completely random order. This is
achieved by pressing the button on the MID marked RND. Again an asterix will appear next to the RND in the MID to
denote that this function is active. Tracks can be searched for using the direction keys but selection will not be
sequential, it will follow the random order in the units memory. De-selection of the random mode is achieved by
pressing the RND button again.
MID Function Tests
The MID offers an integrated function test for workshop testing purposes. The test menu is called up by
simultaneously pressing the first and the last menu button while switching on the ignition. This menu is generated by
the MID itself, and the tests are carried out by the MID. The display is disabled for the testing period, even in the event
of a display request. The test is also possible without the I/K BUS connected.
The following are offered in the test menu (selection carried out via the MID rocker buttons):
l DISPLAY: Display test
l KEYS: Button functions
l VOLUME: Increment sensor test
l LEDS: for LED function displays.
The test is concluded by switching the ignition off or after a time out of 5 seconds has elapsed after the last button
actuation.
Display Test
The following are activated in succession on a 3 second cycle:
l All characters with all DOTs
l All characters with number symbol pattern
l All characters with "Z" pattern
l All special text labels: LIMIT, LIMITE, MEMO, STOPPUHR, All special text labels together.
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-32 DESCRIPTION AND OPERATION
LED Function Test
The LEDs are activated in succession on a 3 second cycle:
1 Main line light chamber off
2 Menu line light chamber off
3 TELEPHONE LED red
4 TELEPHONE LED yellow
5 TELEPHONE LED green
6 Heating/ventilation symbol LED.
After the end of the test sequence, the test menu appears once again.
Button Function
The principle of the test lies in visual feedback to the pressing of a button. The menu buttons, selection buttons, the
search rocker button and the AUDIO on/off button are tested. The number of the button pressed is displayed in the
main display as a reaction. When calling up the test, the menu line is erased and the character "_" is displayed in the
main line.
Exiting back to the test menu takes place by means of the time out of 5 seconds after the last button actuation or
ignition off.
Increment Sensor Test (Volume)
As in the case of the test for the button function, visual feedback takes place with each sensor increment.
Shown in the main display is a two-character counter beginning with the dual character "_ _" . With each increment
to the right, the value increases by one up to a maximum of 36, which corresponds to one revolution. If rotation is
carried out to the left, the value decreases by one.
The test is concluded by calling up a new test from the test menu or through general exiting of the function test via
the time out or switching the ignition off.
High Line Audio Operation
All of the functions of the High Line/Multi-Function Display are controlled from the Multi-Function Display. Additional
controls are provided by steering wheel mounted switches and (where fitted) voice operated control.
Steering Wheel Switches
Radio Operation
To access the radio functions of the MFD system turn the unit on by pressing the left-hand rotary control, a display
appears on the monitor with the available options of the system. Using the rotary controller highlight the radio option
and press. This will bring up the radio control screen.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-33
Radio Screen
l Name of radio station
l TP station (name of traffic programme station selected in background)
l MFD Waveband selected
l P3 positions the radio station (if programmed into the memory)
l RDS (Radio Data System) is switched on, station names are displayed and the strongest frequency on which the
station can be picked up is searched for automatically
l Date/time display
l Radio screen display (showing radio stations that are available in the area)
l Regional station function switched on.
If the radio is switched on and on-board computer functions appear on the monitor, the "Audio+OBC" function (on-
board computer) is switched on. Switch off the function (see the computer section).
To change the waveband the “AM/FM” button must be pressed. Each time the button is pressed the waveband
changes over as follows:
l FM/FMD = VHF (very high frequency)
l AM = MW (medium wave)/SW (short wave)/LW (long wave).
Manual Station Selection
It is also possible to manually tune onto a radio station by name or frequency. This is achieved as follows.
1 Select the desired waveband
2 Press the selection button to obtain the selection menu
3 Turn right-hand rotary control until "m Manual station choice" is marked
4 Press the direction arrows to tune the radio until the desired station is displayed.
To tune to the next station, press the tune button in the desired direction (up/down) the next available station will be
searched for. You can select in advance whether to jump to the next possible station or the next stored station, this
is achieved by the following process:
1 Press and hold in the “select key” until PRES ON or PRES OFF ("PRES" is short for PRE-SET) appears on the
monitor
2 PRES ON: Jumps to the next memorised station PRES OFF: Jumps to the next station.
Automatic Search
It is also possible to search and sample the available radio stations. With an Automatic search (SCAN) Stations with
a sufficiently strong signal are heard automatically for a short time, one after the other. This can be achieved as
follows:
1 Press the selection button to obtain the selection menu
2 Turn right-hand rotary control until "SCAN Station sample" is highlighted
3 Press the rotary controller to select this option and start the search
4 Pressing the “select” button stops the search at the tuned station.
BBC R2
TMC
30/07/2001
14:10
Monday
BBC R3
BBC R4
Classic
Radio 1
FOX FM Reg0
FOX FM Reg0
BBC Oxfd
HEART FM
>>
BBC R4
92.7 MHz
TP-Station
:
BBC WM
REG
REG
TP
TP
FMD
FMD
RDS
RDS
H4102
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-34 DESCRIPTION AND OPERATION
It is also possible to search manually for stations and has two levels of sensitivity attached to it. These are:
1 Search run for weaker stations
2 Search run for more powerful stations.
If no appropriate stations are found in the search, a second search run is made which includes the weaker stations.
The process for selecting this type of search is as follows:
1 Turn right-hand rotary control until "II Search sensitive" is highlighted
2 Press to confirm your selection
3 Turn the right-hand rotary control until you hear the desired station.
It should be noted that if the inputs are not made within eight seconds, the procedure will have to be repeated.
Traffic Message Channel
The radio tunes itself in the background to the Traffic Message Channel (TMC) station with the strongest signal. This
is turned on in the navigation system. If it is desired to have a particular TP station in the background TMC will have
to be deactivated in the navigation system. If RDS-TMC has been activated in the navigation system, only TP stations
that also broadcast TMC traffic information can be activated in the background.
Programming Pre-set Radio Stations
The MFD can memorise up to 24 radio stations: 6 FM and 18 AM stations. The AM reception band is subdivided into
separate MW, SW and LW memory ranges, to permit greater flexibility in storing stations. The process for tuning in
and storing a radio station to a preset memory is as follows:
1 Select the waveband (FM, MW, SW and LW)
2 Select the station (search for the correct one as described)
3 Hold the desired memory key pressed in until the station is heard again after a brief interruption.
If the chosen location key is already occupied by a stored station, the station last stored is faded up briefly. If the key
is released immediately, the process will be halted and the previously memorised station will not be lost. However if
the key is held in the original tuned radio station will be lost and its place will be taken by the new radio station
selection.
To access a preset station first ensure the waveband is correct (FM, MW, SW and LW) and then press the appropriate
number key (1–6).
Regional Stations
On FM, certain stations may broadcast regional stations either all day or at certain times of day only. If it is desired to
receive these stations, the regional function must be switched on as follows:
1 Press the “info” button
2 Turn right-hand rotary control until "RDS" is highlighted
3 Turn until "Region On/Off" is highlighted
4 Press the rotary controller to activate/deactivate the regional function.
The phrase "REG" appears on the screen. If this function is selected this function and the transmitter switches to a
regional station, this option will automatically be displayed on the monitor for selection.
Traffic Report Stations
It is possible to select a radio station with traffic reports and keep it in the background, so that it interrupts the radio
station being listened to when a traffic report is broadcast. This is achieved as follows:
1 Press the “info” button and hold in until "Selected TP station" is displayed
2 Turn right hand rotary controller until the desired traffic programme station is highlighted
3 Press the right hand rotary controller to confirm your selection.
To cancel a background station:
1 Press the “info” button and hold in until "Selected TP station" is displayed
2 Turn right hand rotary controller until "Delete TP-Stat" is displayed, push to select
3 Press the right hand rotary controller to confirm your selection.
The radio then broadcasts traffic reports even if the station you have selected does not do so. While traffic reports
are being received, TV reception, radio reception, cassette and CD play are interrupted. The speech output of the
navigation system, however, remains active.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-35
To adjust the volume of a traffic report, turn the volume control to the desired level whilst a traffic report is being
broadcast. This volume is then retained for traffic reports even when the volume has been changed for other audio
sources.
Cassette Operation
To insert a cassette the eject button should be pressed, once pressed the front display panel will drop down to reveal
the cassette slot. Once the tape is inserted it will begin to play automatically. If it is required to change from radio to
cassette operation the mode change button should be pressed. The screen displays the Tape 1 or Tape 2, depending
on which side of the tape was being played the last time cassette operation was accessed.
To fast forward or rewind the tape press the required direction key twice. Pressing one of the direction keys will cancel
this operation and return to play mode.
To operate the track search function press the direction key once in the desired direction. The tape will advance until
it reaches the next track where it will then commence playing. It should be noted that this function will only operate if
there is at least a 4 second gap between tracks.
CD Autochanger Operation
The CD autochanger is located in the passenger compartment glove box. The changer is capable of holding 6 CDs
which are loaded into a cartridge.
The CD player function is accessed by pressing the mode button until the display shows the CD screen. The screen
will display the CD number and track number being played. The CD autochanger has several functions:
l Track search
l Random play
l Fast forward/reverse
l Track scan.
Track search is achieved by pressing the direction arrow key as often as required to reach the desired track.
Random play plays all the track on all the CDs in a random order. This is selected by pressing the select key until the
appropriate screen is visible, turning the rotary controller to highlight the Random button and selecting.
Fast forward/reverse is selected by pressing and holding the direction key in the desired direction or by highlighting
the double arrow button in the display using the rotary controller and selecting by pressing the rotary controller.
The track scan function is accessed by turning the rotary controller until 'Track scan' button is highlighted and pressing
the rotary controller to select. Press the track select key starts the search. The player will play the first 10 seconds of
each track until it is stopped at the required track by pressing the track select key.
Television Operation
The Television image is displayed only up to a speed of 3 km/h (approx. 2 mph), the accompanying television audio
can be heard while the car is being driven. Television operation is selected from the menu screen. Once selected the
screen displays the television programme last used or the last used selection. and the following menu screen:
l Programme
l Search
l Autostore
l Set
l Display
l Teletext.
Programme
Selecting programme from the menu allows the user to scroll through the available stored memory locations.
Search
Selecting the search option allows the user to search for a television station and to store that station to a memory
location. This is achieved by selecting the search option and scrolling through the channels with the rotary controller
and pressing the rotary controller to select. This will then bring up the location store option, turn the rotary controller
until the required location is shown and press the rotary controller once to store the station at that memory location.
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-36 DESCRIPTION AND OPERATION
Autostore
Autostore is a convenient method of storing ten television channels to the memory quickly. To achieve this first select
the autostore option from the menu, by turning the right-hand rotary controller. Turn the right-hand rotary controller
until "Autostore" is marked and select to start an automatic station search and store. The first 10 stations are stored
in memory locations 21 – 30.
Set
The set option allows the user to adjust the following television option.
l Contrast
l Brightness
l Colour
l TV format.
To adjust each one turn the right-hand rotary controller to select the option required and press to select. Then use the
rotary controller to adjust the slider up or down on the screen. In the case of the TV format it is possible to change the
country of use. Again using the right-hand rotary controller select the TV format option and select by pressing. Using
the rotary controller scroll through the countries until the required country is found and select by pressing the rotary
controller.
Display
The display menu allows the user to change the screen format to one of the following.
l 16:9 widescreen mode (default setting)
l 4:3 normal television screen size, this will produce black bands down each side of the screen
l Zoom this allows non wide screen format transmissions to be viewed as full screen (without the black bands).
Teletext
The teletext mode allows the user to read teletext pages as on normal television. Using the right-hand rotary controller
select teletext form the menu. Again the right-hand rotary controller scroll to the page number required and press
select to view the page (the page may take a while to load). The zoom option allows the display to be zoomed to make
reading the text easier. If it is required to keep the page viewed rather than let it scroll over to the next page the hold
button can be pressed to hold the current page. Turning the rotary controller releases the page. Selecting the TV
option returns the screen back to the television function.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-37
DESCRIPTION AND OPERATION
Navigation System Component Location
(Except Japan)
1 GPS antenna
2 Multi function display (MFD)
3 Instrument pack
4 Television module
5 Navigation computer
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-38 DESCRIPTION AND OPERATION
Navigation System Control Diagram
(Except Japan)
A = Hardwired connection; C = Diagnostic DS2 bus; K = I bus
M86 5845A
1
A
2
3
4
5
6
7
8
9
10
11
12
13
14
K
C
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-39
1 ABS ECU
2 Diagnostic socket
3 Instrument pack
4 Television module
5 Multi function display
6 Global Positioning System (GPS) antenna
7 Radio module
8 Speakers
9 Digital signal processor (DSP)
10 Power amplifier
11 Microphone
12 Voice recognition unit
13 Navigation computer
14 Light check module
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-40 DESCRIPTION AND OPERATION
Navigation System Component Location
(Japan Only)
1 GPS antenna
2 VICS antenna
3 MFD
4 Instrument pack
5 VICS receiver
6 GPS receiver
7 Navigation computer
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-41
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ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-42 DESCRIPTION AND OPERATION
Navigation System Control Diagram
(Japan Only)
A = Hardwired connection; C = Diagnostic DS2 bus; K = I bus
M86 5846
1
A
2
3
4
5
11
12
15
16
6
7
10
14
13
8
9
K
C
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-43
1 DSC ECU
2 Diagnostic socket
3 Instrument pack
4 Television module
5 Multi function display
6 GPS receiver
7 GPS antenna
8 VICS receiver
9 VICS antenna
10 Speaker
11 DSP
12 Power amplifier
13 Radio module
14 Telephone ECU (JBIT)
15 Navigation computer
16 Light check module
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-44 DESCRIPTION AND OPERATION
New Range Rover Navigation System
Introduction To The Global Positioning System (GPS)
The system used to calculate the current position of the vehicle is called the Global Positioning System (GPS). The
system utilises satellites which are owned by the United States Department of Defence (DoD). A total of 24 satellites
circular orbit the earth every 12 hours at a height of 20,000 km (12500 miles), and between 5 and 11 of these satellites
can be seen from a single point at any given time. The orbits are tilted to the earth's equator by 55 degrees to ensure
coverage of polar regions. Each satellite transmits radio signals to provide information about the satellite position i.e.
latitude, longitude, altitude, almanac data and an accurate time signal generated by an on-board atomic clock. Each
satellite contains four atomic clocks
The vehicle needs to receive data from at least four different satellites to give a three dimensional fix on its current
position.
As the vehicle moves, this information is continually being updated. The computer determines which satellites are
'visible' to the system and their current position and relationship to each other. Using this information the computer
can account for positional deviations of the satellites and compensate to enhance the accuracy of the navigation
system.
The GPS signal is also known as the Precision positioning signal (PPS). This is now the only GPS signal available,
since the Selective positioning signal (a deliberately degraded signal) was turned of on the 2nd May 2000. The
ensures that everyone can now use the higher accuracy available with PPS
SPS predictable accuracy was:
l 100 metres horizontal accuracy
l 156 metres vertical accuracy
l 340 nanoseconds time accuracy.
PPS predictable accuracy is :
l 22 metres horizontal accuracy
l 27.7 metres vertical accuracy
l 200 nanosecond time accuracy.
Each navigation system provides computer generated audible and visual route guidance information to enable the
driver to reach a desired destination. The system allows the driver to choose the desired route using minor or major
roads or motorways and the quickest or shortest route. Directions to hospitals, museums, monuments and hotels are
also available. The computer uses map information stored on a CD-ROM to determine the best route for the journey
and provide the driver with details of directions and approaching junctions.
The system uses almanac data to determine the vehicles position. Almanac data is the current status of the 24
satellites which orbit the earth. The computer determines which satellites are 'visible' to the system and their current
position and relationship to each other. Using this information the computer can account for positional deviations of
the satellites and compensate to enhance the accuracy of the navigation system. The navigation system requires the
almanac data from at least four different satellites to calculate a three dimensional 'fix' on its location. As the vehicle
moves the computer continually up dates this information so that at all times the computer knows the precise location
of the vehicle.
New Range Rover Navigation System
New Range Rover navigation system provides on road navigation capabilities. On road navigation requires a CD
based map to be inserted in the navigation computer. One map disc is supplied with the vehicle, subsequent updated
discs can be obtained from Land Rover dealer-ships at additional cost. Discs are available for different countries and
if road navigation is required whilst travelling abroad map discs will need to be changed for appropriate discs.
Navigation System Components
New Range Rover Satellite navigation system comprises the following components (except Japan):
l Multi-Function Display
l Navigation computer
l GPS (Global Positioning System) antenna.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-45
The Japanese navigation system comprises:
l Multi-Function Display
l Navigation computer
l GPS antenna
l GPS receiver
l VICS (Vehicle Information and Communication Systems) Receiver
l VICS antenna.
Navigation Computer
Navigation Computer
The navigation computer is located in the left hand side of the luggage compartment. The computer is the main
component in the navigation system and receives inputs from the Body Control Unit (BCU) and the GPS antenna. The
navigation computer contains a solid state piezo gyro which measures the motion of the vehicle around its vertical
axis. The gyro operates on the principle known as the Coriolis force. The Coriolis force is the force that appears to
accelerate a body moving away from its rotational axis against the direction of rotation of the axis.
Using the inputs from the BCU, the GPS antenna and the gyro sensor, the computer calculates the vehicle's current
position, direction and speed.
The navigation computer also houses the CD-ROM drive. The drive is used to read map data from country specific
CD's and also to load updated software into the computer. A button, located adjacent to the CD slot, is provided to
eject the CD from the unit. If ignition is on, one press of the button will eject the CD. If the ignition is off, two presses
are required, one to wake up the system and the second to eject the CD.
Previous Range Rover navigation systems used a separate navigation receiver, this version integrates the receiver
within the navigation computer. The GPS receiver receives information from between 1 and 8 satellites at any one
time. This information is received from the GPS antenna. The built in GPS receiver the following functions:
l Calculation of position (i.e. Latitude, longitude and height), direction and speed
l Collection and storage of almanac data
l Real-time clock.
The navigation computer uses non-volatile memory to store settings and configuration information when it is powered
down. This process takes place just before the computer turns off and occurs approximately one minute after all K-
Bus activity has ceased. Once the power down sequence has been completed, the red LED on the front of the unit is
extinguished.
CAUTION: If the unit is disconnected before the LED goes out the computer could fail to complete its data
storage. This will cause the unit to become unusable and it must be replaced.
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-46 DESCRIPTION AND OPERATION
For the Japanese market the navigation computer is a different component. Although it looks identical the unit houses
a DVD drive and the internal receiver is replaced by an external one. The system also has extra components for the
VICS system (a receiver and an antenna). The VICS system receives allows the vehicle to receive information about
traffic conditions from roadside transmitters and adjust the navigation instructions accordingly. The VICS information
is received by both a radio link and an infra red link. For this reason the antenna is located behind the rear view mirror
on the inside of the windscreen.
Navigation Computer Harness Connector C0897 Pin Details
Navigation Computer Harness Connector C0998 Pin Details
Navigation Computer Connector C0899 Pin Details
Pin No. Description Input/Output
1 Reverse gear selected Input
2 to 9 Not used –
10 Road speed Input
11 Not used –
12 Transmit data, navigation and test interface Output
13 Send request to navigation and test interface Input
14 Clear to send, navigation and test interface Output
15 Navigation and test interface ground –
16 Receive data, navigation and test interface Input
Pin No. Description Input/Output
1 Permanent power supply from battery Input
2 Not connected –
3 I bus Input/Output
4 Red video signal Output
5 to 7 Not used –
8 Green video and synchronisation signal Output
9 Navigation audio positive Output
10 Ground –
11 and 12 Not used –
13 Blue video signal Output
14 Not used –
15 Blue video ground Output
16 Not used –
17 Video synchronisation signal Output
18 Navigation audio negative Output
Pin No. Description Input/Output
1 Data signal Output
2 Data signal Input
3 Permanent battery power supply Output
4 Ground for antenna –
5 Red video signal Output
6 Green video signal Output
7 Blue video signal Output
8 I bus Input/Output
9 Auxiliary power supply Input
10 Permanent battery power supply Input
11 Data signal, inverted Output
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-47
VICS Antenna
VICS Receiver
12 Data signal, inverted Input
13 Auxiliary power supply Output
14 Not used –
15 Video signal ground –
16 Synchronisation signal Output
17 Navigation audio positive Output
18 Navigation audio negative Output
19 Ground –
20 Road speed Input
Pin No. Description Input/Output
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-48 DESCRIPTION AND OPERATION
GPS Antenna
GPS Antenna
The GPS antenna is located in the rear spoiler on the upper taildoor of the vehicle. The antenna is connected to the
navigation computer via a single co-axial cable and passes signals received from the GPS satellites to the built in
receiver for processing.
It is possible for the antenna to lose the signals from the satellites in hilly or tree lined areas, built up areas with tall
buildings, multi storey car parks, garages, tunnels, bridges and during heavy rain/thunderstorms. When the signal is
lost, the navigation computer will continue to give guidance using memory mapped data from the CD map until the
signal is restored.
Multi-Function Display
Multi-Function Display
The Multi-Function Display (MFD) is the user interface for the navigation system. The MFD is also the interface for
the radio, cassette, CD changer, trip computer and telephone functions of the audio system along with the auxiliary
heating timer control, DSP functions, television and teletext. The unit comprises a wide screen format LCD monitor
and associated control buttons. The unit houses a cassette mechanism hidden behind the screen which tilts down to
load / eject the cassette.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-49
Multi-Function Display Cassette Slot
The MFD communicates on the I bus with the navigation computer, the CD autochanger (where fitted), the radio unit,
the telephone (where fitted), the instrument pack and the video module. The communication with the instrument pack
is used for diagnostic communication via the diagnostic DS2 bus.
Multi-Function Display Controls
1 Information button
2 Cassette eject button
3 Telephone button
4 Clock/direction button
5 Tone button
6 Search button
7 Menu access button
8 Right hand rotary controller
9 Left hand rotary controller
10 Mode button
11 Wave band change button
12 Pre-set button
13 Pre-set button
14 Pre-set button
Navigation System Operation
The navigation system is operated entirely from the MFD. The following describes the operation of the navigation
system and assumes there is a correct map disc in the computer and that the ignition is in position II.
Entering a Destination
From the main menu screen select the GPS-navigation option using the right hand rotary controller (turn to highlight
press to select).
M86 5754
1
M86 5753
9
10
11
12
13
14
1
2
3
4
5
6
7
8
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-50 DESCRIPTION AND OPERATION
Main Menu
This brings up the input destination screen.
Input Destination
If the name of a country appears on the monitor in white letters, data for more than one country is stored on the map
CD. Using the rotary controller the country can be selected (if desired/possible) in the usual manner.
Once the correct country has been selected the destination city can be selected.
Input Road
Use the rotary controller to select the first letter of the city. The computer will bring up the first city in its database that
has that letter as its first. If this is the correct city use the rotary controller to highlight the enter button to select the
city. If however the city is not correct, select the next letter. This process is repeated until the city name is completed
in full. Once the city name is correct select the enter button and press store to store the destination city.
Next the road has to be input followed by the house number. This is done in exactly the same manner as the city was
input.
Guidance to Destination
Once the complete destination address has been entered, the city, road and house number are displayed on the
monitor; "Dest' guide" is highlighted.
MENU
GPS-navigation
TMC
30.07.2001
14:10
Monday
On-board computer
Telephone
Set
DSP
Television
Code
Monitor off
H4132
Road:
TMC
30.07.2001
14:10
Monday
UNITED KINGDOM
INPUT DESTINATION
ABINGDON Delete
destinatio
n
return
enter
H4133
Road:
TMC
30.07.2001
14:10
Monday
UNITED KINGDOM
INPUT DESTINATION
ABINGDOM Delete
delete
spaceABCDEFGHIJKLMNOPQRSTUVWXYZXZ
destinatio
n
AUSTIN PLACE 81
return
1234567890
Index
enter
H4135
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-51
Destination Guide
Press the right-hand rotary control to start destination guidance. While the navigation computer is calculating the route
to the destination, the distance and direction to the destination as the crow flies are displayed at the top right hand
corner of the screen.
Once the route has been calculated, the destination address that has been entered appears at the top left hand corner
of the screen. The name of the road which the arrow instructs you to turn into is shown below it, together with the
distance to the junction with that road. A change of direction is likewise indicated by the spoken instructions.
The distance to the next turning is shown at the top right hand corner of the screen. An arrow indicates the direction
of the chosen destination as the crow flies. Your current position is shown at the bottom left: hand corner of the screen.
Should the area travelling through not be fully covered by the map CD, the arrow will display the direction in which the
driver should be travelling.
To repeat an audible instruction use the rotary controller to highlight the “instruction” button and press.
Once programmed with a route it is not necessary for the display to stay on the navigation system. The radio, cassette
or CD player can all be used. The navigation display and audible guidance will warn the driver prior to the next
junction/direction change.
Route Display
Selection of the route display option will call up the route display screen. This screen displays a map view of the route
to be driven along with an icon on the route show the vehicles current position on the route.
Navigation System Diagnostics
Information can be accessed through the diagnostic line using TestBook/T4. Information which can be accessed
includes the following:
l Land Rover part number
l Hardware and software version
l Week and year of manufacture
l LCD brightness
l Read error memory/fault codes.
The button status function can be used to determine the correct functioning of the switch-pack. Sticking buttons can
be observed on the TestBook/T4 screen as well as the correct functioning of all the keys as they are pressed.
Road:
TMC
30.07.2001
14:10
Monday
UNITED KINGDOM
INPUT DESTINATION
Delete
destinatio
n
On main route Traffic i
Dest. GuiInformation
GAYDON
H4136
H4206
Route map
300 yd
TMC
30.07.2001
14:10
LEAMINGTON SPA
2.0 mls
Monday
New route
Information
Instruction
Dest. Input
CHURCH ST.
A452, WARWICK
A452
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-52 DESCRIPTION AND OPERATION
Fault codes
Fault codes are stored in the memory of the system ECUs and are accessed using TestBook/T4. The following table
'ECU fault codes' lists the faults that can be stored by the navigation computer memory.
ECU fault codes
Service Mode
To enter service mode on the high line system, select SET on the menu screen and hold the menu button for eight
seconds. This will then display the 'service mode' menu screen.
l On-board monitor
l NAVIGATION / GRAPHIC ELEMENT
l Video module
l GPS
l Sensor check.
On-board Monitor
Selecting the 'On-board monitor' option displays the 'On-board monitor version' screen as follows.
l SW level
l HW level
l DIAG index
l Bus index
l Encoding index
l Supplier.
If version is selected the 'ON BOARD MONITOR VERSION' screen will be displayed as described above.
l Version
l Key function
l Brightness- the screen brightness can be adjusted by selecting this option.
Select the 'Key function' menu by rotating the LH rotary control and depressing it. The 'ON-BOARD MONITOR KEY
FUNCTION' screen will be displayed. This allows each key on the display unit to be checked for operation. The screen
also shows the following information:
l Key, the screen will show FF if no keys are pressed or FEH if several keys are pressed. The KEY box will change
to reflect the button that has been pressed
l OBM increm sensor- The 'OBM increm sensor' box changes its value as the RH rotary control is turned
l Radio increment sensor- The 'OBM increm sensor' box changes its value when the LH (audio) rotary control is
turned.
Navigation / Graphic Element
Selecting the Navigation / graphic element displays the following options:
l SW level
l HW level
l DIAG index
l Bus index
l Encoding index
l Supplier.
Fault code Description
01 Navigation computer error
04 GPS sensor error
05 Temperature error
06 Application software error
07 Display error
08 Audio error
09 CD error
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-53
Video Module
Selecting 'Video module' will give the Video module information as follows:
l SW level
l HW level
l DIAG index
l Bus index
l Encoding index
l Supplier.
GPS
On selecting GPS the following will be displayed:
GPS version information will appear as
l Receiver version
l Receiver software date.
Selecting the functions box allows the selection of,
l GPS version
l GPS status
l GPS tracking info.
Selecting 'GPS status' will display the following information.
l Latitude - displays the current vehicle Latitude
l Longitude - displays the current vehicle Longitude
l Altitude - displays the current vehicle altitude
l Date/time - displays the current date and time
l G-speed/heading - displays the current vehicle speed and heading
l Rec-stat/Pos-Src displays the current receiver status and position source
l COMMERR - this tells us that there is a communication error between the GPS receiver and the navigation
computer
l SEARCH - Denotes that the system is searching for satellites
l TRACK - Denotes that the system is tracking satellites but does not have enough information to determine a
position. It also shows that the system is functioning correctly
l POS This shows that the system is functioning correctly and is able to fix the position of the vehicle
l PDOP (Position Dilation Of Precision), HDOP ( Height Dilation Of Precision) and VDOP (Velocity Dilation Of
Precision). These values tells us about the precision of geometric position. One is the best value whereas a value
of ten would mean there is no GPS positioning possible.
Selecting 'GPS TRACKING INFO' displays the following information.
l Ch PRN S/N-Displays the satellite being tracked on each channel and their signal strength
l Visible satellites- Displays the number of visible satellites
l Almanac- Displays YES or NO to show whether or not the system is receiving Almanac data.
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-54 DESCRIPTION AND OPERATION
Sensor Check
This screen will display information to check that all the input sensors are functioning correctly.
l Wheel sensors - These are used to calculate the vehicle speed
l GPS satellites - Displays the number of satellites visible to the system at that time
l GPS Status - Displays the number of satellites visible to the system and the GPS status There are four
possibilities for the status and they are as follows
l GPS Error - Communication error between the GPS receiver and the navigation computer. This could be a
system failure
l Satellite search - The system is searching for satellites. This may indicate a system failure
l Satellite contact - The system is tracking a number of satellites but does not have enough information to
determine a position
l Position known - As the name suggests the system is tracking a number of satellites and has determined the
vehicle position
l Gyro - The navigation computer incorporates a gyro which determines any changes in vehicle direction. In this
screen it can be seen moving as the vehicle changes direction
l Direction - This sensor determines whether the vehicle is travelling forwards or backwards and will display FWD
or BWD.
Exiting service mode is achieved by pressing the menu button on the control panel which returns the system to the
main TV/Navigation screen.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-55
DESCRIPTION AND OPERATION
Telephone System Component Location
1 Multi band antenna
2 Microphone
3 Multi Function Display (MFD)
4 Multi Information Display (MID)
5 Steering wheel controls
6 Cordless hand-set
7 Eject box
8 Hand-set antenna
9 Telephone control unit
10 Voice recognition ECU
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-56 DESCRIPTION AND OPERATION
Telephone System Control Diagram
A = Hardwired connection; C = DS2 diagnostic bus; K = I bus
M86 5844
A
20
12
18
19
16
17
5
6
7
8
9
15
14
1
2
3
13
4
10
11
K
C
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-57
1 Multi band antenna
2 Cordless hand-set antenna
3 Cordless hand-set
4 Eject box
5 Speaker
6 Power amplifier
7 DSP
8 Radio unit
9 Cassette/radio unit
10 CD/radio unit
11 Mini disc/radio unit
12 Instrument pack
13 Diagnostic socket
14 MFD
15 MID
16 Rotary coupler
17 Steering wheel controls
18 Microphone
19 Speech recognition unit
20 Telephone ECU
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-58 DESCRIPTION AND OPERATION
Telecommunication System
Introduction
New Range Rover has the option to be supplied with a built in hands free telephone system. Both the Multi-Function
Display (MFD) and the Multi Information Display (MID) are capable of supporting telephone operation. The system is
based around a portable GSM phone which utilises a standard SIM card.
Telephone System
The telephone system comprises the following components:
l Eject box
l Cordless handset
l Cordless handset antenna
l Telephone ECU
l Multi band antenna
l Hands free microphone.
Three 'status' LEDs, fitted either on the lower right hand side of the MID or on the upper right hand side of the MFD,
indicate the status of the telephone system as follows:
Eject Box
Eject Box
The eject box is located in the centre arm rest console. It holds the handset and also a SIM card reader. The SIM card
reader requires the use of an adaptor to allow the use of standard small size SIM cards.
When the handset is in the Eject box the hand set battery will be charged if the ambient temperature is between 0 °C
and 40 °C.
To release the hand set from the eject box the eject key located at the front of the box should be depressed. This
raises the hand set approximately 15° out of the rest position. The eject key inscription is illuminated and this
illumination is variable with the use of the instrument dimmer switch.
Lamp Status System Status
Flashing Red Phone not registered on a network
Steady Red Phone operation possible
Steady Yellow Phone logging on to another network
Steady Green Call in progress
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-59
Cordless Handset
The Cordless hand set has a graphic display on which a maximum of 4 lines each with 16 characters can be shown.
In the first line, information concerning the mobile state ("Phone locked; "Connected") or the battery charge state is
displayed. In the second and third lines there are various formats for inputting optional digits. In the fourth line only
the softkey fields are displayed. Either as a symbol or as fixed text. On activating the menu key, the second and third
line of the display is available for menu selections. When menu selection is concluded the display returns to normal.
All texts can be displayed in upper or lower case. This includes both the mobile handset permanent text items (e.g.
menu texts) and texts edited by the user (e.g. names in phone book) The following information is displayed in the
handset switched-on state, however it is not necessarily displayed during menu navigation:
l Permanent display of battery charge state
l Permanent GSM signal strength.
With the batteries fully recharged, the handset can remain on stand-by for approximately 48 hours and has an air time
of at approximately three hours. If the batteries are completely flat or if new batteries have been inserted, full charging
will take approximately six hours. To charge the batteries, place the handset in the eject box. The batteries are also
charged while the car is parked (ignition off).
The handset is connected with the base station in the car by radio link. This link can be switched off for workshop
purposes or where it is a market requirement. When using the handset, ensure that this switch always remains in
position "1" (to the right).
Eject Box Harness Connector C1252 Pin Details
Pin No. Description Input/Output
1 Permanent power supply from battery Input
2Ground –
3 Interior illumination Input
4 Telephone off signal Output
5 SIM card supply Input
6 SIM card data Input
7 to 9 Not used –
10 SIM card reset signal Input
11 Handset charging control signal Input
12 SIM card inserted signal Output
13 Not used –
14 SIM card data Output
15 to 18 Not used –
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-60 DESCRIPTION AND OPERATION
Cordless Handset Antenna
The cordless handset antenna is located in the left hand side of the luggage compartment. This antenna allows the
cordless handset to communicate with the Telephone ECU.
Telephone Control Unit (TCU)
The TCU located in the left hand side of the luggage compartment. The TCU sends and receives signals from the
cordless handset via the handset antenna. The TCU then sends and receives signals to the GSM antenna via a co-
axial cable. If the unit needs replacing, it must be configured using TestBook/T4.
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-61
TCU Harness Connector
TCU Harness Connector C0947 Pin Details
Pin No. Description Input/Output
1 Handset charging control signal Output
2 SIM card data Output
3 to 11 Not used –
12 Auxiliary power supply Input
13 I bus Input/Output
14 to 16 Not used –
17 Audio negative Output
18 Audio positive Output
19 SIM card supply Output
20 SIM card reset signal Output
21 to 23 Not used –
24 Ground –
25 Permanent power supply from battery Input
26 to 28 Not used –
29 Mute signal Output
30 Not used –
31 Permanent power supply from battery Input
32 Permanent power supply from battery Input
33 Ground –
34 Ground –
35 and 36 Not used –
37 SIM card inserted signal Input
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-62 DESCRIPTION AND OPERATION
Multi Band Antenna
The antenna is located in the rear tailgate spoiler and is the same component for most world markets.
38 SIM card data Input
39 to 41 Not used –
42 Ground –
43 Permanent power supply from battery Input
44 to 46 Not used –
47 Amplifier control signal Output
48 Telephone off signal Input
49 to 51 Not used –
52 Microphone negative Input
53 Microphone wiring screen ground –
54 Microphone positive Input
Pin No. Description Input/Output
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-63
Voice Recognition System Control
Introduction
Voice control enables the driver to activate important functions of the car telephone and navigation systems without
needing to operate any controls manually. This allows the driver to concentrate fully on driving the vehicle. Whenever
the driver issues one of the defined voice commands with the system active, the voice control system converts the
command into a control signal for the telephone or navigation system. The system recognises which system the
command is directed at and routes the direction accordingly. The driver is guided through the dialogues by
announcements or questions.
The voice recognition system is only available in the following language variants:
l UK English
l US English
l Italian
l German.
The voice control system understands around 50 pre-defined commands, which need to be given exactly, word for
word. The driver can prompt the system to speak a selection of the most used commands by activating the system
and giving the command HELP.
If it becomes necessary to place an emergency telephone call, it is recommended that the handset, the steering wheel
switches, the multi information display (MID) or multi function display (MFD) is used to dial an emergency number (this
presumes a number for emergency calls is stored in these systems). The reason for using the manual control is that
under stress the drivers normal voice pattern may become disturbed. This will mean that the system may not
recognise the voice commands being issued and cause the emergency telephone call to be delayed.
System Components
The following describes the components within the voice control system.
ECU
The voice recognition ECU is located in the rear loadspace under the navigation computer where fitted. The ECU
communicates with the radio and navigation systems on the I-Bus and hard wired connections.
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-64 DESCRIPTION AND OPERATION
Voice Recognition ECU Harness Connector
Voice Recognition ECU Harness Connector C2136
Pin No. Description Input/Output
1 to 7 Not used –
8 Microphone negative Input
9 Microphone positive Input
10 Microphone negative Output
11 Microphone positive Output
12 Audio negative Output
13 Audio positive Output
14 to 17 Not used –
18 Amplifier control signal Output
19 and 20 Not used –
21 I bus Input/Output
22 Mute signal Output
23 Telephone on signal Input
24 Auxiliary power supply Input
25 Audio negative Input
26 Audio positive Input
M86 5994
C2136
ENTERTAINMENT AND INFORMATION SYSTEMS
DESCRIPTION AND OPERATION 86-8-65
Steering Wheel Switch Pack
The steering wheel switch pack contains several switches for operation of the audio navigation and cruise control.
The voice recognition system is activated using an I-bus telegram. Activation is achieved by pressing and holding the
voice recognition key on the steering wheel switch pack until an acoustic signal is heard.
Microphone
A single microphone is used for hands-free telephone operation and for the voice recognition system. The microphone
has an integrated noise suppression system for hands-free telephone use.
If replaced the microphone must be correctly orientated. This is achieved by ensuring the arrow on the back of the
microphone is facing the front of the vehicle.
Voice Recognition Microphone
Voice Recognition System Operation
To access voice control of the telephone system, press the key on the steering wheel switch pack.
l A brief press the key (for longer than 750 ms) activates the normal telephone functions
l Holding the key pressed in (until the acoustic signal is heard) activates voice control.
A brief acoustic signal and the display "VOICE RECOGNITION" in the instrument pack message centre indicate that
the system is now in the stand-by mode ready to receive voice commands. Any voice command can be interrupted
by saying the word “CANCEL” or by pressing and holding the steering wheel switch until the system responds with
the phrase “CANCEL”.
ENTERTAINMENT AND INFORMATION SYSTEMS
86-8-66 DESCRIPTION AND OPERATION
Making a Phone Call
Once the system is ready to receive voice commands to dial a telephone number the user has to speak clearly.
The system understands single digits from zero to nine. You can choose to say either Zero or Nought. Numbers such
as ten, eleven, twelve, etc. are not recognised. To speed up input, it is a good idea to group together between three
and five digits into a continuous string. However, you can also say each digit individually, or all digits continuously.
Telephone numbers of up to 20 digits are acknowledged. If a longer number is given, the error message “The number
is full” will be issued.
Voice Operation of the Navigation System
To access voice control of the navigation system, press the key on the steering wheel switch pack.
l A brief press the key (for longer than 750 ms) activates the normal telephone functions
l Holding the key pressed in (until the acoustic signal is heard) activates voice control.
Once the system is active the driver has three main options (in navigation mode):
1 Map mode
2 Information on current position or destination
3 Activation of destination guidance.
Map Mode
Once the system is accessed the command “ROUTE MAP” or “MAP”, will bring the map mode up on the MFD.
Once the map mode is accessed it is possible to change the map scale by issuing the command “SCALE ONE
HUNDRED METRE “ to “SCALE ONE HUNDRED KILOMETRE”. Valid scales are as follows:
l 100, 200, 500 metres
l 1, 2, 5, 10, 20, 50, 100, kilometre.
Information on Current Position or Destination
Information on current position or destination is accessed by issuing the command “PETROL STATION AT
CURRENT LOCATION”. This causes all petrol stations in the vicinity of the vehicle to be displayed on the MFD. If a
destination has been entered into the navigation system it is also possible to issue the command “PETROL STATION
AT DESTINATION”. A full list of petrol stations at the destination is then displayed on the MFD. Selection and
guidance to the chosen petrol station is achieved by tuning the rotary controller and selecting in the usual way.
Once the command has been issued the MFD displays petrol stations along the route.
The information displayed is not limited to petrol stations. Information can be displayed on:
l Car parks
l Hotels
l Restaurants.
To access these functions follow the procedure outline previously replacing the petrol station command with the
required function.
Destination Guidance
To access the destination guidance function the driver issues the command “DESTINATION GUIDE” or
“DESTINATION GUIDANCE”. The computer will start to give voice and map guidance to the chosen destination.
Voice Command System Voice Output Message centre Display
Dial (telephone) number Please speak the number SPEAK NUMBER
Zero, eight, nine Zero, eight, nine, continue ? TEL 089
Three, eight, two, four Three, eight, two, four, continue ? TEL 0893824
One, six, eight One, six, eight, continue ? TEL 0893824168
Dial (number) The number is being dialled TEL 0893824168
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-1
DRIVING AIDSDESCRIPTION AND OPERAT ION
Park Distance Control Component
Layout
1 Front park sensor
2 PDC sounder
3 PDC ECU
4 Rear park sensor
5 Parking switch
DRIVING AIDS
86-10-2 DESCRIPTION AND OPERATION
PDC Control Diagram
A = Hardwired connection; C = Diagnostic DS2 bus; D = CAN bus; K = I bus
1 Ignition switch
2 Fuse 6, passenger compartment fusebox
3 Parking switch
4 PDC sounder
5 ABS ECU
6 Instrument pack
7 Instrument pack sounder
8 Diagnostic socket
9 Front ultrasonic sensors
10 Rear ultrasonic sensors
11 PDC ECU
M86 5804A
1
4
6
8
9
9
9
9
10
10
10
10
11
2
A
3
7
5
C
D
K
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-3
Description
General
The Park Distance Control (PDC) provides an audible warning to the driver when any obstacles are in the path of the
vehicle during forward and reverse parking manoeuvres. The system consists of four ultrasonic sensors in each
bumper, an ECU, a sounder and a parking switch. The system also uses the sounder driven by the instrument pack.
At low speed, the PDC ECU uses the ultrasonic sensors to monitor the area around the bumpers, then outputs a
warning on the PDC sounder or the instrument pack sounder if an object is detected within a monitored area. As well
as detecting solid objects such as posts, walls and other vehicles, the system can also detect less solid objects such
as a wire mesh fence. Objects close to the ground may escape detection but, because of their low height, will not foul
the vehicle.
Ultrasonic Sensors
The ultrasonic sensors are transceivers which are installed in inserts in the bumpers. All eight sensors are identical
and keyed to the inserts to ensure correct orientation.
When the system is active, the sensors transmit ultrasonic pulses. Any reflections from the pulses received by the
transmitting and adjacent sensors are then converted to digital format and output to the PDC ECU.
PDC ECU
The PDC ECU is located next to the rear fusebox behind the trim in the RH side of the luggage compartment.
Inputs and Outputs
Three connectors provide the interface between the PDC ECU and the vehicle wiring. The PDC ECU is powered by
an ignition supply from the passenger compartment fusebox. In addition to hardwired connections with the ultrasonic
sensors, PDC sounder and power supply, the PDC ECU communicates with the instrument pack on the I bus. I bus
communication is used for TestBook/T4 diagnostics and for system operation. System operation related I bus
messages include:
I Bus Messages
Message From To
Road speed ABS ECU PDC ECU
Reverse gear status EAT ECU PDC ECU
Trailer status Light check module PDC ECU
Ambient temperature Instrument pack PDC ECU
Instrument pack sounder request PDC ECU Instrument pack
DRIVING AIDS
86-10-4 DESCRIPTION AND OPERATION
PDC ECU Harness Connectors
PDC ECU Harness Connector C0957 Pin Details
Pin No. Description Input/Output
1 Ignition power supply Input
2 PDC sounder +ve Output
3 Not used –
4 I bus Input/Output
5 Not used –
6Ground –
7 PDC switch LED Output
8 PDC sounder –ve Input
9 Instrument pack sounder Output
10 PDC switch Input
11 Instrument pack sounder (rearward travel gong – Japan
only)
Output
12 Not used –
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-5
PDC ECU Harness Connector C0958 Pin Details
PDC ECU Harness Connector C1457 Pin Details
PDC Sounder
The PDC sounder produces the audible warnings with which the PDC ECU informs the driver of system status and
objects detected at the rear of the vehicle. The PDC sounder is installed behind the trim in the RH side of the luggage
compartment, on the underside of the shelf.
The chime produced on the PDC sounder has a lower tone than that produced on the instrument pack sounder (which
is used to warn of objects detected at the front of the vehicle), to enable the driver to differentiate between the two.
Parking Switch
The parking switch is a non latching push switch installed on the centre console for selecting the system on and off.
When pressed, the switch connects a ground to the PDC ECU. An orange LED above the switch indicates when the
PDC system is active. The LED is activated by a power feed from the PDC ECU.
Pin No. Description Input/Output
1 Rear LH inner PDC sensor ground –
2 Rear RH outer PDC sensor ground –
3 Rear LH outer PDC sensor ground –
4 Rear RH inner PDC sensor supply Output
5 Rear LH inner PDC sensor supply Output
6 Rear RH outer PDC sensor supply Output
7 Rear RH inner PDC sensor supply Output
8 Rear RH inner PDC sensor signal Input
9 Rear LH inner PDC sensor signal Input
10 Rear RH outer PDC sensor signal Input
11 Rear LH outer PDC sensor signal Input
12 Rear LH outer PDC sensor supply Output
Pin No. Description Input/Output
1 Front LH inner PDC sensor ground –
2 Front RH outer PDC sensor ground –
3 Front LH outer PDC sensor ground –
4 Front RH inner PDC sensor supply Output
5 Front LH inner PDC sensor supply Output
6 Front RH outer PDC sensor supply Output
7 Front RH inner PDC sensor ground –
8 Front RH inner PDC sensor signal Input
9 Front LH inner PDC sensor signal Input
10 Front RH outer PDC sensor signal Input
11 Front LH outer PDC sensor signal Input
12 Front LH outer PDC sensor supply Output
DRIVING AIDS
86-10-6 DESCRIPTION AND OPERATION
Operation
General
When the ignition switch is in position II and either reverse gear is selected or the parking switch is pressed, both sets
of acoustic sensors are activated. The PDC ECU only activates the system if reverse is selected for more than 1
second, to avoid nuisance audible warnings when the gear selector lever is being moved between Drive and Park.
The rear sensors are disabled when a trailer is connected to the vehicle.
Park Distance Control Detection Areas
A = Intermittent warning tone; B = Continuous warning tone
When it activates the system, the PDC ECU illuminates the indicator LED in the parking switch, switches on the
ultrasonic sensors and generates a single chime on the PDC sounder and the instrument pack sounder to indicate
the system is active. The PDC ECU then processes the distance readings from the ultrasonic sensors to determine if
there are any objects within the detection areas.
If there are no objects in the detection areas, there are no further audible warnings. If an object is detected, repeated
audible warnings are produced on the PDC sounder or the instrument pack sounder as appropriate. The time delay
between the audible warning tones decreases as the distance between the detected object and the vehicle decreases
until, at approximately 250 mm (10 in), the audible warning tone is continuous.
After the initial detection of an object, if there is no decrease in the distance between the object and the vehicle:
l If the object is detected by one of the central acoustic sensors the time delay between audible warning tones
remains constant
l If the object is detected by a corner transducer the audible warning tones stop after approximately 3 seconds.
The audible warning tones are discontinued when the gearbox selector lever is moved out of reverse, but will restart
if the PDC ECU detects a decrease in the distance between the vehicle and an object.
System operation is cancelled when the parking switch is pressed or the ignition is switched off. System operation is
also cancelled if the vehicle travels more than 50 m (164 ft) or forward speed exceeds 19 mph (30 km/h).
700mm (27.5in)
250mm (10in)
600mm (23.5in)
'Y'
'Y'
1500mm (59in)
250mm (10in)
'Y'-'Y'
M86 5805
A
B
600mm (23.5in)
'X'-'X'
'X'
'X'
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-7
The PDC ECU software incorporates routines that compensate for the effect of ice, frost and rain on the acoustic
sensors. Ice compensation occurs if the ambient temperature is less than 6 °C (43 °F).
Diagnostics
The PDC ECU performs self check routines and checks the system wiring for short and open circuits. While the
system is active the PDC ECU also monitors the data from the acoustic sensors.
If a fault is detected, a related fault code is stored in the non volatile memory of the PDC ECU and either the front
sensors, the rear sensors or the complete system is disabled, as appropriate. To advise the driver of the failure, the
PDC ECU flashes the indicator LED at 2 Hz and sounds a continuous warning tone for 3 seconds, in place of the
normal short tone, when the system is activated.
Fault codes can be accessed using TestBook/T4, which communicates with the PDC ECU via the instrument pack
and the I bus.
DRIVING AIDS
86-10-8 DESCRIPTION AND OPERATION
DESCRIPTION AND OPERATION
Tyre Pressure Monitoring Component
Layout
1 Tyre sensor
2 TPM reset switch
3 TPM antenna
4 TPM ECU
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-9
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DRIVING AIDS
86-10-10 DESCRIPTION AND OPERATION
TPM Control Diagram
A = Hardwired connection; B = K bus; C = Diagnostic DS2 bus; F = RF transmission
M86 5807A
1
2
3
5
6
7
8
9
9
9
8
9
10
8
8
A
F
B
9
4
C
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-11
1 Ignition switch
2 Fuse 6, passenger compartment fusebox
3 Fuse 16, passenger compartment fusebox
4 TPM reset switch
5 BCU
6 Instrument pack
7 Diagnostic socket
8 TPM antenna
9 Tyre sensor
10 TPM ECU
DRIVING AIDS
86-10-12 DESCRIPTION AND OPERATION
Description
General
The Tyre Pressure Monitoring (TPM) system continuously monitors tyre pressures so long as vehicle battery power
is available. If a low tyre pressure is detected, the system alerts the driver via the message centre when the ignition
is on. The system monitors the tyre pressure of each road wheel and the full size spare wheel. The tyre pressure of
a space saver spare wheel is not monitored.
The TPM system consists of the following components:
l A reset switch
l A tyre sensor in each monitored wheel
l An antenna in each wheelarch
l An ECU.
The tyre sensors measure the air pressure and temperature in the tyres and transmit the readings in radio signals at
a frequency of 433 MHz. The radio signals are received by the antennas and transferred to the TPM ECU, which
compares the information from the tyre sensors with nominal pressures stored in memory, and alerts the driver if a
tyre pressure decreases from the nominal pressure by more than the permitted limit.
The reset switch is used to initialise the TPM ECU. During initialisation the TPM ECU adopts the current tyre pressures
as the nominal pressures.
TPM Reset Switch
The TPM reset switch is a non latching push switch installed on the centre console below the A/C control panel. While
pressed, the reset switch connects a ground to the TPM ECU.
Tyre Sensor
A tyre sensor is installed on the wheel rim of each monitored wheel, and connected to the tyre inflation valve. The tyre
inflation valve and a Torx bolt secure the tyre sensor to the wheel.
The tyre sensor incorporates a pressure sensor, temperature sensor, signal processor, radio transmitter and a non
serviceable 3.6 V battery. Nominal service life of the battery is seven years. Battery status can be checked using
TestBook/T4.
The electronics of replacement tyre sensors are inactive until they have been subjected to a pressure of 1.5 bar (21.75
lbf/in
2
), i.e. installed on the wheel and the tyre inflated. To conserve power in service, the signal processor adopts
different operating modes depending on the prevailing conditions:
l Normal operating mode, for stable or slow changes of pressure, when the sensing rate is every 3.4 seconds and
transmission rate approximately once every 55 seconds
l Emergency operating mode, adopted if the pressure decreases more than 0.2 bar (3 lbf/in
2
) in 30 seconds, when
both the sensing and transmission rates are once every 0.85 second. Reverts to normal operating mode after
218 seconds
l Deactivated mode, for temperatures in excess of 120 °C (248 °F) (making sensor readings and transmission
unreliable), when sensing and transmission electronics are deactivated and the TYRE CONTROL INACTIVE
warning is displayed. The electronics are re-activated when the temperature decreases to 110 °C (230 °F) for
218 seconds.
Each transmission from a tyre sensor contains:
l A synchronisation byte
l Pressure reading
l Temperature reading
l Identification number
l Remaining life of the battery, in months
l Status information.
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-13
Tyre Sensor Assembly
1 Sensor body
2 Torx bolt
3 Filter
4 Inflation valve
TPM Antenna
A TPM antenna is installed inside each wheel arch, behind the wheelarch liners. 'Twisted pair' wires connect each
TPM antenna to the TPM ECU.
TPM ECU
The TPM ECU is installed below the front passenger seat, in a mounting bracket together with the Body Control Unit
(BCU) and the security system tilt sensor. The TPM ECU incorporates a Radio Frequency (RF) receiver, to decode
the radio signals from the antennas, and system electronics for control and diagnostics.
Power for system operation is provided by a permanent power feed and an ignition switched power feed from fuses
in the passenger compartment fusebox. On a K bus connection with the instrument pack, the TPM ECU can:
l Communicate with the diagnostic socket
l Receive road speed and ambient temperature data from the instrument pack
l Send caution and warning messages to the instrument pack.
A hardwired connection with the BCU allows the TPM ECU to trigger the vehicle alarm if it detects rapid deflation of
a tyre while the vehicle is parked.
DRIVING AIDS
86-10-14 DESCRIPTION AND OPERATION
TPM ECU Harness Connector C1537 Pin Details
Pin No. Description Input/Output
1 I bus Input/Output
2 Not used –
3 TPM switch Input
4 Not used –
5 Front LH TPM antenna
6 Front LH TPM antenna screen –
7 Front RH TPM antenna
8 Rear LH TPM antenna
9 Rear LH TPM antenna screen –
10 Rear RH TPM antenna
11 to 13 Not used –
14 TPM switch Output
15 Battery power supply Input
16 Ground –
17 Rapid tyre deflation signal Output
18 to 20 Not used –
21 Front LH TPM antenna
22 Front RH TPM antenna screen –
23 Front RH TPM antenna
24 Rear LH TPM antenna
25 Rear RH TPM antenna screen –
26 Rear RH TPM antenna
27 to 30 Not used –
31 Ignition power supply Input
32 Not used –
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-15
Operation
Initialisation
Initialisation is required so that the TPM ECU can learn the identity and position of the tyre sensors, and the nominal
pressures of the associated tyres. Initialisation is invoked by pressing and holding the reset switch, with the ignition
switch in position II and the engine off, until the SET TYRE PRESSURE message appears in the instrument pack
message centre (approximately 4 seconds). When the switch is first pressed, a series of asterisks appear in the
message centre to confirm that the TPM ECU has received the switch input. The SET TYRE PRESSURE message
goes off after approximately 16 seconds.
NOTE: On later vehicles the wording of the message may be re-arranged to TYRE PRESSURE SET to reflect that
the message is an acknowledgement and not a command.
Initialisation is required after:
l A tyre pressure has been adjusted
l A wheel has changed position, e.g. swapped axles or the spare installed as a road wheel
l A replacement tyre sensor or TPM ECU has been installed.
WARNING: Without initialisation tyre pressure monitoring is inaccurate and may not be able to detect an
unsafe tyre pressure. Inflating tyres to the recommended pressure for the current vehicle load and driving
conditions remains the responsibility of the driver.
NOTE: Vehicles are built with tyres at storage pressure. At PDI tyres must be inflated to the correct pressure and,
where fitted, the TPM system must be initialised.
After being invoked by the reset switch, initialisation occurs during the subsequent drive cycle(s) when the vehicle is
travelling at more than 2.5 mph (4 km/h). At lower speeds initialisation is suspended, then automatically continued
when the speed goes above 2.5 mph (4 km/h) again. Initialisation is a transparent process that takes from 15 to 30
minutes and is conducted while driving to reduce the possibility of interference from outside RF transmission sources.
There are two phases to the initialisation process: a wheel identification phase and a wheel position phase.
Wheel Identification
Wheel identification takes from 4 to 8 minutes. When the TPM ECU has received more than three transmissions from
the same tyre sensor, it recognises that tyre sensor as belonging to the vehicle. The TPM ECU records up to five tyre
sensor identities and their current pressure and temperature readings. From the pressure and temperature of each
tyre, the TPM ECU calculates a theoretical pressure at 20 °C (68 °F) and uses this as the nominal pressure for
monitoring.
The TPM ECU then begins to monitor the tyres for pressure loss and continues the initialisation process to determine
the wheel position of the individual tyre sensors.
Wheel Position
The wheel position phase takes from 3 to 15 minutes. The signals from each tyre sensor are received by all four
antennas, so by monitoring the strength of the signals received by each antenna the TPM ECU determines the
position of the individual tyre sensors and assigns them a wheel position, including, by inference, the spare wheel tyre
sensor (where fitted).
The TPM ECU confirms the wheel positions from the tyre temperatures. When the vehicle is driven the temperature
of the road wheels changes, while the temperature of the spare wheel remains relatively constant. When it detects a
4 °C (7.2 °F) change in temperature, the TPM ECU confirms a road wheel position for the related tyre sensor. When
it detects a temperature increase of less than 4 °C (7.2 °F) then, provided only one wheel has a temperature increase
of less than 4 °C (7.2 °F), the TPM ECU confirms the related tyre sensor in the spare wheel position. The fifth wheel
can also be confirmed in the spare wheel position by default, after four road wheel positions have been confirmed.
After successful assignment and confirmation of the wheel positions, the TPM ECU checks the nominal tyre pressures
to ensure they are within the following limits:
l The nominal tyre pressures must not be less than 1.7 bar (24.65 lbf/in
2
)
l The nominal tyre pressures of wheels on the same axle must be within 0.4 bar (6 lbf/in
2
) of each other.
DRIVING AIDS
86-10-16 DESCRIPTION AND OPERATION
If the nominal pressures are within the limits, the TPM ECU stores them in memory in place of the previous nominal
pressures. Initialisation is successfully completed and the TPM ECU continues to monitor the current tyre pressures
against the new nominal pressures.
If a new nominal pressure is outside the limits, the TPM ECU aborts the initialisation process and reverts to the
previous nominal pressures for pressure monitoring. The TPM ECU also signals the instrument pack to display the
CHECK TYRE PRESSURE message on the message centre for 40 seconds. While the ignition is on the message is
repeated at 1 minute intervals until a valid initialisation is performed.
Occasionally the system may have difficulty assigning and confirming wheel positions, e.g. due to signal interference,
if a spare wheel is masked by luggage, etc. If the TPM ECU cannot successfully complete the wheel position phase,
it discontinues the initialisation process and reverts to the previous nominal pressures for pressure monitoring. At the
start of the next ignition cycle, the TPM ECU also signals the instrument pack to display the CHECK TYRE
PRESSURE message.
Wheel Confirmation
At the beginning of each drive cycle, if the system is not being initialised the TPM ECU retrieves the stored wheel data
from memory and checks it against the current identification and position of the tyre sensors to determine if the tyre
sensor arrangement has changed without being initialised.
If it detects the same tyre sensors installed in different positions, the TPM ECU assigns and confirms the tyre sensors
to their new wheel positions and retains their existing nominal pressures. At the start of the next ignition cycle, the
TPM ECU signals the instrument pack to display the CHECK TYRE PRESSURE message as a reminder to check
that the tyre pressures are correct for their wheel positions and to initialise the system.
If it detects a new tyre sensor on the vehicle, the TPM ECU signals the instrument pack to activate the TYRE
CONTROL INACTIVE warning while it learns the identity, wheel position and nominal pressure of the new sensor in
a similar manner to the initialisation process. Once the learning process is completed, the TPM ECU signals the
instrument pack to de-activate the TYRE CONTROL INACTIVE warning.
If the confirmation process cannot be completed within 30 minutes, the TPM ECU signals the instrument pack to
activate the TYRE CONTROL INACTIVE warning for the remainder of the drive cycle.
If the TPM ECU detects additional tyre sensors during confirmation, e.g. if additional spare wheels fitted with tyre
sensors are being carried in the vehicle, it disables the system, stores a 'too many wheel sensors' message and
signals the instrument pack to activate the TYRE CONTROL INACTIVE warning.
Pressure Monitoring
The TPM ECU continuously compares the current tyre pressures against the nominal pressures stored in memory.
From each tyre's current pressure and temperature, the TPM ECU calculates the theoretical pressure at 20 °C (68
°F) and compares the result with the tyre's nominal pressure. If the current pressure varies from the nominal pressure
by more than the preset limits, the TPM ECU signals the instrument pack to produce a caution or warning as
appropriate.
Caution
The caution is produced when a tyre pressure is less than the optimum, but still within safe limits for driving, to advise
the driver that tyre pressures should be checked at the next opportunity. The TPM ECU stores the event and outputs
the caution to the instrument pack the next time the ignition is switched on. The caution consists of the CHECK TYRE
PRESSURE message being displayed on the instrument pack message centre. The caution is produced when either
of the following occurs:
l A tyre pressure is between 0.2 and 0.4 bar (3 and 6 lbf/in
2
) below the nominal pressure for 10 signals in
succession
l A tyre temperature is 20 °C (68 °F) or more below the initialisation temperature for approximately 14 days (known
as the 'autumn filter', this alerts the driver to check the tyre pressures to compensate for a seasonal drop in the
mean ambient temperature).
The caution is cancelled when the system is re-initialised. If the system is not re-initialised, the caution is repeated
every 60 seconds while the ignition is on.
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-17
Warning
The warning is produced when a tyre pressure is outside safe limits for driving, to advise the driver that tyre pressures
should be checked immediately. The warning consists of a single chime on the instrument pack sounder and the
TYRE DEFECT message being displayed on the instrument pack message centre. The TPM ECU outputs the
warning immediately if it is detected while the ignition is on, and at the next ignition on if it is detected while the ignition
is off. A warning is produced when one of the following occurs:
l A tyre pressure is 0.4 bar (6 lbf/in
2
) or more below the nominal pressure
l A tyre pressure is 16% or more below the absolute value of the nominal pressure
l A current tyre pressure is less than 1.3 bar (18.85 lbf/in
2
)
l The spare wheel tyre pressure decreases more than 0.2 bar (3 lbf/in
2
) between successive signals (this is an
additional safety feature in case a road wheel has been incorrectly assigned as the spare wheel)
The warning remains on while the ignition is on. The warning is cancelled when the tyre pressure is restored within
limits or the system is re-initialised.
NOTE: The TYRE DEFECT message will be displayed if the ignition is switched on during replacement of a tyre.
Vandal Monitoring
When the vehicle security system is armed, if the TPM ECU detects a sudden loss of pressure, e.g. when a tyre is
slashed or the inflation valve removed, it signals the Body Control Unit (BCU) to trigger the vehicle alarm.
Diagnostics
The TPM ECU performs self check routines and monitors the system wiring, tyre sensors and signal reception for
faults.
If a fault is detected, a related fault code is stored in the non volatile memory of the TPM ECU. To advise the driver
of the failure, the TYRE CONTROL INACTIVE message is displayed on the instrument pack message centre.
Fault codes can be accessed using TestBook/T4, which communicates with the TPM ECU via the instrument pack
and K bus.
DRIVING AIDS
86-10-18 DESCRIPTION AND OPERATION
INSTRUMENTS
DESCRIPTION AND OPERATION 88-1
INSTRUMENTSDESCRIPTION AND OPERATION
Instrument Pack – Front View
RHD UK Td6 specification shown
1 Fuel level gauge
2 Left turn indicator lamp
3 Speedometer
4 Main beam indicator lamp
5 Tachometer
6 Right turn indicator lamp
7 Coolant temperature gauge
8 Supplementary Restraint system (SRS)
warning lamp
9 Anti-lock Brake System (ABS) warning lamp
10 General brake warning/brake assist warning
lamp
11 Seat belt warning lamp
12 Handbrake warning lamp
13 Cruise control active lamp
14 Check control button
15 Low range indicator lamp
16 Gear position indicator
17 External temperature display
18 Message centre display
19 Hill Descent Control (HDC) lamp
20 Trip recorder display
21 Dynamic Stability Control (DSC) lamp
22 Glow plug active lamp (diesel models only)
23 Odometer
24 Service interval indicator
25 Trip reset / Service interval reset button
26 Phototransistor
27 Low oil pressure warning lamp
28 Malfunction Indicator Lamp (MIL)
29 Battery charge indicator
30 Rear fog lamp active lamp
31 Front fog lamp active lamp
32 Low fuel level warning lamp
1/2
1/2
1
/1
1/1
30
30
110
130
130
150
10
90
50
70
2
1 3
4 5
6
7
8
101113
151214
16
1719 18
23
21
2024
25
27
2831
9
26
32 22
30
29
INSTRUMENTS
88-2 DESCRIPTION AND OPERATION
Instrument Pack – Front View – NAS
Only
1 Fuel level gauge
2 Left turn indicator lamp
3 Speedometer
4 Main beam indicator lamp
5 Tachometer
6 Right turn indicator lamp
7 Coolant temperature gauge
8 Supplementary Restraint system (SRS)
warning lamp
9 Anti-lock Brake System (ABS) warning lamp
10 General brake warning/brake assist warning
lamp
11 Seat belt warning lamp
12 Handbrake warning lamp
13 Cruise control active lamp
14 Check control button
15 Low range indicator lamp
16 Gear position indicator
17 External temperature display
18 Message centre display
19 Hill Descent Control (HDC) lamp
20 Trip recorder display
21 Dynamic Stability Control (DSC) lamp
22 Not used
23 Odometer
24 Service interval indicator
25 Trip reset / Service interval reset button
26 Phototransistor
27 Low oil pressure warning lamp
28 Service Engine Soon (MIL) warning lamp
29 Battery charge indicator
30 Rear fog lamp active lamp
31 Front fog lamp active lamp
32 Low fuel level warning lamp
1/2
1/2
1
/1
1/1
30
110
130
130
150
10
90
50
70
2
1 3
4 5
6
7
8
101113
151214
16
1719 18
23
21
2024
25
27
2831
9
26
32 22
30
29
INSTRUMENTS
DESCRIPTION AND OPERATION 88-3
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INSTRUMENTS
88-4 DESCRIPTION AND OPERATION
Instrument Pack – Control Diagram
A = Hardwired; B = K Bus; C = Diagnostic DS2 bus; D = CAN Bus; K = I Bus
M88 0344A
1
2
3
4
5
6
7
8
10
9
11
12
13
14
15
17
18
19
20
21
22
23
24
25
26
A
B
D
16
C
K
INSTRUMENTS
DESCRIPTION AND OPERATION 88-5
1 Fuse - Battery permanent supply
2 Diagnostic socket
3 Anti-lock Brake System (ABS) ECU
4 Hand brake switch
5 Supplementary Restraint System (SRS) DCU
6 Brake fluid level switch
7 Engine coolant level sensor
8 Washer fluid level sensor
9 Light Check Module (LCM)
10 Instrument pack
11 Engine Control Module (ECM)
12 Oil pressure sensor
13 Ambient air temperature sensor
14 Fuel tank level sensor LH
15 Fuel tank level sensor RH
16 Engine Coolant Temperature (ECT) sensor
17 Sounder
18 I Bus interface
19 K Bus interface
20 CAN interface
21 Brake pad wear sensor - Rear RH
22 Brake pad wear sensor - Front LH
23 Body Control Unit (BCU)
24 LH Column stalk switch
25 Fuse - ignition feed
26 Ignition switch
INSTRUMENTS
88-6 DESCRIPTION AND OPERATION
Description
General
The instrument packs fitted to all New Range Rover models are similar and only differ in the following features:
l mph or km/h speedometer
l tachometer maximum rev/min band.
l mph or km/h odometer and trip display
l message centre language display
l ambient temperature display °C or °F.
The instrument pack is a totally electronic device which receives analogue or digital signals via hardwired or bus
systems for instrumentation operation.
The signals are processed by two microprocessors which transpose the data into analogue gauge indications or
warning lamp illumination. The pack is connected to the vehicle electrical system by three connectors which provide
all input and output connections for instrument pack operation.
No internal components of the instrument pack are serviceable, with the only changeable parts being five 1.5W bulbs,
at the rear of the pack, which are used for LCD backlighting illumination.
The instrument pack has two main functions; to provide information to the driver of the vehicle status and to process
and relay digital signals from and to other system controlling ECU's.
The instrument pack features the following displays:
l Tachometer - large analogue display
l Speedometer - large analogue display
l Fuel gauge - small analogue display
l Engine coolant temperature gauge - small analogue display
l Engine service data - LED illuminated
l Gearbox/transfer box status indicator - LED illuminated
l Odometer - LCD
l Trip meter - LCD
l Ambient temperature - LCD
l Message centre - LCD.
The instrument pack also features a number of warning lamps. The warning lamps illuminate in one of four colours
which indicate the level of importance of the warning as follows:
l Red = Warning
l Amber = Caution
l Green = System operative
l Blue = Headlamp main beam operative.
Warning Lamps
The warning lamps are located in two groups at the left and right hand side of the pack. The direction indicators and
main beam warning lamps are located at the top of the display and the glow plug, DSC and HDC warning lamps are
located above the message centre, between the two large analogue gauges.
The warning lamps can be split into two groups; self controlled and externally controlled.
Self controlled lamps are dependant on software logic within the instrument pack for activation. The pack software
controls the lamp check illumination at ignition on and all lamps whose operation is wholly controlled by the pack, the
low fuel level warning lamp for example.
Externally controlled lamps are supplied with a current from another system controlling ECU or triggered by the pack
on receipt of a bus message from another ECU.
Some lamps are activated by an external ECU, but the control logic is retained within the pack. For example, the
direction indicator warning lamps are synchronised and controlled by the LCM, but the lamp illumination logic is
retained within the pack. These lamps are shown in the following table as being self and externally controlled.
INSTRUMENTS
DESCRIPTION AND OPERATION 88-7
The following table shows the available warning lamps and indicates if they are subject to a bulb check illumination
and if they are self controlled or externally controlled.
Analogue Instruments
The analogue instruments are:
l speedometer
l tachometer
l fuel level gauge
l engine coolant temperature gauge.
Speedometer
The speedometer is an electrically driven, analogue instrument for displaying the vehicle speed. The pointer needle
is oil damped to prevent impacts on the vehicle wheels, causing deflection of the pointer needle.
The speedometer is driven by a square wave signal derived from the ABS ECU. The wheel speeds are measured by
sensors reading rotational speed from toothed targets on the hubs. These speeds are passed to the ABS ECU in the
form of pulsed signals. The ABS ECU is programmed that 48 pulses is equal to one revolution of the wheels and this
equates in distance to approximately 2 metres. The actual signal that drives the speedometer is a buffered signal sent
from the left hand rear speed sensor.
Warning Lamp Illumination
Colour
Bulb Check Self controlled
(S)/ Externally
controlled (E)
Gear selector lever 'P' Green No E
Gear selector lever 'R' Green No E
Gear selector lever 'N' Green No E
Gear selector lever 'D' Green No E
Gear selector lever '5' Green No E
Gear selector lever '4' Green No E
Gear selector lever '3' Green No E
Gear selector lever '2' Green No E
Gear selector lever '1' Green No E
Transfer box low range Green No E
Seat belt warning Red No S/E
Brake assist warning Amber Yes E
EBD warning Red Yes E
General brake warning Red Yes S
HDC Green Yes E
Glow plug active Amber No E
Low fuel level Amber Yes S
Left direction indicator Green No S/E
Right direction indicator Green No S/E
Front fog lamps Green No E
Rear fog lamps Green No E
Headlamp main beam Blue No E
Handbrake Red Yes S
Battery charge indicator Red No E
Dynamic stability control Amber Yes * E
MIL / Service engine soon Amber No E
Oil pressure Red No E
ABS Amber Yes * E
SRS Red No E
Cruise control Green No E
* = Bulb check performed by ECU, not instrument pack
INSTRUMENTS
88-8 DESCRIPTION AND OPERATION
This information is passed from the ABS ECU, on a hardwired connection, to the instrument pack and is received by
one of the microprocessors. The microprocessor applies a formula to the signal and calculates a numerical, 16 bit
value for the signal. This signal is then used by the speedometer drive to display the current speed to the driver. A
second digital signal output is also broadcast on the CAN, I and K buses for use by other systems.
To prevent incorrect readings due to spinning wheels, the microprocessor introduces a time delay on the output signal
if the received speed signal increases too quickly. The delay ensures that only the true speed is displayed and
transmitted on the bus systems.
Two versions of the speedometer display are used. One shows the speed in kilometres per hour and the other shows
the speed in miles per hour as the main display and kilometres per hour as a secondary display.
Tachometer
The tachometer is an electrically driven, analogue instrument for displaying the vehicle engine speed. The pointer
needle is oil damped to prevent impacts on the vehicle wheels, causing deflection of the pointer needle.
The tachometer is driven by an engine speed signal transmitted on the CAN from the ECM. The signal is in the form
of a square wave signal of variable frequency derived from the crankshaft position sensor. The signal is received by
one of the microprocessors which processes the signal. The output signal from the microprocessor is then used to
drive the tachometer.
Two versions of the tachometer are used for petrol and diesel engine variants. The petrol engine variants use a display
which has a maximum engine speed reading of 7000 rev/min. The diesel engine variants use a display which has a
maximum engine speed reading of 6000 rev/min.
Fuel Level Gauge
The fuel gauge is an electrically driven, analogue instrument for displaying the fuel tank contents. The pointer needle
is oil damped to prevent impacts on the vehicle wheels, causing deflection of the pointer needle. When the ignition is
off, the pointer returns to the empty position.
The instrument pack is connected to two tank level sensors. One sensor is located in each side of the saddle type fuel
tank and uses a float operated potentiometer for measuring the tank contents. Each tank level sensor is supplied with
a current from the instrument pack. The returned current, via the potentiometer of the sensor, is read by one of the
microprocessors. The reduced current from both sensors is evaluated and converted into a signal to position the fuel
gauge needle at the appropriate level reading. When the microprocessor determines that fuel tank contents have
reached a predetermined level, the low fuel level warning lamp is illuminated and a chime is emitted from the sounder
to alert the driver of the low fuel condition.
The following table shows potentiometer resistance values in relation to fuel tank contents and the fuel gauge display.
The figures are shown as a guide only because an infinite number of left/right sensor resistance values can be
obtained.
Two versions of the fuel level gauge are used. Markets with a kilometres only speedometer use a percentage gauge
reading marked 0 - 100%, with graduations of 0, 25, 50, 75 and max. Markets using miles and kilometres speedometer
readouts use an imperial fraction reading marked 0 - 1, with graduations of 0,
1
/
4
,
1
/
2
,
3
/
4
and 1.
Engine Coolant Temperature Gauge
The engine coolant temperature gauge is an electrically driven, analogue instrument for displaying the engine coolant
temperature to the driver. The pointer needle is oil damped to prevent impacts on the vehicle wheels causing
deflection of the pointer needle. When the ignition is off, the pointer returns to the cold position.
Tank Sensor Potentiometer Resistance
Ω Left/Right
Gauge Needle Pointer
Position
20 / 20 0
146 / 121 25% /
1
/
4
280 / 213 50% /
1
/
2
396 / 323 75% /
3
/
4
500 / 428 100% / 1/1
INSTRUMENTS
DESCRIPTION AND OPERATION 88-9
The instrument pack is connected via two wires to the Engine Coolant Temperature (ECT) sensor. This sensor has a
four pin connector, with the remaining two pins connected to the ECM. The ECT sensor is an NTC sensor located in
the engine coolant flow. The instrument pack outputs a signal voltage to the sensor and measures the returned signal.
The sensor resistance falls as the coolant temperature increases. The instrument pack microprocessor evaluates the
returned signal and converts the information into an output drive to position the temperature gauge needle at the
appropriate position. The engine coolant temperature is available for use by other vehicle systems via the CAN.
+ ENGINE MANAGEMENT SYSTEM – Td6, DESCRIPTION AND OPERATION, Description.
+ ENGINE MANAGEMENT SYSTEM – V8, DESCRIPTION AND OPERATION, Bosch ME 7.2 Engine
Management System.
The following table shows coolant temperature relationship to gauge needle pointer position.
The engine coolant temperature gauge is the same on all pack variants. The gauge display has a blue segment for
low temperatures and a red segment for excessively high temperatures. For normal engine operating temperatures
the gauge needle pointer is positioned centrally in the gauge display zone.
Liquid Crystal Display (LCD)
1 Total distance odometer
2 Trip meter
3 Ambient temperature display
4 Message centre
The instrument pack has four separate LCD's which show the following data:
l Odometer – Displays the total vehicle distance travelled
l Trip meter – Displays the total vehicle distance travelled since last reset
l Ambient temperature – Displays the external ambient temperature in °C or °F
l Message centre – Displays system information to the driver.
The LCD is an integral part of the instrument pack. The LCD comprises black segments on a grey background or
green illuminated when the light switch is on. The LCD is illuminated by backlighting which is provided by five 12V/
1.5W single filament bulbs.
Coolant Temperature Gauge Needle Pointer Position
15.00°C (59.00°F) At beginning of blue segment
50.25°C (122.45°F) At end of blue segment
95.25°C (203.45°F) At centre of display
126.00°C (258.80°F) At centre of red segment
M88 0345
4
1
2
3
INSTRUMENTS
88-10 DESCRIPTION AND OPERATION
The backlighting has manual and automatic brightness control. The manual brightness control is only available when
the lighting switch is on and is operated using the illumination dimmer rheostat on the fascia, adjacent to the lighting
switch. The automatic brightness adjustment is controlled by one of the instrument pack microprocessors and a
phototransistor. The phototransistor is located in the instrument pack, adjacent to the MIL/Service Engine Soon
warning lamp. The phototransistor measures the available ambient light and adjusts the display brightness
accordingly.
Odometer
The odometer displays the total distance which the vehicle has travelled. This is calculated by one of the
microprocessors using the wheel speed signals received from the ABS ECU. The total mileage information is made
available to other systems on the I and K Buses and is only transmitted in kilometres, irrespective of market
configuration.
The odometer display can show distances travelled up 999,999 miles or kilometres. When the ignition is off, pressing
the left hand instrument pack button, will allow the odometer reading to be displayed for 25 seconds.
The total distance is also recorded in the instrument pack EEPROM and RAM. This is recorded after every 2
kilometres travelled and transmitted to the LCM. This data is stored and compared to that of the instrument pack to
protect against illegal alteration of the odometer readings.
Trip meter
The trip meter displays the total distance which the vehicle has travelled since the last trip meter reset, up to 999.9
miles or kilometres. This is calculated by one of the microprocessors using the wheel speed signals from the ABS
ECU and is stored in the instrument pack RAM. The trip meter will restart at zero if the total distance exceeds 999.9
miles or kilometres.
The trip meter LCD also contains a small dot, known as the manipulation point. The manipulation point shows if there
is a total distance travelled or other data discrepancy between the instrument pack and LCM. Refer to 'Redundant
Data' section for further details.
Ambient Temperature
The external ambient air temperature is measured by a sensor located behind the Land Rover badge on the front grill
and is connected directly to the instrument pack.
The ambient temperature sensor is an NTC sensor whose resistance falls as the ambient temperature increases. The
instrument pack outputs a reference current of 5.1V to the sensor. The instrument pack microprocessor evaluates the
returned signal and converts the information into a temperature value and displays the appropriate temperature in the
LCD. The temperature display can be adjusted by TestBook/T4 to be displayed in either Celsius or Fahrenheit,
dependent on market requirements.
The instrument pack continuously transmits the ambient temperature signals on the CAN for use by other systems,
when the ignition is on. When the ignition is off, the instrument pack transmits an ambient temperature message on
the I/K bus, once every 10 minutes, for a duration of 400ms.
The sensor is capable of reading temperatures in the range of -45°C (-49°F) to +56°C (+132.8°F). The instrument
pack LCD will display minimum temperatures to -40°C (-40°F) and maximum temperatures to +50°C (+122°F).
The LCM monitors the temperature signals output on the bus systems. If the temperature falls to 3°C (37.4°F) or
below, the LCM outputs a message signal to instrument pack, when the ignition is on. The message signal is received
by the instrument pack which displays a message, 'EXTERNAL TEMPERATURE', with the recorded temperature
alongside. The instrument pack also emits a single chime from the sounder to alert the driver to the warning message.
The display time of the message is between 6 and 15 seconds, dependant on other displayed messages.
INSTRUMENTS
DESCRIPTION AND OPERATION 88-11
Ambient Temperature Sensor Resistance/Temperature Values
Message Centre
The message centre is located at the bottom of the instrument pack. The message centre comprises an LCD, which
has a 20 character text display. The majority of messages are generated by the LCM which monitors system status
via the bus systems and displays system information messages as appropriate. Other system ECU's are also capable
of generating messages to display system status. Most messages are accompanied by a chime, which is requested
by the ECU generating the message and generated by the instrument pack via the sounder.
A check control button is located between the tachometer and the engine coolant temperature gauge. This button
allows the driver to view system status messages which are current in the instrument pack RAM. Pressing and
releasing the check control button, displays current messages in priority order or, if no messages are present, the
message centre displays 'CHECK CONTROL OK'.
The messages are assigned priorities, depending on the effect on driving safety and driving ability of the vehicle. New
messages are displayed and accompanied by a chime from the sounder. Messages are divided into priority groups
P1, P2 and P3. The priority groups are as follows:
l Priority Group P1
This group includes messages which have a direct affect on the driving ability and safety of the vehicle, “ENGINE
OIL PRESSURE” for example. This message requires an urgent and immediate reaction from the driver in
response to the message. P1 messages are also accompanied by appropriate flashing warning lamp symbols
adjacent to the message centre. If more than one P1 message is present, each message is displayed in turn at
3 second intervals. P1 messages are displayed between the symbols “> <” which are flashing.
l Priority Group P2
This group includes messages which do not directly affect driving ability or safety of the vehicle, “CHECK
NUMPLATE LIGHT” for example. This message must be noted by the driver and the cause rectified as soon as
possible. Each message is indicated once for a maximum of 23 seconds. They can be recalled by pressing the
check control, RH, button on the instrument pack. P2 messages are displayed between the symbols “> <”, which
are permanently illuminated with the message.
l Priority Group P3
This group displays messages which relate to fluid levels, “LOW SCREEN WASH” for example. Depending on
the message, some messages are only displayed at the end of a journey, to avoid irritation to the driver. P3
messages are displayed between the symbols “> <”, which are permanently illuminated with the message.
Two other groups are defined as 'End of Journey Messages' and 'Special Messages S and S1', as follows:
l End of Journey Messages
Messages categorised as 'P1' and 'P2' error messages, are displayed again at the end of the journey. Error
messages do not include messages such as “DOOR OPEN”. Messages in the 'P3' group are displayed after the
'P1' and 'P2' messages. New messages, which only occur at the end of a journey, “LIGHTS ON” for example,
are displayed according to their priority.
l Special Messages S and S1
These messages have the highest priority and cannot be overridden by messages in groups 'P1', 'P2' and 'P3'.
They immediately overwrite any currently displayed messages. If more than one special message is present, the
message with the highest priority has priority, after the current displayed message has been shown for at least
1 second. S and S1 messages are not displayed between any symbols.
Temperature Resistance kΩ
-40°C (-40°F) 168.250
-30°C (-22°F) 88.500
-20°C (-4°F) 48.535
-10°C (+14°F) 27.665
0°C (+32°F) 16.325
+10°C (+50°F) 9.9500
+20°C (+68°F) 6.2450
+30°C (+86°F) 4.0285
+40°C (+104°F) 2.6633
+50°C (+122°F) 1.8015
INSTRUMENTS
88-12 DESCRIPTION AND OPERATION
Most messages, especially S, S1 and P messages are accompanied by a chime from the sounder to alert the driver
to their presence. At the end of a journey, a single chime precedes all end of journey messages.
For 3 minutes after the ignition is switched off, messages can be displayed using the check control RH button on the
instrument pack. If more than one message is present, the button must be pressed again to display the next message.
If no messages are present, 'CHECK CONTROL OK' will be displayed for as long as the button is pressed.
The messages are displayed in a language applicable to the vehicle market configuration and can be changed using
TestBook/T4. The following list shows the possible messages which can be displayed.
Message Centre Messages
PRE-HEATING SLOW DOWN
FASTEN SEAT BELTS SELECT NEUTRAL
TIME 8:59 CHECK BRAKE LIGHT
KEY IN IGNITION LOCK ENGINE FAILSAFE PROG
RELEASE HANDBRAKE TAILGATE OPEN
CHECK BRAKE FLUID CHECK FRONT LIGHT
STOP!ENGINE OILPRESS CHECK REAR LIGHT
COOLANT TEMPERATURE CHECK DIP BEAM LIGHT
HDC TEMP. NOT AVAIL. CHECK SIDE LIGHT
HDC INACTIVE CHECK TAIL LIGHT
NO HDC, SLOW DOWN CHECK FRONT FOGLIGHT
LIGHTS ON CHECK REAR FOG LIGHT
SPEED LIMIT CHECK NUMPLATE LIGHT
FUEL INJECT. SYSTEM CHECK TRAILER LIGHT
AIR SUSP. INACTIVE
+ MAX 60 km/h
(Alternating)
CHECK MAINBEAM LIGHT
TRANSFERBOX NEUTRAL TRANS. FAILSAFE PROG
HEADLIGHT DELAY CHECK BRAKE PADS
TRANSMISS'N OVERHEAT CHECK REVERSE LIGHT
EXTERNAL TEMPERATURE X°C/F LOW SCREEN WASH
APPLY HANDBRAKE CHECK AIR SYSTEM
EEPROM LCMC ACCESS MAXIMUM 40 km/h
DOOR OPEN OFF ROAD MAX 50 km/h
DSC INACTIVE CHECK FUEL TANK CAP
HIGH RANGE TYRECONTROL INACTIVE
LOW RANGE TYRE DEFECT
CHECK COOLANT LEVEL CHECK TYRE PRESSURE
MANUAL MODE TYRE PRESS
SPORT MODE SET TYRE PRESSURE
KEY BATTERY LOW CHECK CONTROL OK
TRAILER MODE
INSTRUMENTS
DESCRIPTION AND OPERATION 88-13
Service Interval Indicator
Service Interval Indicator Display
1 Information field - 'TIME INSPECTION'
2 Information arrow
3 Information field - 'OIL SERVICE'
4 Information field - 'INSPECTION'
The service interval indicator is located adjacent to the LCD and uses the odometer LCD to show distance to next
service and date to next service. The indicator displays 'OIL SERVICE' or 'INSPECTION' to inform the driver of the
type of service due.
The service interval indicator is controlled by one of the microprocessors and software in the instrument pack and the
data stored in the EEPROM. The service interval is calculated on fuel consumption which represents the loads placed
on the engine more accurately than distance travelled. Therefore, a vehicle which is driven aggressively will require
a service earlier than a vehicle which is driven economically.
The service interval data is displayed in the odometer for 5 seconds, every time the ignition is switched on.
Remaining Distance Display
1 Distance display 2 Message centre LCD
When the ignition is switched on, the remaining distance to service is displayed for 5 seconds in the odometer LCD.
Simultaneously, the next service type will also be displayed in the service interval indicator.
A minus sign preceding the remaining distance indicates that the service interval has been exceeded and the distance
by which it is overdue.
1
2
3
4
M88 0346
2
1
INSTRUMENTS
88-14 DESCRIPTION AND OPERATION
Due Date Display
1 Date display 2 Message centre LCD
When the remaining distance is displayed, a second press of the instrument pack, LH button, within the 5 second
display period, illuminates the 'TIME INSPECTION' clock symbol for an additional 5 seconds. The distance to service
information displayed in the odometer LCD changes to the due date of the service by showing the month and year.
A decimal point is positioned between the month and the year. In the above example, the year is 2003 and the month
is December.
If the LH instrument pack button is pressed again, within the 5 second period, the odometer LCD changes to the
distance remaining.
Service Interval Indicator Reset Procedure
The service interval can be reset with the following procedure using the instrument pack buttons. TestBook/T4 can
also be used to reset the service interval indicator by connecting to the diagnostic socket and following the reset
procedure.
NOTE: The distances and dates shown are examples only and not necessarily representative of actual messages
displayed.
Check and Reset Procedure
1 Ensure that the ignition is switched off.
2 Press and hold the LH instrument pack button.
3 With the button held, switch the ignition on to position I (AUX).
4 Continue to hold the LH instrument pack button for a further 5 seconds, until the “SIA RESET” appears.
5 The message centre will display the distance to service status as “RESET SIA: 3600km/mls” and the type of
service (OIL SERVICE or INSPECTION).
6 Check that the reset distance limit has been reached.
a If yes, proceed to step 9.
b If no, proceed to step 7.
7 Press the LH button once. The message centre will display the date to service status as “RESET SIA: 03.12”.
8 Check that the reset date limit has been reached.
a If yes, proceed to step 11.
b If no, proceed to step 10.
9 When the distance reset limit has been reached or exceeded, press and hold the LH button for 5 seconds.
“RESET” flashes in the message centre five times.
a If the LH button is not pressed again before the fifth flash of “RESET”, the reset will not be performed. The
message centre will display “END SIA: 3600 km/miles” for 5 seconds and the display will change to the
service date “RESET SIA: 12.03”.
b If the LH button is pressed before the fifth flash of “RESET”, the service distance will be reset. The message
centre will display the new service distance “END SIA: 25000 km/miles” for 5 seconds. The service date will
then be displayed.
M88 0347
1
2
INSTRUMENTS
DESCRIPTION AND OPERATION 88-15
10 Press the LH button once. The message centre will display “END SIA” for 2 seconds. This ends the service
interval check and reset.
11 When the date reset limit has been reached or exceeded, press and hold the LH button for 5 seconds. “RESET”
flashes in the message centre five times.
a If the LH button is not pressed again before the fifth flash of “RESET”, the reset will not be performed. The
message centre will display “END SIA: 03.12” for 5 seconds. “END SIA” will be displayed for a further 2
seconds and the service interval and check will be ended.
b If the LH button is pressed before the fifth flash of “RESET”, the service date will be reset. The message
centre will display the new service date “END SIA: 04.12” for 5 seconds. “END SIA” will be displayed for a
further 2 seconds and the service interval and check will be ended.
The service interval indicator system can only be reset again after 2
1
/
2
gallons (10 litres) of fuel has been recorded as
used by the instrument pack.
Gear Position Display
The gear position display and the low range lamp are controlled by the EAT ECU and the transfer box ECU
respectively. The gear position is illuminated in response to CAN messages from the EAT ECU and the low range
lamp is illuminated on receipt of a CAN message from the transfer box ECU.
The instrument pack has no control over the gear position display, but monitors the controlling CAN messages. If the
instrument pack detects ten incorrect CAN messages, “TRANS. FAILSAFE PROG” is illuminated in the message
centre. If a correct CAN message is received when the ignition is next switched on to position II, the error is erased
and the message removed. If 'Sport' or 'Manual' modes are selected, the instrument pack detects the CAN message
for these selections and displays the applicable message in the message centre.
On-Board Computer
The instrument pack contains software to enable the operation of an on-board computer. The on-board computer
functions can be displayed in the instrument pack message centre, on a Multi-Information Display (MID) or a Multi-
Function Display (MFD), depending on vehicle specification.
The following on-board computer functions are available:
l Time of day
l Date
l Reminder signal (MEMO)
l Ambient temperature (only displayed in the instrument pack LCD and the MFD)
l Average speed
l Anticipated fuel tank range
l Input of distance between journey start and end points (only on MID and MFD) (DISTANCE)
l Anticipated arrival time (ARRIVAL)
l Average fuel consumption (CONSUMPTION 1 & 2)
l Speed warning (LIMIT)
l Stop watch (TIMER) or switching points for park heating/park ventilation (TIME 1 & 2)
l Anti-theft protection (CODE).
The on-board computer functions can be displayed in the instrument pack alone or in the MID/MFD and the instrument
pack simultaneously.
INSTRUMENTS
88-16 DESCRIPTION AND OPERATION
Computer Controls – MID
1 Multi Information Display (MID)
2 Information button
3 Column stalk information button
M88 0353
1
2
3
INSTRUMENTS
DESCRIPTION AND OPERATION 88-17
Computer Controls – MFD
1 Multi Function Display (MFD)
2 On-board computer menu selection
3 Column stalk information button
The on-board computer functions are selected in the MID by pressing the 'i' button for on-board computer functions
or the clock symbol for clock timer functions. On the MFD, the on-board computer functions are selected from a menu
on the LCD or by pressing the clock symbol for clock timer functions. The computer functions can be selected in the
message centre by pressing the 'i' button on the LH column stalk switch.
The instrument pack message centre shows all the possible computer function messages in a scrolling display. The
function displays can be scrolled through using the on-board computer button (i) on the LH column stalk switch. The
column stalk button allows the resetting of certain functions in conjunction with the MID/MFD, and also the order in
which the function displays are scrolled through. Three functions cannot be accessed using the column stalk button,
they are; CODE, MEMO, EXTERNAL AIR TEMPERATURE and HEAT ON/OFF AIR ON/OFF. These functions are
only available using the MID/MFD.
TMC
TMC
30/07/2001
30/07/2001
14:10
14:10
1
3
M88 0354
MENU
GPS-navigation
TMC
30/07/2001
14:10
Monday
On-board computer
Telephone
Set
DSP
Television
Code
Monitor off
2
INSTRUMENTS
88-18 DESCRIPTION AND OPERATION
When the on-board computer is being accessed via the MID/MFD, these units communicate with the instrument pack
message centre to display the function information in the display in the MID/MFD only. The MID/MFD also allow for
the resetting and programming of certain on-board computer functions, such as the clock, date, speed limit and stop
watch.
The on-board computer system of the instrument pack supplies the MID/MFD with data and commands on the I Bus.
Some computer functions require an exchange of data between the Automatic Temperature Control (ATC) ECU and
the Body Control Unit (BCU) which is carried out on the K Bus.
Operation of the buttons on the MID or selections on the LCD screen of the MFD are passed to the instrument pack
software for calculation of the text and numerical values to be displayed. The MID/MFD are purely a user interface
with regard to the on-board computer, with the instrument pack being the controlling component.
The MFD has one exception to this. Using data supplied by the instrument pack, the MFD self generates the text
messages which appear on the LCD screen.
Security Code
The security code function prevents unauthorised persons from starting the engine. This function is controlled from
the MID/MFD. The driver can select and enter a code, without which subsequent starting of the engine is prevented.
This function can be used if the vehicle is to left unattended for a long period of time, i.e. airport car park. Each time
the code is activated, it is only valid until the next time the engine is started. If the code is not available or forgotten,
emergency deactivation is possible.
The CODE is a four digit number which can be entered with the ignition at position I (AUX). If the vehicle is parked
with the code armed, starting of the engine is inhibited until the correct code is entered to disarm the alarm. If the
incorrect code is entered, the alarm horn is activated and the immobilisation ECU prevents starting. This is performed
by messages sent on the K bus to the BCU. The BCU electrically controls the alarm horn and the immobilisation ECU
functions.
The code can be selected on the MID and activated as follows:
Code Activation
l Make sure the ignition is in position I. Press the i key on the MID panel.
l Press the left side of the CODE SET key.
l CODE - - - - is displayed in the main display. Enter the code using the number keys. If the code is incorrectly
input, press the left side of the CLR SET button and re-enter the code.
l Press the right side of the CODE SET button to memorise the input and turn the ignition off.
Code De-activation
l When the ignition is moved to position II, the MID display prompts for the code.
l Using the numbered key buttons, enter the correct code. Once entered, press the right side of the CODE SET
button. If correctly entered the time display will appear and the engine will start.
l If the code is incorrectly entered three times or three attempts to start the engine are performed, the BBUS will
sound for 30 seconds.
The code can be selected on the MFD and activated as follows:
Code Activation
l Select CODE from the main menu.
l Enter the code using the rotary control. Turn the rotary control until the required number appears and press to
confirm. Enter the remaining numbers in the same way. If the code is incorrectly input, select CHANGE and
repeat the input procedure.
l Once the code is entered, it is activated by turning the ignition off.
Code De-activation
l When the ignition is moved to position II, the MFD display prompts for the code.
l Enter the code using the rotary control. Once the code is entered, select DEACTIVATE. If the code is incorrectly
input, select CHANGE and repeat the code input.
INSTRUMENTS
DESCRIPTION AND OPERATION 88-19
Emergency De-activation
l Disconnect the vehicle battery. This will cause the alarm to sound. Wait for a period of more than 5 minutes and
re-connect the battery.
l Turn the ignition to position I. The display will show a count down for 10 minutes. Once the 10 minutes has
expired, the engine can be started. If during the 10 minute period, the code becomes available, it can be input
after pressing the CODE button.
On-Board Computer Functions with Column Stalk Switch
Pressing the on-board computer button (i) on the LH column stalk, displays the first computer function in the
sequence. With each subsequent press of the button, the next function is displayed. The sequence of displayed
functions can be programmed by the driver and can be scrolled through continuously to reach the desired function
display.
When all the functions have been scrolled through once, the message centre appears blank, signifying the end of the
function display. When the on-board computer function display is subsequently requested, the message centre will
display the first function in the sequence. If the function display is interrupted by a system message from the LCM,
when the column stalk button is pressed or the check control button is pressed, the last displayed function will
reappear in the message centre.
The on-board computer function will only be displayed if the LCM releases the message centre for function display.
This will only occur if the LCM is not displaying any high priority messages at the time. The LCM registers the request
for on-board computer function display and, if there are no messages or the displayed message is of a low priority,
the on-board computer function is permitted use of the LCD message centre.
The following list shows the possible on-board computer functions and their standard sequence of display. This order
will be reinstated after a system reset.
l CLOCK
l CONSUMPTION 1
l CONSUMPTION 2
l RANGE
l LIMIT
l DISTANCE
l ARRIVAL
l SPEED
l DATE
l TIME 1 (only with park heating and/or park ventilation)
l TIME 2 (only with park heating and/or park ventilation)
l TIMER.
The following functions cannot be called up using the steering column button. These functions can only be selected
with the MID or MFD.
l HEAT ON/OFF (heating on/off)
l AIR ON/OFF (ventilation output on/off)
l OUTSIDE TEMPERATURE
l CODE.
The sequence of function display is stored in the instrument pack RAM. This sequence can be changed and
programmed by the driver using the MID/MFD, with the new sequence also stored in the RAM. The new sequence
can be programmed as follows:
INSTRUMENTS
88-20 DESCRIPTION AND OPERATION
MFD Programming
MFD 'REMOTE CONTROL' Screen
1 Ensure that the ignition switch is in position I (AUX) or position II.
2 Press and hold the column stalk 'i' button for 3 seconds. 'REMOTE CONTROL' screen is displayed in the MFD
with all computer functions shown. Simultaneously, 'PROG' is displayed in the message centre.
3 To set the sequence, first deselect all functions using the RH control on the MFD panel. Select the function and
press the RH control to deselect that function. When deselected, the selection text will change colour.
4 Using the RH control, navigate to the first required computer function and press the RH control to select. When
selected, the selection text will change colour.
5 Continue selecting functions in the required order as required. If no functions are selected, there will be no
response from the 'i' button when pressed. All or just one function can be selected for display.
6 When desired selections are made, navigate to the 'memorise' function and press the RH control. The selected
functions are stored in their selected order in the instrument pack RAM. The instrument message centre then
displays the first selected function.
MID Programming
MID 'PROG 1' Display
1 Ensure that the ignition switch is in position I (AUX) or position II.
2 Press and hold the 'i' button for 3 seconds. 'PROG 1' appears in the MID with all computer functions assigned
to the keys.
M88 0351
M88 0352
PROG 1
RANGE
SPEED LIMIT
DIST ARRCONSUM1
SET
INSTRUMENTS
DESCRIPTION AND OPERATION 88-21
3 To set the sequence, select the required functions in order required. If no functions are selected and the 'SET'
button is pressed, all computer functions are selected and displayed in their standard sequence.
4 When the selections have been made, press the 'SET' button. The selected functions are stored in their selected
order in the instrument pack RAM. The instrument pack message centre displays the first selected function.
Bus Systems
The instrument pack has two controlling microprocessors which process software information and control input and
output data for the instrument pack and other systems. The processors communicate with other systems on the
vehicle via four interfaces: I Bus, K Bus, CAN and diagnostic DS2 Bus. An 8 Kbyte, non-volatile memory (EEPROM)
is provided for the storage of vehicle and instrument data (eg; mileage reading, service interval status).
The instrument pack also features a self diagnostic feature and on-board diagnostics via communication with
TestBook/T4.
Inputs are received as either analogue signals via conventional hardwired connections or as digital signals via multi-
channel connections with the bus systems. These signals are filtered and evaluated by the processors and the data
converted into actuation of the analogue gauges and indicator/warning lamps. The processors also function as a
gateway for the bus systems, processing data from one system and passing it to another.
The instrument pack receives and transmits data on five bus systems as follows:
Redundant Data Storage
In the event of a new instrument pack having to be installed, certain information needs to be maintained to prevent
data loss. This information is transferred continuously from the instrument pack on the I bus and is received and held
in an EEPROM in the LCM. The data is also stored, along with other vehicle specification data, in the immobilisation
ECU.
The data stored is as follows:
l Vehicle Identification Number (VIN)
l Total distance travelled
l Service interval fuel volume and type of last service
l Service interval clock.
When a new instrument pack is installed, the LCM will update the instrument pack EEPROM with the stored data
providing the following parameters are met:
l The VIN in the instrument pack and the LCM match
l The total distance reading in the instrument pack EEPROM is less than 158 miles (255 km)
l The total distance reading in the LCM EEPROM is less than 999,900 miles or kilometres or equal to or greater
than 0 miles or kilometres
l The total distance recorded in the instrument pack EEPROM is less than the distance travelled stored in the LCM
EEPROM.
Vehicle coding data, such as engine type, market, etc., is stored in the immobilisation ECU and retrieved by TestBook/
T4 and used to update the new instrument pack.
If the VIN in the instrument pack is set to 0, only service interval data is passed from the LCM EEPROM to the
instrument pack RAM, it is not stored in the instrument pack EEPROM. The total distance displayed in the odometer
LCD is frozen at the value stored in the instrument pack EEPROM.
If any of the stored data in the LCM EEPROM conflicts with the data within the instrument pack, a lamp, known as a
manipulation point, is illuminated in the pack. The manipulation point is located in the trip meter LCD, below the 'Miles'
text or next to the 'km' text.
Bus System Single/Dual Line Transmission/Baud Rate (Bd)
I Bus 1 9,600 Bd
K Bus 1 9,600 Bd
CAN 2 500.0 kBd
DS2 Bus 1 9,600 Bd
K line 1 10,400 Bd
INSTRUMENTS
88-22 DESCRIPTION AND OPERATION
The following conflicts will illuminate the manipulation point:
l The VIN transferred from the LCM on the I Bus to instrument pack is 0
l The VIN in the instrument pack is 0
l The VIN in the LCM is different to the VIN in the instrument pack
l A default value in the EEPROM is used until a CAN index message is sent when the ignition is switched on.
If the EEPROM is in an unlocked (unprotected) condition, the manipulation point will flash, irrespective of whether or
not the stored data matches or conflicts.
CAUTION: When a new instrument pack is to be installed, TestBook/T4 must be connected to vehicle and the
instrument pack renewal procedure followed to replace the pack. This will ensure that vehicle coding data is
correctly installed in the new instrument pack. TestBook/T4 will also record the current service interval data
and restore the settings to the new instrument pack.
Instrument Pack Harness Connectors
INSTRUMENTS
DESCRIPTION AND OPERATION 88-23
Instrument Pack Harness Connector C0230 Pin Details
Instrument Pack Harness Connector C0233 Pin Details
Instrument Pack Harness Connector C0234 Pin Details
Pin No. Description Input/Output
1Ground –
2 Not used –
3 Alternator warning lamp Input
4 Oil pressure switch Input
5 Handbrake switch Input
6 Not used –
7 Battery power supply Input
8 Illumination dimmer voltage Input
9 to 12 Not used –
13 SRS warning lamp Input
14 Not used –
15 ABS warning lamp Input
16 Not used –
17 Ignition power supply Input
18 Not used –
Pin No. Description Input/Output
1 Diagnostic DS2 bus Input/Output
2 Not used –
3 Road speed (where fitted) Output
4 to 6 Not used –
7 K bus Input/Output
8 I bus Input/Output
9Ground –
10 Ground –
11 Instrument pack sounder gong 3 Output
12 Auxiliary power supply Input
13 Not used –
14 Engine cranking signal Input
15 Battery power supply Input
16 Ignition power supply Input
17 Instrument pack sounder gong 2 Output
18 Instrument pack sounder gong 1 Output
Pin No. Description Input/Output
1 Road speed Input
2 and 3 Not used –
4 Brake pad wear sensors Input
5 On-board computer switch on LH column stalk Input
6 Not used –
7 Fuel level sensor 1 signal Input
8 CAN bus high Input/Output
9 CAN bus low Input/Output
10 and 11 Not used –
12 Fuel level sensor 1 ground Output
INSTRUMENTS
88-24 DESCRIPTION AND OPERATION
Diagnostics
The instrument pack provides an interface (gateway) for data transfer between TestBook/T4 and the vehicle ECU's.
Individual ECU's subject their functional capabilities to self diagnostic checks. Any irregularities or malfunctions are
stored in the ECU error memory.
The error memories can be interrogated by TestBook/T4 to establish and diagnose the cause of the error messages.
The service interval indicator can be interrogated and reset using TestBook/T4, as an alternative to the instrument
pack reset procedure.
The instrument pack RAM can be reset with TestBook/T4 or using the instrument pack test No. 21 (see following
section). When this procedure is performed, all values stored in the RAM will be erased. Displayed values to the driver,
such as trip meter reading and on-board computer sequence and values, will be erased and resume their default
values or are reset to values of zero.
The instrument pack also performs a self diagnostic routine to check its function and monitoring of related
components. Detected errors are written to the RAM initially and then transferred to the EEPROM when the ignition
is switched off. The EEPROM will only store the five most recent errors. If five errors are stored, only further errors of
the bus systems or instrument pack EEPROM errors will be memorised in their order of occurrence. Errors already
present will be over written. Error messages can be retrieved and diagnosed with TestBook/T4. When the instrument
pack is reset, errors stored in the EEPROM are transferred to the RAM and then erased.
Instrument Pack Test
The instrument pack has a test function to assist with testing, checking and trouble shooting if a repair is required.
Test functions are only displayed in the instrument pack LCD.
There are two methods of entering the test mode:
l The ignition switch must be position I (AUX) or II (IGN) and no messages must be displayed in the LCD. Press
and hold the check control button on the instrument pack for not less than 5 seconds.
l Press and hold the check control button and switch the ignition on to position I (AUX).
When test mode is entered, 'TEST-NR.: 01' appears in the message centre.
13 Not used –
14 Ambient air temperature sensor Input
15 Not used –
16 Fuel level sensor 2 ground Output
17 Not used –
18 ECT sensor ground Output
19 ECT sensor Input
20 Brake pad wear sensors ground Output
21 Not used –
22 Ambient air temperature sensor ground Output
23 Fuel level sensor 2 signal Input
24 Not used –
25 Reverse gear signal Input
26 Not used –
Pin No. Description Input/Output
INSTRUMENTS
DESCRIPTION AND OPERATION 88-25
There are 21 test and reset functions available as shown in the following table:
Pressing the check control button moves the display to the next function in the sequence. When a selected function
is reached, pressing the trip reset button enters the test function details.
All test functions, with the exception of tests No's. 1 and 2, are locked after the instrument pack is reset and must be
unlocked using test No. 19. This locking feature is intended to make instrument pack test functions difficult for
unauthorised persons to access. Refer to function test No. 19 for further details.
Once in the test function, scrolling through the tests sequentially is performed by pressing the check control button on
the instrument pack. When a locked test function is encountered, pressing the trip reset button displays test No. 19
LOCK : ON to allow quick unlocking of the function.
In all markets, the text displayed in the message centre for the test functions is in German only.
The instrument pack test can be exited by turning the ignition off or by holding the check control button depressed for
more than 2.5 seconds.
Test Function No.1 – Instrument Pack Identification
l Test function 1 is not locked and can be accessed immediately. Pressing the trip reset button scrolls through the
following individual information relating to instrument pack identification.
l 'FGNSTNR: AB12345' – Vehicle Identification Number (VIN).
l 'K: 4571' – Speedometer K Index (displayed in pulses per km or mile).
l 'BMWTNR: 8373541' – Instrument pack identification number.
l 'CI: 10 DI: 03 BI: 07' – Coding, diagnostics and bus index reference numbers.
l 'DAT: 47/01:' – Date of manufacture week/year.
l 'HW: 03 SW: 500/500' – Hardware/Software numbers.
l 'ZYL: 6 M:3 S: 425' – Engine data (cylinders, engine factor, fuel supply system slope).
l 'CAN: 01 AEND:23' – CAN and change index.
Test Number Function Description
01 Instrument pack identification
02 System test
03 Service interval indicator data
04 Momentary fuel consumption values - l/100km and l/hour
05 Range consumption and range momentary value
06 Tank content values and display value
07 Momentary values for engine coolant temperature, engine speed and ambient
temperature
08 Momentary values for effective and displayed speed in km/h
09 Battery voltage supply to instrument pack display in volts
10 Read country code
11 Read units display for on-board computer, clock and ambient temperature
12 Average speed for arrival time calculation and momentary arrival value
13 Activation of the chime signals
14 Read self diagnostic error bytes
15 Display of input/output port status
16 Momentary value for engine oil temperature in °C
17 Minute counter for last radio controlled clock reception
18 Dimming parameters
19 Locking and unlocking of test functions
20 Entry of a correction factor for fuel consumption
21 Instrument pack reset
INSTRUMENTS
88-26 DESCRIPTION AND OPERATION
Test Function No. 2 – System Test
l Test function 2 is not locked and can accessed immediately. After selection the instrument pack automatically
activates all displays and analogue gauges. This test will only be performed with the ignition in positions I or II
and the engine not running.
l The backlighting of all LCD's are activated.
l All segments for the odometer, trip meter, ambient temperature and service interval indicator are illuminated.
l All warning lamps are illuminated.
l A pixel test of the message centre is alternately performed to display a 'chess board' pattern. The pixels are
alternately illuminated at intervals of 1.25 seconds. The trip meter display alternates between km and miles
and the ambient temperature alternates between °F and °C.
l The general brake warning lamp alternates between an amber and red output.
l All analogue gauges are activated and travel from the left stop to the right stop and back to the left stop.
l When all gauges have returned to their left stop all displays remain illuminated. A second activation of the
analogue gauges follows, but this time the needle pointers stop before the right stop position. During this
gauge cycle, the instrument pack performs self diagnostics on the gauge operation and records fault data if
necessary. This diagnostic check of the gauges is only performed during test function 2 and the data can be
retrieved using TestBook/T4.
l When the second gauge cycle is complete, normal instrument pack display is resumed.
Test Function No. 3 – Service Interval Indicator Data
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
is displayed and can be scrolled through using the trip reset button.
l 'SI-L: 1250' – SI litres used since the last service interval reset.
l SI DAYS: 325' – SI time counter since last service interval reset.
Test Function No. 4 – Momentary Fuel Consumption Values
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
is displayed and can be scrolled through using the trip reset button.
l 'VBR: 14.3 L/100 KM – momentary consumption in l/100 km for calculation of consumption values.
l VBR: 20.3 L/H – momentary consumption in litres per hour for consumption assessments when the vehicle
is stationary with the engine running.
l The consumption values are calculated from PWM injector signals which correspond to the injected fuel volume.
Test Function No. 5 – Range Consumption and Range Momentary Value
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
is displayed and can be scrolled through using the trip reset button.
The value can be displayed in litres/100km or in MPG, dependant on market programming.
l 'RW-VBR: 12.7 L/100KM' – average fuel consumption.
l 'RW: 3238 KM' – range with remaining fuel tank volume.
l The internal fuel range consumption value displayed in the on-board computer is calculated using the figures for
average tank contents and the distance travelled since the last reset. The fuel range value displayed is calculated
using the same figures to show the available range with the remaining fuel in the tank.
Test Function No. 6 – Tank Content Values and Display Value
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button. The first display line shows the tank content from the left and
right fuel tank level sensors and the overall tank content. The second display line shows the average overall tank
content and the value after 'PHASE' relates to the procedure used to calculate the content value.
l 'TNK: 29.5/34.2/63.7L' – this shows content in left half of tank / content in right half of tank / momentary overall
tank content.
l 'TNKANZ: 60.2L PHASE1' – average tank content and calculation method. The PHASE shows the calculation
method as defined below.
l PHASE1 = Normal calculation procedure using both sensors with no errors.
l PHASE2 = In the case of a tank level sensor failure, the calculation is performed using the injector PWM
signal available on the CAN.
l PHASE3 = If a sensor failure has occurred and the injector PWM signal is not available, the fuel level
gauge will read empty and the low fuel warning lamp will be illuminated.
INSTRUMENTS
DESCRIPTION AND OPERATION 88-27
Test Function No. 7 – Momentary Values for Engine Coolant Temperature, Engine Speed and Ambient
Temperature
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button.
l 'KTMP: 105°C' – This shows the engine coolant temperature. If the ignition is in position II the temperature
signal is passed on the CAN to the instrument pack. If the ignition is in position I, the temperature signal is
read from the analogue input from the engine coolant temperature sensor to the instrument pack.
l 'N: 248/0 U/min' – This shows the momentary engine speed received on the CAN from the ECM.
l 'ATMP: +20.0°C' – This shows the ambient temperature received from the ambient air temperature sensor.
If error conditions exist, the following table shows the values which will be displayed.
Test Function No. 8 – Momentary Values for Effective and Displayed Speed in km/h
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button.
l 'V: 98 km/h' – shows the momentary effective speed.
l 'VAnz: 101 km/h' – shows the displayed speed, compensated for speed signal input error.
Test Function No. 9 – Battery Voltage Supply to Instrument Pack in Volts
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button.
This function allows the operating voltage applied to the instrument pack to be checked. The value is calculated
by measurement of the stabilized 5V internal voltage and monitoring of voltage drop internally within the
instrument pack.
l 'UB: 13.2V' – Shows battery voltage.
Signal Error Condition Test Function display
Engine coolant temperature via direct
connection to sensor
Short circuit of sensor input to battery
voltage
KTMP: -128°C
Short circuit of sensor input to ground KTMP: -128°C
Engine coolant temperature via CAN
signal
Coolant temperature error KTMP: -128°C
Ambient temperature Short circuit of sensor input to battery
voltage
ATMP: -40°C
Short circuit of sensor input to ground ATMP: -40°C
Engine speed via CAN Engine speed = 0 N: 65535 U/MIN
INSTRUMENTS
88-28 DESCRIPTION AND OPERATION
Test Function 10 – Read Country Code
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button.
The language and country code is programmed into the instrument pack EEPROM at the factory, but can be
changed using TestBook/T4.
l 'LAND: 07 CDN' – shows the country code programmed in the instrument pack.
The following table shows the code and abbreviation for the available markets. Note that the on-board computer
language variants for CDN, AUS, GULF and ZA use the same display texts as GB.
The country code does not only define the language displayed in the message centre, but also defines if the odometer/
trip meter display is in miles or kilometres and if the temperature display is in Celsius or Fahrenheit.
Test Function No. 11 – Read Units Display
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button.
The unit coding of the on-board computer, clock and ambient temperature is programmed at the factory during
build and is stored in the EEPROM. This coding can be queried using this function. The unit coding is shown in
hexadecimal form for each individual byte. The following shows the coding for bytes 1 and 2. When byte 3 is
reached the display changes to byte 1 again.
l 'EINHEIT 1: 00' – hexadecimal value for byte 1.
l 'EINHEIT 2: 00' – hexadecimal value for byte 2.
l The units for °C or °F or 24 hour or 12 hour clock for example, can be changed using TestBook/T4 to change the
bit assignments for bytes 1, 2 and 3. Refer to TestBook/T4 for details of units which can be changed.
Test Function No. 12 – Average Speed for Arrival Time Calculation
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The following data
can be scrolled through using the trip reset button.
This function shows the average speed used for calculation of the arrival time and also the momentary arrival
time value.
l 'VANK: 136.5 km/h' – this shows the average speed used for arrival time calculation.
l 'ANK: 23:46' – this shows the momentary arrival time.
l The calculation of average speed uses signals from the ABS ECU for speed and distance to produce the average
speed value. After the system is reset, a default average value of 40 km/h is used, until the vehicle is moving
again with the engine running.
When the vehicle is stationary, with the engine running, the calculation of average speed is interrupted. The
arrival time is adjusted by monitoring the clock. Every full minute that passes on the clock, with the vehicle
stationary, is added to the arrival time.
Country Country
Code
Abbreviation Countries
Germany 00 D Austria, Germany, Switzerland
English UK 01 GB United Kingdom, Cyprus, Denmark, Finland, Greece,
Iceland, Norway, Sweden, Australia, Japan, Asia
English US 02 USA USA
Italy 03 I Italy
Spain 04 E Spain, Canary Islands, South America, Portugal
English Japan 05 J Japan
France 06 F France, Belgium
CDN 07 CDN Canada
AUS, GULF, ZA 08 AUS/GULF Australia, Gulf States, South Africa
INSTRUMENTS
DESCRIPTION AND OPERATION 88-29
Test Function No. 13 – Activation of the Chime Signals
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19.
This function provides for testing of the instrument pack sounder in the fascia closing panel, below the steering
column. When the function is selected, 'CHIME?' appears in the message centre. Pressing the trip reset button
once activates the three available chime signals as follows:
l Chime T1 – activated for 100 milliseconds with a 2.5 second pause. Used for the MEMO signal.
l Chime T2 – activated for 100 milliseconds with a 2.5 second pause. Used for the Ambient temperature
warning.
l Chime T1 and T2 – activated for 100 milliseconds with a 2.5 second pause. Used for LIMIT/CODE warning.
l Chime T3 – Activated for 100 milliseconds with a 2.5 second pause. Used to indicate check control
messages.
Test Function No. 14 – Read Self Diagnostic Error Bytes
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. Errors are stored in
the EEPROM in the form of bytes and are displayed in hexadecimal form. The maximum five errors can be
scrolled through using the trip reset button and are displayed as follows:
l 'DIAG: 1 90 84 040' – the first number shows the error location number 1 - 5. The following numbers show
error source code, type of error and frequency of error occurrence.
l TestBook/T4 must be used to interrogate the EEPROM and convert the hexadecimal values into meaningful error
descriptions.
Test Function No. 15 – Display of Input/Output Port Status
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. The individual ports
can be scrolled through using the trip reset button.
l 'PORT: A03 11010001' – shows the inputs and outputs for microprocessor 1 in binary format.
l 'PORT: B01 01001110' – shows the inputs and outputs for microprocessor 2 in binary format.
l This function allows for rapid vehicle diagnostics by displaying the status of each microprocessor inputs and
outputs in binary format. TestBook/T4 must be used to read the binary code and interpret the code meanings.
Test Function No. 16 – Momentary Value for Engine Oil Temperature
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19.
This function shows the momentary value for the engine oil temperature which is updated every 200 milliseconds.
l 'OELTMP: 83°C'
l The ignition must be in position II for the oil temperature to be displayed. The value is derived from a CAN
message transmitted from the ECM. If an error occurs, the maximum displayable temperature of 207°C is
displayed. The display is only available if set in the coding, if not, only dashes (- - -) are displayed.
Test Function No. 17 – Minute Counter for Radio Controlled Clock
l This function is allocated for future use. Therefore the following blank message appears: 'RCC-EMPF.: - - - MIN'.
Test Function No. 18 – Dimming Parameters
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. This display
comprises a block of six numbers which define the operating parameters of the instrument pack dimmer.
Test Function No. 19 – Lock/Unlock
l The unlock code is known as a checksum of the VIN. The VIN can be obtained from Test Function No. 1. The
numbers of the VIN are added together and the resulting figure equals the checksum. For example, if the VIN is
XA37295 the checksum will equal 26, which in turn equals the unlock code.
Enter the unlock as follows:
l When test function No. 19 is entered, 'LOCK : ON' is displayed
l Press the trip reset button once, 'LOCK : 00' is displayed
l Press the trip reset button until the unlock checksum is reached, i.e. 26
l Press the check control button once, all test functions will be unlocked.
NOTE: All test functions will remain unlocked, even when the ignition is switched off.
l Relock the test functions as follows:
l Go to test function No. 19 and press the trip reset button, 'LOCK : OFF' is displayed
l Press the trip reset button a second time, 'LOCK : ON' is displayed
l Press the check control button or switch the ignition off to relock the test functions.
INSTRUMENTS
88-30 DESCRIPTION AND OPERATION
Test function No. 20 – Entry of Correction Factor for Fuel Consumption
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. This function allows
for the query and alteration of a correction factor for fuel consumption values. Display and entry of the correction
value is a decimal form per thousand.
l 'KVBR: 0980' – this shows a correction factor of 980.
l Entry of the correction factor is in the range of 750 to 1250. On production, the correction factor of 1000,
corresponding to 1.000, is programmed into the EEPROM.
Adjustment of the correction factor is possible using the trip reset button. Each press of the button decreases the
factor by 1. When the minimum of 750 is reached, the display reverts to the maximum of 1250. If the trip reset
button is pressed and held, the value is decreased in increments of 10 to shorten the setting time. When the
desired correction value is reached, entry is achieved by pressing the check control button. The display moves
to test function No. 21.
The new correction value is calculated from the actual average fuel consumption value and the currently
displayed correction factor. The average fuel consumption is calculated by filling the fuel tank at a pump and
dividing the litres used by the distance travelled on the fuel used. The correction factor must relate to units of L/
100km.
The following formula must be used to calculate the correction value, where X = calculated fuel consumption, Y
= fuel consumption recorded by on-board computer, Z = currently displayed correction factor:
(X ÷ Y) x Z = New correction value.
Test Function No. 21 – Software Reset
l This function is locked and needs to be unlocked via the procedure in Function Test No. 19. This function
activates a reset of the software by the processor. This can also be performed using TestBook/T4.
When function 21 is entered the display shows 'RESET?'. If the trip reset button is depressed the system reset
will be performed. If reset is not required, exit the test function by pressing the check control button or turning the
ignition off.
INSTRUMENTS
DESCRIPTION AND OPERATION 88-31
Operation
Warning Lamp Activation
The following warning lamps are illuminated directly by the instrument pack logic or by other control units connected
to the instrument pack. The following table shows the warning lamp functionality.
Refer to table earlier in the instrument description section for warning lamp colour and bulb check applicability.
Function Active Parameters Reason for activation Activated By
Headlamp main beam Ignition switch position II Main beam selected on LCM on the I Bus
Left direction indicator Ignition switch position I or II Left indicator selected on LCM on the I Bus
Right direction indicator Ignition switch position I or II Right indicator selected on LCM on the I Bus
Front fog lamps Ignition switch position II and
headlamps on
Front fog lamps selected on LCM on the I bus
Rear fog lamps Ignition switch position II and
headlamps on
Rear fog lamps selected on LCM on the I bus
Seat belt warning Ignition switch position II Seat belt not fastened and
ignition on in position II for 6
seconds
LCM on the I bus and
instrument pack
Charge indicator lamp Ignition switch position II No charging output from
alternator
Instrument pack hardwired
connection or via CAN
Oil pressure warning Ignition switch position II Engine oil pressure low Instrument pack hardwired
connection
General brake warning Ignition switch position II Brake fluid low LCM on the I bus
Brake pads worn Instrument pack hardwired
connection
Electronic brake
proportioning failure
CAN message
Brake assist Ignition switch position II Brake booster failure CAN message
Dynamic brake control failure CAN message
Brake booster monitoring
failure
CAN message
Handbrake Ignition switch position II Handbrake on Instrument pack hardwired
connection or instrument
pack software
Anti-lock Brake System
(ABS)
Ignition switch position II ABS failure Instrument pack hardwired
connection
ASC-X (4 wheel all speed
electronic traction control)
Ignition switch position II ASC-X controlling failure Instrument pack hardwired
connection or via CAN
message
Low fuel warning Ignition switch position II Tank reserve level reached Instrument pack software
MIL (Check Engine Soon –
NAS)
Ignition switch position II Engine management system
malfunction
Instrument pack hardwired
connection or via CAN
SRS warning Ignition switch position II Airbag malfunction Instrument pack hardwired
connection
Cruise control Ignition switch position II Cruise control active Instrument pack hardwired
connection or via CAN
message
HDC (Hill Descent Control) Ignition switch position II HDC active Instrument pack hardwired
connection or via CAN
message
INSTRUMENTS
88-32 DESCRIPTION AND OPERATION
Warning Lamp Functionality
1 Glow plug warning lamp (diesel only)
2 DSC active warning lamp
3 HDC warning lamp
4 SRS warning lamp
5 ABS warning lamp
6 General brake warning / brake assist warning
lamp
7 Handbrake warning lamp
8 Engine oil pressure warning lamp
9 Battery charge indicator
10 Rear fog lamp active warning lamp
11 Front fog lamp active warning lamp
12 MIL (Check Engine Soon – NAS)
13 Cruise control active warning lamp
14 Seat belt warning lamp
Functionality for each warning lamp is described below. Some warning lamps, when illuminated, are accompanied by
a chime from the sounder and a message in the instrument pack message centre.
Glow Plug (Diesel models only)
The glow plug warning lamp is illuminated by the ECM and the instrument pack software. The glow plug warning lamp
illuminates in an amber colour when the ignition is moved to position II. There is no bulb check function for this lamp.
The lamp is illuminated by signals from the ECM which equate to the time which the glow plugs are energised. When
the glow plug heating time is complete, the lamp is extinguished. The lamp illumination is accompanied by a message,
'PRE HEATING', in the message centre.
The glow plug warning lamp also serves a second function for the EDC system. If a major EDC system fault occurs
when the engine is running, the glow plug warning lamp will be illuminated permanently and a message generated in
the message centre. The driver must seek attention to the engine management system at a Land Rover dealer as
soon as possible.
Dynamic Stability Control (DSC)
The DSC warning lamp is controlled by the ABS ECU and the instrument pack software. The lamp illuminates briefly
in an amber colour when the ignition is moved to position II. If DSC is selected off, the lamp remains illuminated.
When DSC is active, the lamp flashes to inform the driver that the system is regulating engine output and braking
forces. If the warning lamp remains illuminated after the engine is started or illuminates when driving, the DSC system
has a fault or DSC has been deselected using the fascia switch.
M88 0349
13
123
7
6
5 4
14
12
10
8
11
9
INSTRUMENTS
DESCRIPTION AND OPERATION 88-33
If the vehicle battery has been disconnected, the DSC will be deactivated and the warning lamp will remain illuminated
at ignition on when the battery is reconnected. The DSC can be reactivated by driving the vehicle a short distance or
by turning the steering fully from lock to lock with the engine running. Reactivation is indicated by the warning lamp
extinguishing.
Hill Descent Control (HDC)
The HDC warning lamp is controlled by the ABS ECU and the instrument pack software. The lamp illuminates briefly
in a green colour when the ignition is moved to position II. The lamp is also illuminated when HDC is selected on and
the vehicle speed is less than 20 mph (35 km/h).
If HDC is selected on and the vehicle speed is faster than the operating speed, the lamp will flash and a message 'NO
HDC, SLOW DOWN' will be displayed in the message centre.
If the use of HDC causes the brake discs to exceed their pre-determined temperature, the HDC initiates 'fade out'.
The lamp flashes during 'fade out' and a message 'HDC TEMP.NOT AVAIL' will be displayed in the message centre.
When the brake discs have cooled, HDC is reactivated, the lamp illuminates and the message is removed from the
message centre.
Supplementary Restraint System (SRS)
The SRS warning lamp is controlled by the SRS DCU and the instrument pack software. The lamp illuminates briefly
in a red colour when the ignition is moved to position I (AUX). If a fault is detected in the SRS system, the DCU
illuminates the SRS warning lamp continuously.
Anti-lock Brake system (ABS)
The ABS warning lamp is controlled by the ABS ECU and the instrument pack software. The lamp illuminates briefly
in an amber colour when the ignition is moved to position II. If the lamp remains illuminated or illuminates when driving,
a fault with the ABS system has occurred.
If the vehicle battery has been disconnected, the ABS will be deactivated and the warning lamp will remain illuminated
at ignition on when the battery is reconnected. The ABS can be reactivated by driving the vehicle a short distance or
by turning the steering fully from lock to lock with the engine running. Reactivation is indicated by the warning lamp
extinguishing.
General Brake Warning / Emergency Brake Assist Warning
This warning lamp displays a number of conditions to the driver as follows. The lamp can be illuminated in an amber
or red colour depending on the existing fault condition. The lamp is illuminated, flashing alternately between an amber
and red colour, for a brief period with the ignition in position II. If no fault conditions exist, the lamp is extinguished
after the bulb check period.
The functions of the general brake warning lamp are assigned in priority. Fault conditions which use a red illumination
have priority over amber illuminated faults.
Brake Pad Wear
l The front brake pads are fitted with a wear indicator system. The LH and RH pads are wired in series to the
instrument pack which continuously monitors the circuit. When one or both pads wear to their allowed limit, the
indicator circuit is broken and detected by the instrument pack software.
The instrument pack illuminates the general brake warning lamp in a red colour. The instrument pack
simultaneously, transmits a message to the LCM which displays 'CHECK BRAKE PADS' in the message centre.
When the brake pads are replaced, the instrument pack withdraws the message and the warning lamp
illumination when the ignition is in position II, the engine is not running and the vehicle is not moving for 30
seconds.
Electronic Brake Distribution (EBD) Warning
l If a failure of the EBD function occurs, the ABS ECU passes a message to the instrument pack. The pack
software illuminates the general brake warning lamp in a red colour for as long as the fault condition exists.
INSTRUMENTS
88-34 DESCRIPTION AND OPERATION
Low Brake Fluid Warning
l The brake fluid reservoir is fitted with a sensor which reports the fluid level to the LCM. When the ignition is
switched to position II, the LCM checks the fluid level immediately. To prevent false warnings when the vehicle
is moving, the LCM then monitors the fluid level with a 25 second delay.
If the LCM detects a low brake fluid situation the LCM displays 'CHECK BRAKE FLUID' in the message centre.
Simultaneously, a message is sent to the instrument pack which evaluates the message via the pack software
and illuminates the general brake warning lamp in a red colour, accompanied by an intermittent chime from the
sounder.
Emergency Brake Assist Warning
l If a failure of the emergency brake assist function occurs, the ABS ECU issues a CAN message which is received
by the instrument pack. The instrument pack illuminates the general brake warning lamp in an amber colour for
as long as the failure message is present on the CAN.
Handbrake
The handbrake warning lamp is controlled by the LCM and the instrument pack software. The lamp is illuminated in
a red colour briefly with the ignition in position II. If the handbrake is applied, the lamp remains illuminated, until the
hand brake is released.
If the vehicle is driven with the handbrake applied, the LCM monitors the vehicle speed. When the speed reaches 3
mph (5 km/h), the LCM displays 'RELEASE HANDBRAKE' in the message centre, accompanied by an intermittent
chime from the sounder for 20 seconds.
Engine Oil Pressure
The lamp illuminates in a red colour at all times with the ignition in position II and the engine not running. If the lamp
remains illuminated when the engine is started or illuminates when driving, the engine oil pressure is low and the
engine must be stopped immediately to prevent serious damage to the engine internal components. When the lamp
illuminates with the engine running, the instrument pack displays 'STOP! ENGINE OIL PRESS' in the message centre.
Battery Charge Indicator
The battery charge indicator warning lamp is controlled by the ECM and the instrument pack software.
The battery charge indicator illuminates in a red colour with the ignition in position II and the engine not running. If the
lamp remains illuminated when the engine is started or illuminates when driving, the alternator charge output has
failed.
Rear Fog Lamp
The rear fog lamp operation is controlled by the LCM. The rear fog lamps can only be selected on when the ignition
switch is in position II, the light switch is in the side lamp or headlamp position and the front fog lamps are selected
on. The rear fog lamp warning lamp illuminates when the rear fog lamps are active. The warning lamp is extinguished
if the rear fog lamps are selected off, the front fog lamps are selected off, the light switch is selected off or the ignition
is switched off.
Front Fog Lamp
The front fog lamp operation is controlled by the LCM. The front fog lamps can only be selected on when the ignition
switch is in position II and the light switch is in the side lamp or headlamp position. The front fog lamp warning lamp
illuminates when the front fog lamps are active. The warning lamp is extinguished if the front fog lamp is selected off,
the light switch is selected off or the ignition is switched off.
Malfunction Indicator Lamp (MIL) (Check Engine Soon – NAS)
The MIL operation is controlled by the ECM and the instrument pack software. The lamp illuminates in an amber
colour at all times with the ignition in position II and the engine not running. When the engine is started, the MIL is
extinguished, providing that no OBD related faults are active. If the MIL remains illuminated or illuminates when
driving, a fault is present and must be investigated as soon as possible.
INSTRUMENTS
DESCRIPTION AND OPERATION 88-35
Cruise Control
The cruise control lamp is controlled by the ECM and the instrument pack software. The cruise control lamp is not
illuminated as a bulb check when the ignition is in position II. The lamp illuminates to indicate to the driver that cruise
control has been selected on. The lamp does not inform the driver of the status of the cruise control, i.e.; engaged or
not engaged.
Seat Belt
The seat belt warning lamp is controlled by the SRS DCU, the LCM and instrument pack software.
On vehicles in markets where seat belt buckle switches are not required, the seat belt warning lamp is illuminated in
a red colour briefly with the ignition in position II.
On vehicles in markets where seat buckle switches are required, the seat belt warning lamp is illuminated in a red
colour with the ignition in position II. The lamp is only extinguished when the seat belt buckle switch contacts are
broken by fastening of the seat belt. The illumination of the lamp is accompanied by 'FASTEN SEAT BELTS' displayed
in the message centre and an intermittent chime from the sounder.
Low Fuel Warning
The low fuel warning lamp, located in the fuel gauge, is illuminated in an amber colour briefly with the ignition in
position II. The warning lamp is controlled by the instrument pack software which measures the output signals from
the tank level sensors. If the fuel level falls to or below 12 litres, on V8 models and 10 litres, on T6 models, the
instrument pack illuminates the lamp to inform the driver of the low fuel level.
INSTRUMENTS
88-36 DESCRIPTION AND OPERATION
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Land Rover L322 Range Rover Workshop Manual

Land Rover
Marca
Land Rover
Modelo
L322 Range Rover
Categoría
Carros
Tipo
Workshop Manual
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