odometer LAND ROVER DISCOVERY 2002 Workshop Manual

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-17
Operation
Refer to illustration.

+ AUTOMATIC GEARBOX - ZF4HP22 - 24, DESCRIPTION AND OPERATION, Control schematic.
When the ignition is switched on, a bulb check is performed on the transmission temperature warning lamp and the
mode warning lamps by the instrument pack and the EAT ECU respectively. The warning lamps are illuminated for
approximately 3 seconds and then extinguished.
The gear position switch outputs are monitored by the BCU and the EAT ECU. The BCU outputs gear position signals
to illuminate the position indicators each side of the gear selector lever and on the odometer LCD in the instrument
pack.
In D, 3, 2, and 1, the EAT ECU outputs control signals to the gearbox to select the required gear.
In D, all forward gears are available for selection by the EAT ECU. In 3, 2 and 1, a corresponding limit is imposed on
the highest gear available for selection. When R is selected, reverse gear only engages if the vehicle is stationary or
moving at 5 mph (8 km/h) or less. When R is deselected, reverse gear only disengages if the vehicle is moving at 4
mph (6 km/h) or less.
Selector lever interlock (where fitted)
The interlock solenoid on the selector lever is de-energised unless the foot brake is applied while the ignition is on.
While de-energised, the interlock solenoid allows the selector lever to move through the range unless P is selected.
On entering the P position, the interlock solenoid engages a latch which locks the selector lever. When the ignition is
on and the foot brake is applied, the BCU energises the interlock solenoid, which disengages the latch and allows the
selector lever to be moved out of P.
Economy, sport and manual modes
During the power-up procedure after the ignition is switched on, the EAT ECU defaults to an economy mode. Pressing
the mode switch causes the EAT ECU to change between the economy mode and the sport or the manual mode,
depending on the range selected on the transfer box:
lIf the transfer box is in high range, the EAT ECU changes to the sport mode and illuminates the sport mode
warning lamp in the instrument pack. In the sport mode the gearbox is more responsive to accelerator pedal
movement. Downshifts occur earlier and upshifts occur later.
lIf the transfer box is in low range, the EAT ECU changes to the manual mode and illuminates the manual mode
warning lamp in the instrument pack. Kickdown is disabled and the EAT ECU maintains the gearbox in the gear
selected on the selector lever (D = 4th gear) to give improved off road performance. Downshifts occur only to
prevent the engine stalling. From a standing start, the vehicle pulls away in 1st gear and, if a higher gear is
selected, upshifts almost immediately to the selected gear (shifts of more than one gear can occur).
After a second press of the mode switch the EAT ECU reverts to the economy mode, for the range selected on the
transfer box, and extinguishes the related mode warning lamp in the instrument pack.
Shift control
To provide the different driving characteristics for each mode of operation, the EAT ECU incorporates different shift
maps of throttle position/engine speed. Base shift points are derived from the appropriate shift map. When a shift is
required, the EAT ECU sends a request to the ECM for a reduction in engine torque, in order to produce a smoother
shift. The percentage of torque reduction requested varies according to the operating conditions at the time of the
request. When the EAT ECU receives confirmation of the torque reduction from the ECM, it then signals the shift
solenoid valves in the gearbox to produce the shift. To further improve shift quality, the EAT ECU also signals the
pressure regulating solenoid valve to modulate the hydraulic pressure and so control the rate of engagement and
disengagement of the brake clutches.

BODY CONTROL UNIT
86-3-10 DESCRIPTION AND OPERATION
Diagnostic socket
RHD illustrated
The BCU has a serial connection to the diagnostic socket to allow unit interrogation using TestBook.
In addition to fault diagnosis, the BCU can be programmed with the following information:
lPlip codes.
lOptions.
lVIN code.
lEKA code.
lEEPROM locking.
The following manufacturing details are programmed into the BCU which can be accessed using TestBook:
lDate of manufacture.
lHardware version number.
lUnit serial number.
lOdometer reading.
It is not possible to use the diagnostic bus to communicate with the BCU via TestBook when the security system is
active (except for passive immobilisation). This is a security measure to ensure that no key programming or market
configuration can take place if the operator is not in possession of a valid remote transmitter or the vehicle keys.
The BCU is normally programmed to accept two remote transmitters, but a further two remote handsets can be
programmed into the BCU and one optional Self Levelling Suspension (SLS) transmitter. All remote transmitters need
to be available if TestBook is to be used to re-configure the BCU.
M86 4705

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-11
Programmable options
The BCU can be programmed with a number of options to satisfy specific market requirements and customer
preferences. The options can be set using TestBook.
Function Option Details
Transmission Manual The vehicle is fitted with manual transmission.
Automatic The vehicle is fitted with automatic transmission.
Front fog lamps None The vehicle is not fitted with front fog lamps.
Main The front fog lamps will operate if the headlamps are on main
beam.
No main The front fog lamps will not operate if the headlamps are on main
beam.
Interlocks None The vehicle is not fitted with key, shift or transfer box interlocks.
Shift The vehicle is fitted with key, shift and transfer box interlocks.
No transfer The vehicle is fitted with key and shift interlocks, but not a transfer
box interlock.
Daylight running lamps None The vehicle is not fitted with daylight running lamps.
No main The daylight running lamps are on if the headlamp main beams
are off.
No heads The daylight running lights are on with headlamp main and dipped
beams off and the gearbox not in Park.
Programmed wash/ wipe Normal The front wipers operate if the front wash is operated.
No wipe The front wipers do not operate if the front wash is operated.
Key-in warning Disabled The ignition key in audible warning is disabled.
Enabled The ignition key in audible warning is generated if the ignition key
is in and the driver's door is open.
Electric front seats None The vehicle is not fitted with electric front seats.
Normal Electric seat adjustment is available for 45 seconds after the
driver's door opens or if the ignition is on.
Ignition II Electric seat adjustment is available if the ignition is on.
Electric front windows Driver cancel The front windows will be disabled 44 seconds after the driver's
door is opened.
All cancel The front windows will be disabled 44 seconds after any door is
opened.
No cancel The front windows will be disabled when the ignition is turned off.
Heated front screen Fitted The vehicle is fitted with heated front screens.
None The vehicle is not fitted with heated front screens.
Rear windows and
sunroofDriver cancel The rear windows and sunroof will be disabled 44 seconds after
the driver's door is opened.
All cancel The rear windows and sunroof will be disabled 44 seconds after
any door is opened.
No cancel The rear windows and sunroof will be disabled when the ignition
switch is turned off.
Gear position indicator
illuminationAlways The automatic gearbox selector illumination is on when the
ignition is on.
Sidelights The automatic gearbox selector illumination is on when the
ignition is on and the sidelights are off.
Hill descent control None The vehicle is not fitted with hill descent control.
Fitted The vehicle is fitted with hill descent control.
Courtesy headlamps Disabled The vehicle is not fitted with courtesy headlamps.
Enabled The vehicle is fitted with courtesy headlamps.
Odometer error warning Disabled The odometer will not flash if there is an odometer error.
Enabled The odometer will flash if there is an odometer error.

BODY CONTROL UNIT
86-3-16 DESCRIPTION AND OPERATION
Headlamps
The BCU contains a feature which allow the vehicle headlamps to be turned on when the remote transmitter is
pressed (courtesy headlamps).
For markets with daylight running lamps, the BCU controls the logical operation of the daylight running lamps. Options
are daylight running lamps are on if the main beam headlamps are off, or the daylight running lamps are on with main
and dipped beam off and the gearbox not in Park.
Front fog lamps
For markets with front fog lamps fitted, the BCU controls the operation of the front fog lamps. Options can be selected
so that the fog lamps will operate with or without the headlamps on main beam.
Instrument pack
The BCU communicates with the instrument pack via a serial data bus.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
lThe instrument pack provides the BCU and IDM with details of vehicle speed.
lSignals are provided from the IDM to the instrument pack and BCU when the direction indicator lamps are active.
lFor certain markets, the BCU provides a signal to the instrument pack for indicating when the transfer box is in
neutral.
lThe IDM can signal the instrument pack to illuminate a trailer warning lamp. This operates when the IDM senses
that the current drawn by the indicator circuit exceeds a preset threshold.
lThe odometer reading displayed on the instrument pack LCD screen is also stored in non volatile memory in the
BCU. Whenever the ignition is turned from position I to position II, the instrument pack and the BCU compare
their stored values.
lThe gear selector position is displayed on the instrument pack LCD screen under the direction of the BCU.
Starting
The starting system comprises a starter motor and solenoid located at the rear right hand side of the engine. A starter
relay controlled by the BCU is used to supply battery power for starter solenoid operation. The starter motor receives
its feed directly from the battery.
Cruise control
The BCU processes several signals used for cruise control:
lWhen the brake pedal is pressed, a low voltage brake lamp signal is sent via the BCU to the cruise control ECU.
lThe gear position switch sends an input via the BCU to the cruise control ECU if the selector lever is in Park,
Neutral or Reverse.
lA voltage supply is fed from the BCU to the cruise control SET+ switch.
lA voltage supply is fed from the BCU to the cruise control RES switch.
On vehicles with automatic transmission, if the BCU receives an input from the gear position switch or the brake pedal
switch, the BCU sends a signal to the cruise control ECU to cancel or inhibit cruise control operation.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - cruise control.
Shift interlock (where fitted)
On automatic gearbox models, the BCU and IDM combine with an interlock relay located in the passenger
compartment fuse box to operate a shift interlock solenoid, so that the gear selector lever cannot be moved out of
Park until certain logical conditions have been satisfied. Operation of the interlock may be affected, if the battery
becomes discharged.

+ AUTOMATIC GEARBOX - ZF4HP22 - 24, DESCRIPTION AND OPERATION, Description.

BODY CONTROL UNIT
86-3-32 DESCRIPTION AND OPERATION
Odometer update
The BCU can be programmed for one of two options:
lOption 1 – no odometer error warning.
lOption 2 – odometer error warning.
In order to provide an LCD flash request to the instrument pack via the communications link, the following inputs are
checked:
lIgnition state.
lInstrument pack odometer value (via the communications link).
lBCU odometer value.
The function is only active when the ignition state is on. The maximum allowed value is 999,999 miles (1,608,999
km).If the instrument pack odometer value is greater than the maximum allowed value, the maximum value is
assumed. The BCU odometer value is stored in EEPROM. If 16 identical values of the instrument pack odometer
reading is received consecutively, the instrument pack odometer value is compared with the BCU odometer value. If
the consecutive readings from the instrument pack differ, the BCU odometer value is incremented accordingly. If the
BCU odometer value is less than the instrument pack odometer value by up to 10 km, the BCU odometer value is set
equal to the instrument pack odometer value.
If the odometer warning option is enabled, and the contents of the instrument pack odometer value buffer is identical
to, or greater than BCU odometer value
± 10 km, the BCU sends an LED flash request to the instrument pack.
In the event of a communications link failure, this function will be unable to operate.
Gear position indicator illumination
On automatic gearbox models, two variations of illumination for the gear position indicators on the selector lever can
be programmed into the BCU. In option 1, illumination is provided when the ignition is on. In option 2, illumination is
enabled when the ignition is on and the side lamps are off.
Starter relay
The BCU checks the status of the following inputs and internal BCU conditions to determine whether or not to provide
an output to enable the starter relay:
lAutostart inhibit (vehicles with automatic gearbox only).
lSecurity start inhibit (immobilisation check).
lEngine running (link to instrument pack).
lEEPROM locked (internal check).
lIDM and BCU matched.
When the BCU receives a crank signal from the ignition switch, an earth path is completed to the starter relay coil,
provided that the security system has been de-activated. If the ECM has not received a valid unlock/ remobilise signal,
the starter relay will be disengaged and the engine stopped. The BCU also receives an engine running signal from
the instrument pack, so that if the ignition key is turned to the crank position while the engine is running, the starter
motor relay will not be engaged.
If the logic conditions are correct to allow starter operation, the completion of the earth path from the starter relay coil
to the BCU energises the coil and the relay contacts close to supply battery power to the starter motor.
When the ignition switch is released from the crank position, the power supply feed from the ignition switch to the
starter relay coil is interrupted and the relay contacts open to prevent further battery feed to the starter motor.
If a communications link failure is experienced, the BCU will be prevented from detecting the 'engine running'
condition and the BCU will default to assume that the engine is not running.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-1
INS TRUMENTS DESCRIPTION AND OPERAT ION
Instrument pack
1Hill descent control information warning lamp
2Overspeed warning lamp
3Brake system warning lamp
4Malfunction Indicator Lamp (MIL)
5Tachometer
6Direction indicator warning lamp
7Main beam warning lamp
8Direction indicator warning lamp
9Speedometer
10SRS warning lamp
11Off road mode warning lamp
12Glow plug warning lamp
13Trailer warning lamp
14Water in fuel filter warning lamp
15Transmission high temperature warning lamp
16Seat belt warning lamp17Fuel tank level gauge
18Low fuel level warning lamp
19LCD odometer/trip meter
20Anti-theft status warning lamp
21ABS warning lamp
22Gearbox manual/sport mode warning lamp
23Alternator charge warning lamp
24ACE warning lamp
25Oil pressure warning lamp
26SLS warning lamp
27Hill descent control warning lamp
28Engine coolant temperature gauge
29High coolant temperature warning lamp
30Traction control warning lamp
31Differential lock warning lamp
32Transfer box neutral warning lamp

INSTRUMENTS
DESCRIPTION AND OPERATION 88-5
Description
General
The instrument pack consists of four analogue dials, four warning lamp packs and a Liquid Crystal Display (LCD)
odometer.
The four dials are used to indicate:
lRoad speed.
lEngine speed.
lFuel tank level.
lEngine coolant temperature.
The dials are driven by a microprocessor from information received from the serial communication link. Information
input is received as either:
lDigital.
lAnalogue.
lPulse train.
lPulse Width Modulation (PWM).
The LCD provides information for:
lOdometer.
lTrip distance.
lSelected gear (on vehicles fitted with an automatic gearbox).
A trip reset button is provided to zero the trip display, this button also allows the selection of "miles" or "kilometres"
for the display. A photocell controls the illumination of the LCD, maintaining contrast of the display during ambient light
changes.
Within the four warning lamp packs there are 28 lamps. A long life bulb illuminates the high beam warning lamp and
the rest of the warning lamps are illuminated by Light Emitting Diodes (LED's). All warning lamp legends are invisible
until lit. When lit the symbols are illuminated on a black background.
The warning lamps illuminate in one of four colours. The colour indicates the level of importance to the driver, as
follows:
lRed = warning.
lAmber = caution.
lGreen = system operative.
lBlue = main beam operative.
The first warning lamp pack is located in the top left-hand side of the instrument pack and contains the following
warning lamps:
lTraction control warning lamp.
lTransfer box in neutral warning lamp.
lDifferential lock warning lamp
lOverspeed warning lamp (activated for gulf market only).
lBrake system warning lamp.
lHill Descent Control (HDC) information warning lamp.
lMalfunction Indicator Lamp (MIL)/ SERVICE ENGINE SOON warning lamp.
The second warning lamp pack is located in the centre of the instrument pack and contains the following warning
lamps:
lDirection indicator warning lamps.
lHigh beam warning lamp.
lAnti-lock brake system warning lamp.

INSTRUMENTS
88-6 DESCRIPTION AND OPERATION
The third warning lamp pack is located in the top right-hand side of the instrument pack and contains the following
warning lamps:
lSRS warning lamp.
lSLS off road mode warning lamp.
lTrailer warning lamp.
lGlow plug warning lamp.
lWater in fuel filter warning lamp.
lSeat belt warning lamp.
lTransmission high temperature warning lamp.
The fourth warning lamp pack is located underneath the tachometer of the instrument pack contains the following
warning lamps:
lOil pressure warning lamp.
lAlternator charge warning lamp.
lHDC fault warning lamp.
lSelf Levelling Suspension (SLS) warning lamp.
lActive Cornering Enhancement (ACE) warning lamp.
lGearbox manual/sport mode warning lamps.
The serial communication link is used to allow information to travel to and from the instrument pack, and it provides
the ability to configure the instrument pack to a specific market. It also allows the instrument pack to be controlled by
TestBook for diagnostics.
There are five market specific variants of the instrument pack:
lUnited Kingdom (UK).
lNorth American Specification (NAS).
lCanada.
lAustralia.
lRest Of the World (ROW), Gulf and Japan.
The main difference between the five markets is that the speedometer will indicate road speed in mph as major figures
and km/h as minor figures, km/h as major figures and mph as minor figures or km/h only.
When TestBook is used to diagnose the instrument pack it demands each of the dials and warning lamps to operate
in-turn so a visual check of their operation can be made.
CAUTION: The instrument pack must not be stored on its face side at any time. This is because the dials have
damping fluid within them to ensure smooth operation of the dials' indicator needles. This fluid will leak out.
Speedometer
The speedometer informs the driver of the current vehicle road speed. It has a Liquid Crystal Display (LCD) to show
odometer, trip meter and, on automatic gearbox models, the selected gear. The speedometer will not show speeds
of less than 1.5 mph (2.5 km/h).
There are three different market configurations:
lNAS and UK = mph as major figures km/h as minor figures.
lCanada = km/h as major figures mph as minor figures.
lROW and Australia = km/h only.
The Self Levelling and Anti-Lock Brake System (SLABS) ECU provides the signal input for the road speed. The signal
is at 8000 pulses per mile (1.6 kilometres).

INSTRUMENTS
DESCRIPTION AND OPERATION 88-7
LCD odometer/trip meter
The LCD has 3 different display elements:
lOdometer.
lTrip meter.
lSelected gear (on vehicles with automatic gearboxes).
The odometer displays units in either miles or kilometres. It has a range from 0 to 999,999 units, only full units are
displayed irrespective of the type of units selected, the display will stop at 999,999 units. TestBook can be used to
reset the odometer. This is allowed only once and must be carried out before 150 miles (240 km) from new, after this
distance the feature is disabled. The odometer may lose up to one km (0.6 miles) when the battery is reconnected,
this is due to the software incorporated into the instrument pack to prevent anyone tampering with the odometer
reading.
The trip meter displays units in either miles or kilometres and has a range of 0.0 to 999.9 units. The display rolls over
from 999.9 to 0.0 units. Units down to one tenth of a mile or one tenth of a kilometre are displayed. The trip meter
displays 0.0 when the battery is reconnected or charged from a discharged state.
A push button located next to the LCD is utilised to reset the trip meter to zero and to change the units from miles to
kilometres. Pressing the button for less than 2 seconds allows the display to reset to zero. Pressing the button for
more than 2 seconds changes the units from miles to kilometres and vice versa. The units will only change for UK,
NAS and Canadian market vehicles.
The selected gear displays when the automatic gearbox is in park, reverse, neutral, drive 3,2,1, by using the letters
or numbers PRND321 in the display.
The data input for the LCD odometer/trip meter is from the SLABS ECU for the distance input and from the BCU for
the gear position. The instrument pack provides the earth path to illuminate the gear position warning lamp.
If a replacement instrument pack is required TestBook must be used to retrieve the odometer reading, so that when
the new instrument pack is fitted the odometer reading can be programmed in.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-41
Diagnostic connector
RHD illustrated
The diagnostic connector allows TestBook to communicate with the vehicle electrical system.
The modules that TestBook can interface with via the diagnostic connector are:
lSLABS ECU.
lBCU.
lECM (V8 and Td5).
lIDM.
lACE ECU.
lEAT ECU.
lSRS DCU.
TestBook communicates with the ECM, ECU's and the instrument pack for diagnostic purposes and for configuration
for a specific options or market. If communications on the diagnostic connector fail for greater than three seconds after
the ignition is in position II the gear selected display in the LCD flashes. This applies to both manual and automatic
vehicles in all markets.
The instrument pack options configured by TestBook are:
lAutomatic or manual gearbox fitted.
lDiesel or V8 engine fitted.
lACE fitted.
lSLS fitted.
lGulf, Japan or ROW markets.
lService engine reset.
lOdometer reset.
lHDC fitted.
lTraction control fitted.
The serial communications link is a bi-directional communications network providing both input and output on the
same pin.
M86 4705