2002 LAND ROVER DISCOVERY ECO mode

AIR CONDITIONING
DESCRIPTION AND OPERATION 82-19
In the defrost mode, the inlet air source is set to fresh air except at low ambient air and coolant temperatures. If, within
5 minutes of the ignition being switched on, the vehicle speed is less than 5 mph (8 km/h) while the external air
temperature is
−16 °C (3 °F) or less and the heater coolant temperature is −10 °C (14 °F) or less, then the inlet air
source is automatically set to the timed recirculated air mode. The timed recirculated air mode is cancelled
immediately the vehicle speed reaches 8 km/h or more .
Timed recirculated air
The timed recirculated air mode sets the inlet air source to recirculated air for 5
± 1 minutes, after which it automatically
reverts to fresh air. Timed recirculated air can be manually selected:
lIn the automatic mode, by pressing the fresh/recirculated air switch for 1.5 seconds or more; the audible warning
sounds twice.
lIn the economy or defrost modes, by pressing the fresh/recirculated air switch for less than 1.5 seconds; the
audible warning sounds once.
Latched recirculated air
The inlet air source can be latched to recirculated air:
lIn the automatic mode, by pressing the fresh/recirculated air switch for less than 1.5 seconds; the audible
warning sounds once.
lIn the economy or defrost modes, by pressing the fresh/recirculated air switch for 1.5 seconds or more; the
audible warning sounds twice.
Blower control
The ATC ECU operates a blower relay, power transistor and power relay to run the blower at one of 31 stepped
speeds. All speed steps are available in the automatic modes of blower control. In the manual mode, speed steps 3,
10, 16, 22 and 31 are used to provide slow, three intermediate and fast blower speeds. The ATC ECU energises the
blower relay and modulates the power transistor to operate the blower for speed steps 1 to 30. For speed step 31, the
ATC ECU energises the power relay, which switches the earth side of the blower motor direct to earth, bypassing the
power transistor.
In the automatic, economy and defrost modes, blower speed is corrected for vehicle speed to compensate for the
increase in ram effect on the inlet air as the vehicle speed increases. Correction begins at approximately 50 km/h,
when blower speed is progressively decreased as vehicle speed increases, until a maximum decrease of 13 steps
occurs at 123 km/h. Similarly, blower speed increases as vehicle speed decreases down to approximately 50 km/h.
In the automatic and economy modes, if the LH or RH temperature is set to LO or HI, the blower runs at maximum
speed with correction only for vehicle speed. If both the LH and RH outlet air temperatures are set to a specific
temperature, blower speed corrections are added to compensate for the heater coolant temperature, external air
temperature, and the solar load acting on the vehicle:
lDuring warm-up, the blower speed is set to 3 while the heater coolant temperature is below approximately 20
°C
(68
°F). From approximately 20 °C (68 °F), the blower speed is progressively increased as the coolant
temperature increases, until maximum speed is set at approximately 50
°C (122 °F).
lDuring cool down, blower speed is set to 3, for 5 seconds after the system is switched on. Over the following 6
seconds, the blower speed is progressively increased up to maximum speed.
lAs the temperature in the cabin approaches the selected temperatures, blower speed is progressively reduced
until, once the selected temperatures have been established, blower speed stabilises at approximately 6.
lSolar heating correction is employed when air distribution is set to face level or to face and footwells. The
correction progressively increases the blower speed, up to a maximum of 9 steps, with increasing values of solar
heating.

AIR CONDITIONING
82-20DESCRIPTION AND OPERATION
Air distribution control
To control the air distribution within the cabin the ATC ECU signals the servo motor controlling the distribution flaps
in the heater assembly to move to the flaps to the appropriate position.
In the automatic and economy modes, if the LH or RH temperature selections are set to LO or HI, air distribution is
fixed as follows:
lIf one is set to LO and one is set to a specific temperature, to face level only.
lIf one is set to HI and one is set to a specific temperature, to footwells only.
lIf one is set to LO and one is set to HI, to face level and footwells.
When specific LH and RH temperature selections are set, air distribution is determined from the target air outlet
temperatures. For higher target air outlet temperatures, air distribution is set to footwells only. For lower target air
outlet temperatures, air distribution is set to face level only. For intermediate target air outlet temperatures, air
distribution is set to face level and footwells. When the air distribution is set to face level and footwells, the ATC ECU
varies the bias between the footwells and the face level outlets, in three stages, to provide a gradual transition of air
distribution from footwells only to face level only. The three stages of bias are also employed when the air distribution
is manually selected to face level and footwells.
During warm-up, the air distribution changes to face level and footwells for a period, then reverts to footwells only.
The period of air distribution at face level and footwells can be cancelled by pressing and holding the on/off and defrost
mode switches, then turning the ignition switch from off to on. Pressing and holding the AUTO and defrost switches,
then turning the ignition switch from off to on, restores the period of air distribution at face level and footwells.
Compressor control
To engage the compressor clutch, the ATC ECU outputs a compressor clutch request to the ECM, which then
energises the A/C compressor clutch relay. Compressor operation is governed by the evaporator outlet air
temperature, at one of two settings, dependent on the amount of cooling required. When more cooling is required, the
compressor clutch request is output if evaporator outlet air temperature increases to 4
°C (39 °F) and cancelled when
it decreases to 3
°C (37 °F). When less cooling is required, the compressor clutch request is output if evaporator outlet
air temperature increases to 11
°C (52 °F) and cancelled when it decreases to 10 °C (50 °F).
Engine cooling fan control
While the A/C system is on, operation of the electric engine cooling fan, to assist refrigerant condenser operation, is
determined by a combination of vehicle speed and external air temperature. When cooling fan operation is required,
the ATC ECU outputs a cooling fan request to the ECM, which then energises the cooling fan relay. The cooling fan
request is output if vehicle speed is 80 km/h or less while the external air temperature is 28
°C (82 °F) or more. The
request is cancelled, and the cooling fan switched off, if either the vehicle speed increases to 100 km/h, or the external
air temperature decreases to 25
°C (77 °F).
Default settings
If the battery power supply to the ATC ECU is disrupted for any reason, e.g. battery disconnected, the system reverts
to default settings when the battery power supply is restored. Default settings are:
lTemperature indications in
°C (in some markets a conversion connector is fitted to the ATC ECU to change the
default temperature scale to
°F).
lLH and RH outlet temperatures of 22
°C (72 °F).
laudible warning switched on.
lWarm-up air distribution (to face level and footwells) function switched on.
lIf the system is first switched on using the A/C on/off switch, the automatic mode is engaged, regardless of the
settings in use when the battery was disconnected.

AIR CONDITIONING
82-42REPAIRS
13.Remove covering from TX valve, release 2
clips securing TX valve to pipe.
14.Release 2 unions securing TX valve, remove
TX valve, remove and discard 'O' rings.
15.Release pipe union, remove pipe and discard
'O' ring.
Refit
1.Using a new 'O' ring, position pipe to
evaporator and tighten union.
2.Using new 'O' rings, position TX valve. Connect
pressure pipe union and tighten to 22 Nm (16
lbf. ft). Connect evaporator pipe and tighten to
32 Nm (24 lbf.ft).
3.Position TX valve sensor to pipe and secure
with clips.
4.Fit sensor covering.
5.Fit evaporator thermistor.
6.Fit evaporator assembly.
7.Fit insulation to evaporator casing and fit
casing.
8.Secure spring clips.
9.Fit and tighten casing screws.
10.Fit heater matrix, ensuring matrix temperature
is correctly positioned.
11.Fit coolant pipe saddle, fit and tighten screws
securing saddle and pipe bracket.
12.Fit and tighten temperature servo screws.
13.Connect multiplug to evaporator thermistor.
14.Clean any bulk head seal from casing.
15.Fit bulkhead and evaporator pipe seals.
16.Fit heater assembly.

+ HEATING AND VENTILATION,
REPAIRS, Heater assembly - models with
air conditioning.
Expansion valve - (TXV) - rear
$% 82.26.01
Remove
1.Depressurise air conditioning system.

+ AIR CONDITIONING, REFRIGERANT
RECOVERY, RECYCLING AND
RECHARGING, Refrigerant recovery,
recycling and recharging.
2.Remove rear lower trim casing.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - side - loadspace.
3.Remove 5 bolts securing seat support bracket
and remove bracket.
4.Release insulation from TXV pipe unions and
sensor.
5.Remove clip securing sensor to pipe and
release sensor.

AIR CONDITIONING
82-44REPAIRS
6.Remove 6 screws and 4 clips securing main
casing and remove top half of casing.
7.Loosen and release evaporator pipes unions,
release pipes and remove evaporator.
8.Remove and discard evaporator pipe 'O' rings.
Refit
1.Lubricate new 'O' rings with clean refrigerant oil
and fit to evaporator pipes
2.Position evaporator, connect pipes and tighten
unions.
3.Position main casing and secure with clips and
screws.
4.Position lower part of casing and secure with
screws.
5.Fit ducting seal
6.Secure relay to support bracket.
7.Fit insulation to TXV.
8.Fit evaporator assembly.

+ AIR CONDITIONING, REPAIRS,
Evaporator and motor assembly - rear.
Evaporator and motor assembly - rear
$% 82.26.21
Remove
1.Depressurise air conditioning system.

+ AIR CONDITIONING, REFRIGERANT
RECOVERY, RECYCLING AND
RECHARGING, Refrigerant recovery,
recycling and recharging.
2. V8 models: Remove 4 clips securing rear
exhaust heat shield and remove heat shield.
3.Remove 2 bolts securing high and low
pressure pipes, release pipes and discard 'O'
rings.
CAUTION: Always fit plugs to open
connections to prevent contamination.
4.Remove 2 bolts securing grommet flange to
body and remove flange.
5.Remove LH rear lower trim casing.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - side - loadspace.
6.Remove 5 bolts securing seat support bracket
and remove bracket.

AIR CONDITIONING
REPAIRS 82-45
7.Disconnect A/C harness multiplugs from body
harness.
8.Remove 2 clips securing ducting to A/C
assembly and release ducting. 9.Remove 4 bolts securing evaporator assembly
and remove assembly.
Refit
1.Position evaporator assembly to body fit bolts
and tighten to 16 Nm (12 lbf.ft).
2.Position ducting to evaporator assembly and
secure with clips.
3.Connect harness multiplugs.
4.Position seat support bracket, fit bolts and
tighten to 24 Nm (18 lbf.ft).
5.Fit LH rear lower trim casing.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - side - loadspace.
6.Position grommet flange and tighten bolts.
7.Lubricate new 'O' rings with clean refrigerant oil
and fit to high and low pressure pipes.
8.Position high and low pressure pipes, fit bolts
and tighten to 10 Nm (7 lbf.ft).
9. V8 models: Position exhaust heat shield and
secure with clips.
10.Repressurise air conditioning system.

+ AIR CONDITIONING, REFRIGERANT
RECOVERY, RECYCLING AND
RECHARGING, Refrigerant recovery,
recycling and recharging.

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.

LIGHTING
86-2-2 ADJUSTMENTS
Headlamps beam alignment - from 03MY
$% 86.40.17
Check
1.Ensure vehicle is unladen and tyres are set at
the correct pressures.
2. Models with SLS: Ensure vehicle is at the
standard ride height.
3. Models without SLS: Set headlamp leveling
switch to zero.
4.Align beam setting equipment to headlamp.
5.Switch on headlamps. Headlamp setting 1.2%
below horizontal and parallel.
6.Align beam setting equipment to second
headlamp and repeat the check.
Adjust
1.Using a flat blade screwdriver rotate the
headlamp adjusters until correct alignment is
achieved
2.Rotate inboard adjuster for verticle alignment.
3.Rotate outboard adjuster for horizontal
alignment.
4.Adjust 2nd headlamp as detailed above.
5.Switch off headlamps and remove beam setting
equipment.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-1
BODY CONTROL UNIT DESCRIPTION AND OPERAT ION
Description
General
The Body Control Unit (BCU) is located behind the passenger glovebox and is connected to the main harness by four
connectors on its bottom edge and an additional connector located on the side of the BCU casing. Mounting the BCU
behind the fascia makes it reasonably inaccessible for intruders to disable the anti-theft system.
The BCU uses solid-state microprocessor control to perform logical operations and timing functions for a variety of
the vehicle's electrically operated systems, these include:
lDoor locking.
lAnti-theft alarm and immobilisation system.
lExterior lighting including direction indicators and hazard warning lamps.
lCourtesy lighting.
lWipers and washers.
lElectric windows and sunroof.
lHeated windows.
The BCU also communicates with several other electronically controlled systems such as the EAT ECU and SLABS
ECU and also has a datalink between the Intelligent Driver Module (IDM) and the instrument pack. The datalink is a
low speed bus capable of transmitting and receiving messages at a data rate of 10,400 bits per second. Additional
inputs and outputs to peripheral devices are included which are necessary for determining vehicle status for particular
logical operations e.g. crank, ignition key inserted, fuel flap enable etc.
The BCU receives its power supply from the engine compartment fuse box, and is protected by a 10 A fuse.
The BCU communicates with the IDM to provide the control signals to perform power switching operations in
conjunction with dedicated relays.
IDM
The IDM is integrated into the passenger compartment fuse box, which is mounted behind the fascia below the
steering column. There are no harnesses between the fuse box and the IDM. The IDM performs the power switching
operations for several of the vehicle's electrical systems.
The IDM communicates with the BCU and the instrument pack via a serial interface. If the BCU or the IDM is replaced,
the communications link between the two units has to be re-established. This can be done either by switching on the
ignition and leaving it on for five minutes, or by using TestBook. The vehicle immobilisation will remain active until the
communications link between the BCU and IDM has been re-established.
Transit mode
To prevent excessive battery drain during transit to overseas markets, the vehicle is placed in a transit mode. The
following functions are disabled when the vehicle is in transit mode:
lVolumetric sensors.
lPassive immobilisation.
lImmobilisation of the vehicle by use of door lock.
lIgnition key interlock.
lElectric seat enable time-out with driver's door open.