Range Rover Automatic Transmission. Manual - part 11

System Information Document

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2.2.8 Diagnostic interface

2.2.8.1 Pin 31 - Diagnostic line (K line)

The K line is the main interface between the on board electronic control units and external diagnostic
devices as customer specific testers, Scantool, development tools or end of line programmers.

Customer specific testers are used to read diagnostic data from the fault memory, to manipulate
diagnostic data and / or manipulate other data like country variants or calibration data. Scantools are
used to access the OBDII relevant entries in the fault memory and to manipulate them.

Development tools are used to display and to manipulate random data of the EAT including the fault
memory.

- Component

The physical and transfer layer must be compatible to ISO9141 and ISO9141 CARB. The EAT
supports the application and protocol layer of ISO9141 CARB. Other customer specific
protocols can be implemented.

- Control unit

- interface characteristic

Digital input / output

- signal form

Square wave

- voltage levels

compliant to ISO 9141

- input resistance

compliant to ISO 9141

- data transfer rate

10.4 kBaud for CARB diagnostics
Other supported protocols, see relevant specification.

System Information Document

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2.3 ECU Connector Pin-out

Function

Wire Colour

Function

Wire Colour

Not used

Solenoid Valve 1; MV1

Not used

K Line (Diagnostic line)

Not used

Solenoid valve 3; MV3

Pressure regulator

Solenoid valve 2; MV2

Power Ground

Not used

Position Switch Line 2 (X)

Position Switch Line 1 (W)

Position Switch Line 4 (Z) (GS8.87.0 only)

Position Switch Line 3 (Y)

Not used

High / Low Range Input

Not used

Output speed sensor -

Output speed sensor +

Output speed sensor screen

Not used

CAN – High

CAN – Low

Not used

Mode Switch

Not used

MES Line 1

Not used

MES Line 2

Supply, Solenoids & PR

Permanent Battery Supply

Ignition Battery Supply

Not used

Electronic Ground

System Information Document

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[Revision: 2.3]

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2.4 Vehicle connector pin outs

2.4.1 Diagnostic Connector

2.4.2 Harness to Position switch (mounted on Transmission)

12V supply

Line 1

Line 2

Line 3

Line 4

10 -

2.4.3 Harness to Solenoid Valves (mounted on Transmission)

Pin 4

+12V

Pin 16

K Line

Pin 7

System Information Document

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[Revision: 2.3]

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© Rover Group 1998

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3 Description of Functionality

In an Electronic Automatic Transmission, the hydraulic valve block is replaced with an Electronically controlled hydraulic
valve block. This allows the shift points and valve pressures to be calibrated individually for every possible situation. The
result is an improvement in shift quality, and increased torque capacity and more flexibility of shift patterns.

The Electronic Control Unit is programmed with software which monitors all the relevant electrical inputs required to decide
what type of shift should be made. As well as this information, several special features exist within the software to improve
the drivablility and functionality of the Vehicle.

3.1 Special features

3.1.1 Sport Mode.

In order to activate the sport mode, the “mode” button must be pressed whilst the vehicle is in high range. This will make the
vehicle more responsive to accelerator pedal movement, changing down gears sooner than would be the case in the default
normal mode.

3.1.2 Manual Mode.

In order to activate the manual mode, the “mode” button must be pressed whilst the vehicle is in low range. This mode is
designed to give improved off road performance. If the vehicle is in manual mode, the position of the selector will refelect the
gear engaged, rather than the maximum gear required. For example, if the selector position is in “3” whilst driving in normal
modes, gears 1,2 and 3 will be available However, in manual mode, if position “3” is selected, the transmission will select
3rd gear very shortly after pulling away from rest. Kickdown is disabled in this mode.

3.1.3 Towing / Driving up steep gradients

When the vehicle is in its normal default mode (ie, High range with sport not selected) the transmission will select a shift
pattern approriate the the current conditions. If either a heavy trailer is being pulled, or a steep gradient is being climbed, the
transmission will hold onto gears longer than would normally be the case to aid performance and drivability.

3.1.4 Compensation for reduced engine torque

In a similar way to the Towing mode, if the vehicle is producing less torque than would normally be the case (high altitude or
very hot air into the engine) then the transmission will hold onto gears longer than would normally be the case. This is a very
similar situation to towing, but the performance of the vehicle is reduced due to a lack of engine power, rather than the weight
of the vehicle.

3.1.5 Calibration Selection (99MY V8 Range Rover Only)

ECU part numbers differentiate between North America, UK/Euro and Rest of world. Each ECU contains two calibrations,
4.0l and 4.6l. When an ECU is fitted to a vehicle, the correct calibration must be selected, or a gearbox fault will be stored,
and “Gearbox fault” will be displayed in the message centre. The vehicle can be driven in this state, and is not in limp home
mode. However, vehicles must not be driven for long in this state.

When the correct calibration is selected (4.0l or 4.6l), the fault code memory is deleted automatically. If the ECU is removed
from the vehicle, the correct calibration is remembered. For this reason, it is important that if ECU’s are swapped between
vehicles, the correct calibration must be selected.

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