transmission LAND ROVER DISCOVERY 2002 Repair Manual

HEATING AND VENTILATION
DESCRIPTION AND OPERATION 80-5
Heater assembly
1Windscreen and side window air outlet
2Face level air outlet
3Casing
4Rear footwell air outlet
5Front footwell air outlet
6Drain outlet
7Air inlet8Engine coolant return
9Engine coolant feed
10Heater matrix
11RH temperature control cable
12Distribution control cable
13LH temperature control cable
The heater assembly heats and distributes air as directed by selections made on the 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 moldings, which contains a heater matrix and control flaps. 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 connect to overboard drain tubes installed in the
sides of the transmission tunnel.
Heater matrix
The heater matrix provides the heat source to warm the air being supplied to the distribution outlets. The heater matrix
is an aluminium two pass, fin and tube heat exchanger, installed in the RH side of the casing. Two aluminium tubes
attached to the heater matrix extend through the engine bulkhead to connect the heater assembly to the engine
coolant system. When the engine is running, coolant is constantly circulated through the heater matrix by the engine
coolant pump. On diesel models, the coolant flow is assisted by an electric pump while the FBH system is active.

WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-17
Front flick wipe
Flick wipe operation will only activate when the following conditions are met:
lIgnition switch is in position I or II.
lFront flick switch is operated.
Pressing the flick wipe switch operates the front wiper motor at high speed. The front wiper motor operates as long
as the flick switch is activated. Releasing the flick switch causes the front wiper motor to run through the park switch
circuitry. The park switch only permits low speed operation. Thus if the flick switch is pressed and immediately
released, the wipers operate at low speed.
Rear intermittent wipe variable delay
The rear intermittent wipe variable delay operation allows the driver to adjust the interval between wipes to suit local
conditions. Rear variable delay operation only activates if the following conditions are met:
lIgnition switch in position I or II.
lFront wash/ wipe switch on intermittent.
lRear wipe switch is operated.
The BCU determines the desired delay interval based on the setting of the variable delay switch. The rear wash/ wipe
delay is nominally twice as long as that of the front. This information passes from the IDM to the rear wiper relay and
activates the rear wiper motor.
If the delay duration is decreased during operation of the rear wiper, the wipers immediately operate once and the
delay cycle is reset.
If the delay duration is increased during operation of the rear wiper, the delay cycle is automatically increased by the
BCU.
Reverse wiping
Reverse wiping operates the rear wiper motor when reverse gear is selected. The transmission must be in reverse
for longer then 0.5 seconds before reversing wipe activates. Reversing wipe activates if the following conditions are
met:
lIgnition switch is in position II.
lReverse gear is selected.
lRear wiper or front wipers operating.
If the rear wiper is active in any mode when reverse gear is selected, the rear wiper activates for 4 second. After 4
seconds the rear wiper operates in a delay operation at the same delay interval set by the variable delay switch until
reverse gear is deselected.
If the front wipers are operating on either low or high speed when reverse gear is selected, the rear wiper activates
continuously until reverse gear is deselected.
In order to enable reversing wipe functions, the BCU utilises the reversing light switch located within the transmission
to determine when reverse gear has been selected.
If the front intermittent wipe is active when reverse gear is selected, the rear wiper completes 2 cycles before operating
at the same intermittent delay as the front wipers.

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
DESCRIPTION AND OPERATION 86-3-17
Ignition key interlock (where fitted)
On automatic gearbox models, the ignition key interlock solenoid prevents removal of the ignition key from the ignition
switch when the transmission gear selector is not in the Park position. The logic control operation for this is performed
by the BCU.
Transfer box interlock (where fitted)
On automatic gearbox models, a transfer box interlock solenoid is controlled by the IDM to prevent transfer box shift
lever being moved out of high or low range unless certain conditions have been satisfied. The IDM controls the
operation of the transfer box relay which is located in the passenger compartment fuse box.

+ TRANSFER BOX - LT230SE, DESCRIPTION AND OPERATION, Description.
Gear position switch
A gear position switch is located on the automatic gearbox and is used to inform the BCU of the gear selector lever
position. The BCU has four sensing inputs from the gear position switch contacts W, X, Y, Z, which are used to
determine the gearbox drive status at any particular instance. The BCU gives an output corresponding to the gearbox
status derived from the gear position switch inputs. The logic states defining the gear selector positions are listed in
the table below, where Z1, Z2, Z3 and Z4 represent intermediate states which exist as the selector lever position is
changed:
The existence of an intermediate state causes a fault code to be detected by the BCU. To reduce the chances of the
fault condition occurring while changing selector lever position, the inputs are debounced and only considered valid
when they have existed for at least 33 ms.
Transmission neutral selector
The transmission neutral sensor provides an earth signal to the BCU when the transfer box is in neutral. The earth
signal causes the BCU to operate an audible warning when the transfer box is in neutral with the ignition switched on.

+ TRANSFER BOX - LT230SE, DESCRIPTION AND OPERATION, Description.
Gear position Switch contacts
WX Y Z
P (Park) 1 0 0 0
Z11100
R (Reverse) 0 1 0 0
Z11100
N (Neutral) 1 1 1 0
Z21010
D (Drive) 1 0 1 1
Z31111
30111
Z40011
20001
Z40011
10010

BODY CONTROL UNIT
86-3-18 DESCRIPTION AND OPERATION
Self levelling suspension and ABS
The BCU communicates with the SLABS ECU for several functions:
lAn output is provided from the SLABS ECU to the BCU to provide the logic conditions for issuing the SLS audible
warning.
lThe BCU receives an input from the SLABS ECU relating to the raise/ lower command from the remote handset.

+ REAR SUSPENSION, DESCRIPTION AND OPERATION, Description - SLS.
Hill descent control
The BCU provides an output signal to the SLABS ECU for automatic transmission in neutral for HDC control. The
BCU checks the status of the ignition and 'gearbox state' inputs and provides a 'Neutral selected' output. If the ignition
is on and 'gearbox state' is Neutral, the 'Neutral selected' output is on, otherwise 'Neutral selected' is off.

+ BRAKES, DESCRIPTION AND OPERATION, Description.
Heated screens
The Heated Front Screen (HFS) is fitted for some market destinations and is operated from a non-latching switch
located on the instrument pack cowl. The BCU will only allow the heated front screen to operate when the engine is
running and controls the time-out period for switching the circuit off.
The heated front screen operation can also be controlled from the Automatic Temperature Control (ATC) ECU on
vehicles fitted with air conditioning.
The heated rear window will only function when the engine is running, and is operated by a non-latching switch on the
instrument pack cowl. The heated rear window can also be operated by the ATC ECU on vehicles fitted with air
conditioning.
Interior courtesy lamps
The BCU controls the operation of the interior courtesy lamps. The courtesy lamps are situated in the front, mid and
rear areas of the headlining.
Fuel flap actuator
The BCU provides an earth path to the fuel flap release solenoid to allow the fuel filler flap to be opened. This is only
allowed if the alarm system is not set and all other conditions have been satisfied. The fuel flap release switch is
located in the fascia switch pack and it receives a voltage supply from the passenger compartment fuse box.
Audible warnings
The BCU can request the instrument pack to generate an audible warning in response to conditions it has detected
and which need to be drawn to the driver's attention. One of six different audible warnings can be requested by the
BCU.
Sound request number Sound functions Priority (1 = lowest, 6 = highest)
0Off 1
1 Seat belt warning 6
2 Key-in warning 3
3 SLABS/ HDC warning 4
4 Transfer box in neutral warning 5
5 Lights on warning 2

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.

IN CAR ENTERTAINMENT
DESCRIPTION AND OPERATION 86-6-11
If one headphone amplifier unit has control of the tape player, CD or radio, the other headphone amplifier will be able
to listen and be able to change tape tracks or radio bands. Other buttons allow a search seek function of radio band
or compact disk track, reversal of the tape, radio station and volume adjustment depending on the current operating
mode. If one radio headphone amplifier has control of the radio, tape or CD autochanger the other radio headphone
amplifier is able to change the track or radio band selected. A headphone socket with a glow ring is located on the
control panel. When a headphone is turned on , a 'headphone-module active' signal is sent to the radio cassette
player. The design incorporates panel illumination and a glow-ring to locate the socket in low light conditions. To
control the audio output from the radio headphone amplifiers, signals are sent to and received from the radio cassette
player.
Automatic volume control (High line system only)
An automatic base and treble volume control feature compensates for increases in interior road/transmission noise.
A road speed signal is monitored by the power amplifier, the signal is supplied by the SLABS ECU.

+ BRAKES, DESCRIPTION AND OPERATION, Description.The power amplifier boosts the levels of base
and treble as road speed increases. This system ensures that the apparent volume of sound remains constant and is
not affected by increases in the background noise in the vehicle.
Speakers
Some vehicles will not have all the speakers, the type and location of speakers fitted depends on the trim level and
ICE options specified for the vehicle.
A-post speakers LH/RH (if fitted)
The A-post speakers are located in the A-post trim on each side of the windscreen, and are each protected by a metal
grille. The speakers are held from the rear by a bayonet clip that clamps the speaker on to the A-post trim. The A-post
speakers are a high range type and have a power rating of:
lMid line system A-post speakers have a power rating of 15 watts and an impedance of 4
Ω.
lHigh line system A-post speakers have a power rating of 30 watts and an impedance of 4
Ω.
Upper front and rear door speakers LH/RH (high line system only)
The upper door speakers are located in the upper door trim, the speaker is protected by an integral metal grille. The
speaker is held in by a threaded ring that clamps the speaker from the rear onto the door trim. The upper door speaker
is a mid-range type and has a power rating of 30 watts and an impedance of 4
Ω.
Lower front door speakers LH/RH
The lower front door speaker is located in the front end of the lower (pocket) trim and is secured by three self tapping
screws. The speaker is protected by a clip on circular metal grille. The type of lower front door speakers fitted depends
on trim level and market:
lThe base and mid line systems are fitted with full-range door speakers with a power rating of 15 watts and an
impedance of 4
Ω
lThe high line system is fitted with a low-range door speaker with a power rating of 30 watts and an impedance
of 4
Ω.
Lower rear door speaker LH/RH
The lower rear door speaker is located in the lower door trim and is secured by three self tapping screws. The speaker
is protected by a clip on metal grille. The type of lower rear door speaker fitted depends on trim level and market:
lThe base and mid line systems are fitted with full-range door speakers with a power rating of 15 watts and an
impedance of 4
Ω
lThe high line system is fitted with a low-range door speaker with a power rating of 30 watts and an impedance
of 4
Ω.
Low range tail door speakers (high line system only)
The low range tail door speaker are located in a plastic casing in the lower door trim. Each of the two speakers is
secured to the casing with four self tapping screws. The casing is secured to the lower door structure with eight bolts.
The tail door trim surrounds the casing, the front of the casing is covered by a metal grill that is secured with six
screws. The low range tail door speakers have a power rating of 30 watts and has an impedance of 4
Ω.

HARNESSES
REPAIRS 86-7-27
89.Disconnect 3 multiplugs from RH rear door
harness.
90.Remove 2 nuts securing 2 earth headers to
rear centre console tunnel.
91.Remove earth headers from centre console.
92.Disconnect multiplug from CD player.
93.Remove 5 clips and 2 retainers securing
harness to floor. 94.Disconnect 3 multiplugs from LH rear door
harness.
95.Withdraw harness to interior.
96.Manoeuvre harness over steering column
support bracket.
97.With assistance remove main harness.
Refit
1.With assistance position main harness to body
and manoeuvre over steering column support
bracket.
2.Lay harness in position and secure to floor
clips and retainers.
3.Connect LH and RH rear door multiplugs.
4.Connect CD player multiplug.
5.Position centre console earth headers and
secure with nuts.
6.Fit rear carpet.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Carpet - rear.
7.Connect DCU multiplug.
8.Connect Lucar to handbrake switch.
9.Fit and tighten nuts securing harness to
transmission tunnel.
10.Secure harness to pedal box.
11.Position footwell earth header and secure with
nut.
12.Feed RH side of harness into engine bay.
13.Position carpet.
14.Connect wiper motor multiplug, position
mechanism and secure with nuts and bolts.
15.Connect ECM multiplug.
16.Position RH lower 'A' post earth header and
secure with nut, connect cruise control
multiplug.
17.Connect RH front door and RH side body
harness multiplugs.

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.