reset LAND ROVER DISCOVERY 2002 User Guide

REAR SUSPENSION
DESCRIPTION AND OPERATION 64-17
SLABS ECU
1SLABS ECU
2Bracket
3BCU (Ref. only)
4ACE ECU (Ref. only)
5Attachment nuts
The SLABS ECU is mounted on a bracket behind the passenger glove box and is identified from the other ECU's by
its five connectors. The five connectors are located on the lower face of the ECU and mate with five connectors from
the main harness. The twelve, six and eighteen pin connectors are used to supply inputs and outputs to and from the
ECU. The remaining connectors are used for the ABS operation.

+ BRAKES, DESCRIPTION AND OPERATION, Description.
The SLABS ECU receives a continuous battery supply from fuse 11 in the engine compartment fusebox. An ignition
'ON' signal is supplied from the ignition switch via fuse 28 in the passenger compartment fusebox. The ECU has the
ability to control when it requires power and is not reliant on the ignition signal for it to power up.
The ECU incorporates a counter which times the operation of the SLS system and prevents the compressor
exceeding its duty cycle. The ECU can remain powered for up to 1.5 hours after ignition off is sensed to allow the
counter to continue running to avoid an ignition cycle resetting the counter.
Opening any of the doors will power up the ECU, irrespective of ignition switch position. The door open signal is
sensed by the door switch completing an earth path which is sensed by the ECU. The ECU cannot differentiate
between any of the doors. The door open signal powers the ECU for up to 30 minutes to allow the vehicle to re-level
when a load is removed or passengers leave the vehicle.

REAR SUSPENSION
64-22 DESCRIPTION AND OPERATION
Pressing the lower button will signal the SLABS ECU, via the RF receiver and the BCU, to energise the exhaust valve
and air control valves. The SLS will lower up to 60 mm (2.36 in) below normal ride height if the button is held. If the
button is released the SLS will stop at that point.
Pressing the raise button will signal the SLABS ECU, via the RF receiver and the BCU, to start the compressor and
energise the exhaust valve and air control valves. The SLS will raise to normal ride height if the button is held. If the
button is released the SLS will stop at that point.
When raising or lowering the SLS using the remote handset, the SLS warning lamp will flash and the audible warning
will sound when the system is operating. When the SLS is fully lowered the warning lamp will stay illuminated. The
SLS will reset to normal ride height if the vehicle speed exceeds 3 mph (5 km/h) for 10 seconds when the SLS is
lowered.
Transportation mode
Transportation mode must be used when the vehicle is transported on a trailer and secured by the chassis. The
transportation mode can only be enabled and disabled with TestBook.
The transportation mode lowers the rear suspension onto the bump stops with the engine not running. When the
suspension is in transportation mode, the SLS warning lamp is continuously illuminated when the ignition is in position
II.
When the engine is started in transportation mode, the SLS system will raise the rear suspension until a gap of 25
mm (1 in.) exists between the bump stop and the axle. The SLS warning lamp will flash continuously while the SLS
system is raising the suspension. When the gap between the bump stop and the axle is achieved, the warning lamp
will illuminate continuously.
When TestBook is used to disable the transportation mode, the rear suspension will raise to normal ride height when
the engine is running.

BRAKES
70-22 DESCRIPTION AND OPERATION
Minimum target speed
The minimum target speed depends on which gear is engaged. Reduced minimum target speeds are employed for
some gears if rough terrain or sharp bends are encountered while already travelling at the normal minimum target
speed. If loss of traction makes it impossible to maintain the minimum target speed, the SLABS ECU temporarily
increases the minimum target speed to maintain stability, then restores the normal minimum target speed when
traction improves.
HDC minimum target speeds
Fade out
To provide a safe transition from active braking to brakes off, the SLABS ECU invokes a fade out strategy if it detects
any of the following during active braking:
lA system fault.
lThe conditions for HDC are no longer being met.
lPossible brake overheat.
The fade out strategy increases the target speed at a low constant acceleration rate, independent of actual throttle
position. This results in the braking effort being gradually reduced and then discontinued. The SLABS ECU operates
warning indications during fade out that are dependent on the cause.
Fade out warning indications
Clutch disengagement/neutral selection
During active braking, if the SLABS ECU detects the clutch is disengaged or neutral is selected, it flashes the HDC
information warning lamp and sounds the audible warning continuously to indicate that conditions for HDC are no
longer being met. Initially, the SLABS ECU also fixes the target speed to the applicable minimum target speed, but if
the condition continues for approximately 60 seconds the SLABS ECU invokes fade out.
Brake overheat prevention
To prevent the brakes overheating, the SLABS ECU monitors the amount of active braking employed and, from this,
estimates brake temperature. If the SLABS ECU estimates the brake temperature has exceeded a preset limit, it
flashes the HDC fault warning lamp and sounds the audible warning continuously, to indicate that HDC should be
deselected to allow the brakes to cool. If active braking continues and the SLABS ECU estimates that brake
temperature has increased to an unacceptable level, fade out is employed and HDC is disabled. After fade out, the
audible warning is discontinued but the HDC fault warning lamp continues to flash, while HDC is selected, until the
SLABS ECU estimates brake temperature to be at an acceptable level. This calculation continues even if the ignition
is turned off, so turning the ignition off and back on will not reduce the disabled time. When the SLABS ECU estimates
the brake temperature to be acceptable, it extinguishes the HDC fault warning lamp and illuminates the HDC
information warning lamp to indicate that HDC is re-enabled. The disabled time is dependent on vehicle speed; typical
times at constant vehicle speeds are as follows:
Gear Speed, mph (km/h)
Manual gearbox Automatic gearbox
Normal Reduced Normal Reduced
1 4.4 (7.0) 4.4 (7.0) 4.4 (7.0) 4.4 (7.0)
2 5.2 (8.3) 4.4 (7.0) 4.4 (7.0) 4.4 (7.0)
3 6.0 (9.6) 4.4 (7.0) 7.5 (12.0) 6.0 (9.6)
4 7.5 (12.0) 6.0 (9.6) 7.5 (12.0) 6.0 (9.6)
5 8.8 (14.0) 7.0 (11.2) - -
Reverse 3.5 (5.6) 3.5 (5.6) 3.5 (5.6) 3.5 (5.6)
Neutral or clutch
disengaged8.8 (14.0) Last off road speed 4.4 (7.0) 4.4 (7.0)
Cause Warning indication
HDC fault warning lamp HDC information
warning lampAudible warning
Fault detected On Flashes Continuous
HDC conditions not met Off Flashes Continuous
Brake overheat prevention Flashes Off Continuous

BRAKES
REPAIRS 70-37
Switch - brake light
$% 70.35.42
The brake switch is set automatically during fitment.
If the setting is disturbed, the switch can be reset by
depressing the brake pedal and pulling the plunger
out of the switch body, until it contacts the pedal.
Remove
1.Remove 3 fasteners and move drivers side
lower closing panel aside.
2.Disconnect multiplug from brake light switch.
3.Remove brake light switch from pedal bracket.
Refit
1.Engage switch fully into pedal bracket location
and connect multiplug.
2.Position lower closing panel and secure with
fasteners.
Brake pads - front
$% 70.40.02
WARNING: Brake pads must be renewed in axle
sets only, otherwise braking efficiency may be
impaired.
Remove
1.Raise front of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Remove road wheel(s).
3.Remove lower guide pin bolt from caliper and
pivot caliper housing upwards.
4.Remove 2 brake pads from caliper carrier.
Shims are part of the brake pads.
Refit
1.Rotate disc by hand and scrape all scale and
rust from around edge of disc.
2.Scrape rust from pad locating surfaces on
caliper.
3.Clean dust from calipers using brake cleaning
fluid.
WARNING: Do not use compressed air to
clean brake components. Dust from friction
materials can be harmful if inhaled.

SEATS
DESCRIPTION AND OPERATION 76-5-5
Seat switch pack
Each seat switch pack contains two switches representing the seat cushion and the seat squab. The switches provide
the following adjustments:
lSeat fore/ aft.
lCushion front up/ down.
lCushion rear up/ down.
lSquab fore/ aft.
lLumbar inflate.
lLumbar deflate.
The voltage supply to the seat switch pack is from the 40A fuse in the satellite fuse box. A pair of switches controls
the operation of each seat motor, the lumbar pump and the lumbar deflate relay.
Seat fore/ aft motor
The seat fore/ aft 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.

SEATS
76-5-6 DESCRIPTION AND OPERATION
Two pins within the seat switch pack control the seat fore/ aft 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 fore/ aft motor
The squab fore/ aft 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). If a problem occurs with the lumbar bladder, e.g. a rupture, the whole lumbar system must be
replaced. The components are not serviceable.
Power comes from the seat switch pack through a 3A fuse in the satellite fuse box. The lumbar pump and the lumbar
deflate solenoid share an earth.
Lumbar deflate solenoid
The lumbar deflate solenoid vents the lumbar bladder to atmosphere to allow air to evacuate the bladder. The average
time to evacuate the bladder with a load of 25 kg (55 lb) is 9 seconds.
Power comes from the seat switch pack through a 3A fuse in the satellite fuse box. The lumbar deflate solenoid and
the lumbar pump share an earth.

AIR CONDITIONING
82-18DESCRIPTION AND OPERATION
Operation
General
While the system is on, the ATC ECU operates the refrigerant system and the inlet air, blower speed, air temperature
and air distribution functions to produce the conditions requested on the control panel. When the system is first
switched on, the ATC ECU resumes the control outputs in use when the system was last switched off. If conditions
have changed, or a different mode is selected to switch the system on, the control outputs are then changed to
produce the required new settings.
The system operates in automatic, economy and defrost modes, with manual overrides of the inlet air source, blower
speed and air distribution. The air temperature is automatically controlled in all operating modes.
In the automatic mode, the ATC ECU operates the system to warm-up or cool down the cabin to establish and
maintain the temperature selections on the control panel, while directing the air to those outlets most comfortable for
the occupant(s). If a difference between the LH and RH temperature selections causes a conflict of the required inlet
air source, blower speed or air distribution settings, priority is given to achieving the temperature requested on the
driver's side of the control panel.
The ATC ECU enters the economy mode when the refrigerant compressor is selected off while the system is in the
automatic mode, which reduces the load on the engine. Economy mode operation is similar to the automatic mode,
but without the ability to cool the cabin if the ambient temperature is higher than the temperature selections made on
the control panel, or to dehumidify the air in the cabin.
In the defrost mode, the ATC ECU sets the inlet air source to fresh air, the blower to maximum speed, the air
distribution to windscreen and side windows, and outputs signals to the BCU to operate the rear window heater and
(where fitted) the windscreen heater. The BCU starts or, if the heaters are already on, resets the heater timers and
energises the rear window and windscreen heaters for a complete on cycle.
Air temperature control
To determine the amount of heat or cooling required by the cabin, the ATC ECU uses the sensor inputs and the
temperatures selected on the control panel to calculate target air outlet temperatures for the driver's and the front
passenger's side of the heater assembly. The ATC ECU then signals the servo motors controlling the respective blend
flaps in the heater assembly to move to the flaps to the appropriate position. The target temperatures are constantly
updated and, in the automatic mode, also used in further calculations to determine the inlet air source, the blower
speed and the air distribution.
Inlet air control
The inlet air source is automatically controlled while the system is off or on. While the system is on, the inlet air source
can also be manually controlled to give timed recirculated air or latched recirculated air.
While the system is off, the ATC ECU uses vehicle speed to determine the inlet air source. With the vehicle at rest,
the inlet air source is set to recirculated air. When vehicle speed reaches 17.5 mph (28 km/h), the inlet air source
changes to fresh air. The inlet air source then remains at fresh air until the vehicle speed decreases to 5 mph (8 km/
h), when it returns to recirculated air.
While the system is on, the ATC ECU uses the LH and RH temperature selections, vehicle speed, ambient air
temperature and coolant temperature to determine the inlet air source. In the automatic mode:
lIf one temperature selection is set to LO and one is set to a specific temperature or HI, the inlet air is set to
recirculated air.
lIf one temperature selection is set to HI and one is set to a specific temperature or HI, the inlet air is set to fresh
air.
lWhen specific LH and RH temperature selections are set, the inlet air source remains at fresh air except when
the air distribution function is set to face level only or face level and footwell outlets. If the air distribution function
is set to face level only or face level and footwell outlets, at 56 mph (90 km/h) the inlet air source changes to
recirculated air (to exclude ram effect, which becomes excessive at speed). When the vehicle speed decreases
to 37.5 mph (60 km/h), the inlet air source returns to fresh air.

WIPERS AND WASHERS
84-16 DESCRIPTION AND OPERATION
Operation
Front intermittent wipe variable delay
The front intermittent wipe variable delay operation allows the driver to adjust the interval between wipes to suit local
conditions. Front variable delay operation activates when the following conditions are met:
lIgnition switch in position I or II.
lFront wash/ wipe switch is in the intermittent position.
The BCU receives the front intermittent wipe signal from the front wash/ wipe switch. The BCU receives a separate
signal from the variable delay switch, determines the delay interval from the front wash/ wipe switch position and
passes it on to the IDM. The IDM energises the front wiper relay to activate the front wiper motor.
If the delay duration is decreased during front variable delay operation, the wipers immediately operate once and then
the delay cycle is reset to the new duration.
If the delay duration is increased during front variable delay operation, the delay cycle is automatically increased by
the BCU.
Front low speed
Front low-speed operation activates when the following conditions are met:
lIgnition switch is in position I or II.
lFront wipe/ wash switch is in low speed position.
Selecting low-speed on the front wash/ wipe switch signals the IDM to energises the front wiper relay, which provides
power to the front wiper motor assembly.
Front high speed
Front high-speed operation activates when the following conditions are met:
lIgnition switch is in position I or II.
lFront wipe/ wash switch is in high speed position.
Selecting high speed on the front wash/ wipe switch allows power to flow from the switch directly to the wiper motor.
The high-speed input goes to a set of brushes in the wiper motor that are closer together than the low speed brushes.
These brushes allow the motor to run at a faster speed but with less torque.
Front washer
Front washer operation will only activate when the following conditions are met:
lIgnition switch is in position I or II.
lFront washer switch operated.
Flicking the front washer switch energises the front washer pump motor for 0.4 second. Holding the front washer
switch for longer than 0.4 second allows the front washer pump motor to run as long as the switch is held.
There are two front washer configurations. If the vehicle is fitted with programme wash/ wipe, and the front washer
pump motor is active for more than 0.5 second, the front wipers operate at low speed. The wipers continue to operate
for 4 seconds after the washer switch is released. In some markets, the driver must activate the front wipers after a
front washer operation.
The front washer operation has a higher priority than the variable delay operation. This means that if intermittent wipe
is active when a front washer operation is initiated, the wash cycle executes and the intermittent wipe is re-instated
at the end of the wash operation.

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.

WIPERS AND WASHERS
84-18 DESCRIPTION AND OPERATION
Rear wipe
Rear wipe operation will only activate when the following conditions are met:
lIgnition switch is in position II.
lRear wipe switch is operated.
Operating the rear wiper switch provides an earth input to the BCU. The BCU tells the IDM to activate the rear wiper
relay, which provides battery voltage to the wiper motor through the normally closed contacts of the park switch.
Rear wash
Rear wash will only operate when the following conditions are met:
lIgnition switch is in position II.
lRear wash switch operated.
Operating the rear washer switch for longer than 0.4 second allows the rear washer pump motor and rear wipers to
run as long as the switch is held. The wipers run for 4 seconds after the rear washer switch is released. Flicking the
rear washer switch energises the rear washer pump motor for 0.4 second.
The rear washer operation has a higher priority than the intermittent wipe operation. If the intermittent wipe is active
when a rear washer operation is initiated, the wash cycle executes and the intermittent wipe is re-instated at the end
of the washer operation.
Wiper park switch
The park switch allows the wipers to come to rest in the park position when the wipe switch is turned off in mid-wipe.
The park switch consists of a positive and a negative contact. These two contacts are described as closed at park
and closed when operating. When the wipers first start, the park switch is in the closed at park position. A relay
controls battery voltage to the motor. Battery voltage passes through this relay contact to move the wiper motor from
the park position.
When the motor moves, the park switch moves to the closed when operating position. Battery voltage to this relay
contact is direct from fuse 19. Battery voltage passes through this contact to keep the wiper motor running. The wiper
motor operates for one complete revolution until the park switch moves to the closed at park position again.
Switching off the wipers removes battery voltage from the closed at park contact. When the wipers reach the closed
at park switch an earth is applied and the motor stops abruptly.
Headlamp power wash
Headlamp power wash activates when the following conditions are met:
lIgnition switch in position II.
lHeadlamps switched on.
lFront wash switch operated.
lBCU counter allows headlamp power wash.
Operating the front washer switch with the headlamps switched on energises the IDM, supplying a voltage to the
headlamp powerwash relay, which operates the headlamp powerwash pump and increments a counter within the
BCU. This counter prevents the headlamp powerwash pump from operating every time the front washer switch is
activated. Headlamp powerwash is only operational every third front wash cycle, providing the headlamps are on.
The counter resets when the ignition switch is turned off.
When the BCU permits headlamp power wash operation, the pump motor operates only for 0.5 second.