2002 LAND ROVER DISCOVERY manual transmission

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
DESCRIPTION AND OPERATION 86-3-33
Cruise control
The Neutral/ Reverse/ Park/ Brake selected output is used by the cruise control system. The BCU checks for the
following inputs:
lIgnition on.
lGearbox state.
lBrake switch activated.
For vehicles with manual transmission, Neutral/ Reverse/ Park/ Brake selected output is on if the ignition is on and
brake switch activated is on. Otherwise, the Neutral/ Reverse/ Park/ Brake selected output is off.
For vehicles with automatic transmission, the Neutral/ Reverse/ Park/ Brake selected output is on if the ignition is on
and brake switch activated is on, or if the ignition is on and 'gearbox state' is in Neutral, Park or Reverse. Otherwise
Neutral/ Reverse/ Park/ Brake selected output is off.
Shift interlock (where fitted)
On automatic gearbox models, the BCU and IDM combine to operate a shift interlock solenoid, so that the gear
selector lever can only be moved when 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.
When the gear selector lever is in the Park position and the ignition is off, an interlock solenoid is de-energised, locking
the gear selector lever in the Park position.
The gear selector lever can only be moved from the Park position when the ignition is switched on and the brake pedal
is depressed. When these conditions are satisfied, the brake pedal switch signal is received by the BCU which then
signals the IDM to energise the interlock relay. When the interlock relay is energised, the interlock solenoid is
operated, unlocking the gear selector lever.
When the brake pedal is released, the feed to the BCU is removed and the shift interlock solenoid is de-energised.
The locking mechanism controlled by the solenoid will lock the gear selector lever once it is returned to the Park
position.
The shift interlock option can be programmed in one of three states dependent on market/ customer requirements,
these are:
lOption 1– not fitted.
lOption 2 – normal operation.
lOption 3 – inhibit transfer box.
The BCU checks the status of the following inputs to determine the logic action for employing the shift interlock
solenoid:
lBrake switch activated.
lIgnition state.
lGearbox state.
In the event of a communications link failure, the shift interlock solenoid enable is switched on for 1 minute every time
the ignition is switched on and switched off when the ignition is turned off.
Ignition interlock (where fitted)
On automatic gearbox models, when the ignition key is inserted in the ignition switch, the ignition key-in switch
contacts close to supply a signal to the BCU to indicate the presence of the key in the switch and provide a supply
feed to the ignition interlock solenoid. If the gear selector lever is in a position other than Park, or the 'transfer box
neutral selected' is on, the BCU will supply an earth path to complete the ignition interlock circuit and cause the
interlock solenoid to be engaged. With the interlock solenoid engaged, removal of the ignition key is prevented. The
BCU will open the circuit, to allow removal of the ignition key, only when the gear selector lever is in the Park position
and the transfer box is in either high or low range.

DRIVING AIDS
86-8-10 DESCRIPTION AND OPERATION
Operation
PDC System Operation
When the ignition switch is in position II and reverse gear is selected, the PDC sensors are automatically activated.
The PDC ECU only activates the system if reverse is selected for more than 1 second. This avoids nuisance audible
warnings when the gear selector lever is being moved between Drive and Park on vehicles with automatic
transmission.
When the system is activated, the PDC ECU illuminates the indicator LED in the PDC switch, switches on the
ultrasonic sensors and generates a single chime on the PDC sounder to indicate the system is active. If an object is
range of the sensors when the system is activated, a series of audible warnings are emitted by the PDC sounder
immediately.
If PDC operation is not required, it can be suspended temporarily by pressing the PDC switch. When reverse is
deselected and subsequently reselected, PDC will automatically become active again.
PDC can also be manually selected when not in reverse gear by pressing the PDC switch. A second press of the
switch is required to turn off the PDC or the PDC will be deactivated if reverse is selected and then deselected.
Sensor Operation
The PDC ECU 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.
The maximum detection range is 1800 mm (70 in). When an object is detected, the time delay between the audible
warning tones decreases as the distance between the detected object and the vehicle decreases until, at
approximately 450 mm (17 in), the audible warning tone is continuous.
After the initial detection of an object, if there is no decrease in the distance between an object and the central sensors,
the time delay between the audible warnings remains constant. If an object is detected by one of the corner sensors
only, the audible warnings stop after about 5 seconds if there is no change in the distance between the object and the
corner sensor.

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
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
88-38 DESCRIPTION AND OPERATION
Gearbox manual/sport mode warning lamps
The gearbox manual/sport mode warning lamps within the instrument pack each utilise a green LED and a clear
legend. On vehicles fitted with an automatic gearbox, operating the manual mode switch instructs the Electronic
Automatic Transmission (EAT) ECU to illuminate the manual mode LED. Operating the sport mode switch instructs
the EAT ECU to illuminate the sport mode LED.
There is no self-test performed at ignition on for this warning lamp.
If the EAT ECU detects a fault it will cause both warning lamps to flash.
The power input for the LED's is supplied by the instrument pack. The EAT ECU applies a high or low voltage to the
instrument pack microprocessor which measures the applied voltage from the ECU and illuminates the appropriate
warning lamp.
The voltage on the earth paths from the EAT ECU to the instrument pack has the following functions:
Warning lamp response Manual earth path, volts Sport earth path, volts
No lamps > 7.7 > 7.7
Sport warning > 7.7 < 1.8
Manual warning < 1.8 > 7.7
Both lamps flash < 1.8 < 1.8

INSTRUMENTS
88-42 DESCRIPTION AND OPERATION
Interior rear view mirror with compass
(where fitted)
1Cover
2Electrical connector
3Mounting bracket
4Light sensor
5Compass LED display
6Compass calibration switch
7Compass printed circuit board
Certain vehicles have an interior rear view mirror that features an automatic photochromatic dimming function and an
electronic compass with LED display.
The compass mirror is a self-contained unit and does not interface with any other vehicle system or electronic control
unit. The mirror is fixed to a metal bracket attached to the windscreen.
A three pin connector provides the electrical connection to the mirror's internal circuit board. Pin-1 of the connector
provides the 12V power supply to the board via the auxiliary relay located in the engine compartment fusebox. When
the ignition switch is turned to the 'II' position, a 12V supply is provided to energise the coil of the auxiliary relay via
fuse 26 in the passenger compartment fusebox. The auxiliary relay's contact supply voltage is provided from the
vehicle battery through fusible links 1 & 7. When the relay's contacts close, a 12V supply is fed to the compass mirror
circuit board via fuse 15 in the passenger compartment fusebox. This is the supply voltage feed for the mirror's internal
compass.
Pin-2 of the electrical connector provides the path to earth.
Pin-3 of the electrical connector is a 12V ignition switched supply voltage (position 'II' of the ignition switch). The
supply voltage is provided to the mirror's circuit board via fuse 25 in the passenger compartment fusebox, and the
reverse lamp switch (normally closed) for vehicles with manual transmission or the starter inhibitor / reverse light
switch (normally closed) for vehicles with automatic transmission. This is the supply voltage feed for the mirror's
photochromatic dimming function.
M88 0297
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