2002 LAND ROVER DISCOVERY check engine light

ENGINE MANAGEMENT SYSTEM - V8
18-2-54 DESCRIPTION AND OPERATION

Drive cycle C:
1Switch ignition on for 30 seconds.
2Ensure engine coolant temperature is less than 60
°C (140°F).
3Start the engine and allow to idle for 2 minutes.
4Perform 2 light accelerations (0 to 35 mph (0 to 60 km/h) with light pedal pressure).
5Perform 2 medium accelerations (0 to 45 mph (0 to 70 km/h) with moderate pedal pressure).
6Perform 2 hard accelerations (0 to 55 mph (0 to 90 km/h) with heavy pedal pressure).
7Cruise at 60 mph (100 km/h) for 8 minutes.
8Cruise at 50 mph (80 km/h) for 3 minutes.
9Allow engine to idle for 3 minutes.
10Connect TestBook and with the engine still running, check for fault codes.
NOTE: The following areas have an associated readiness test which must be flagged as complete, before a problem
resolution can be verified:
lcatalytic converter fault;
lEvaporative loss system fault;
lHO
2 sensor fault;
lHO
2 sensor heater fault.
When carrying out a drive cycle C to determine a fault in any of the above areas, select the readiness test icon to
verify that the test has been flagged as complete.

Drive cycle D:
1Switch ignition on for 30 seconds.
2Ensure engine coolant temperature is less than 35
°C (95°F).
3Start the engine and allow to idle for 2 minutes.
4Perform 2 light accelerations (0 to 35 mph (0 to 60 km/h) with light pedal pressure).
5Perform 2 medium accelerations (0 to 45 mph (0 to 70 km/h) with moderate pedal pressure).
6Perform 2 hard accelerations (0 to 55 mph (0 to 90 km/h) with heavy pedal pressure).
7Cruise at 60 mph (100 km/h) for 5 minutes.
8Cruise at 50 mph (80 km/h) for 5 minutes.
9Cruise at 35 mph (60 km/h) for 5 minutes.
10Allow engine to idle for 2 minutes.
11Connect TestBook and check for fault codes.

Drive cycle E:
1Ensure fuel tank is at least a quarter full.
2Carry out Drive Cycle A.
3Switch off ignition.
4Leave vehicle undisturbed for 20 minutes.
5Switch on ignition.
6Connect TestBook and check for fault codes.

FUEL DELIVERY SYSTEM - V8
19-2-8 DESCRIPTION AND OPERATION
Fuel pressure regulator
The fuel pressure regulator is located in the underside of the top cover. The regulator is sealed with two 'O' rings and
retained with a clip.
The regulator is connected to the fuel feed pipe at the top of the pump housing and maintains the fuel pump delivery
pressure to 3.5 bar (50 lbf.in
2). When the fuel delivery pressure exceeds 3.5 bar (50 lbf.in2), the regulator opens and
relieves excess pressure back to the swirl pot via a return pipe. The regulator ensures that the fuel rails and injectors
are supplied with a constant pressure.
The fuel pump delivery pressure and pressure regulator operating pressure can be checked using a Schraeder type
valve located at the rear of the engine on the fuel rail. The valve allows the pump delivery pressure to be measured
using a suitable gauge and an adaptor and hose which are special tools.
Fuel gauge sender
The fuel gauge sender unit comprises a rotary potentiometer operated by a float. The float rises and falls with the fuel
level in the tank and moves the potentiometer accordingly.
Battery voltage is supplied to the potentiometer. The output voltage from the potentiometer varies according to the
resistance through the potentiometer in relation to the fuel level. The output voltage is connected to the fuel gauge in
the instrument pack. The fuel gauge receives a battery voltage input and this is compared with the output voltage from
the potentiometer. The difference between the two voltages determines the deflection of the fuel gauge pointer.
Fuel gauge reading Tank volume litres (US Gallons) * Sender unit resistance
ohms Ω
FULL 95 (25) 15
3/4 71 (18.8) 36
1/2 48 (12.7) 64
1/4 24 (6.4) 110
RESERVE (fuel light ON) 11 (2.9) 158
EMPTY 0 (0) 245
*Tank volumes are approximate.

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 86-3-29
Courtesy headlamps
This feature activates the headlamps for 30 seconds when the lock button on the remote transmitter is held down for
longer than 1 second. The headlamps will extinguish if the BCU receives either a lock or an unlock signal from the
remote transmitter.
The BCU checks the status of the following inputs to determine the correct qualifying conditions for requesting
courtesy headlamps:
lIgnition state.
lRemote locking request.
lRemote unlocking request.
lLazy locking request.
If the ignition is off and a lazy locking request is received, the courtesy headlamps are switched on and an internal
timer is turned on in the BCU which operates for 30 seconds. If the 30 second timer expires or a request for remote
locking or remote unlocking is received, the courtesy headlamps will be turned off.
When main beam is selected, the IDM also provides a signal to the instrument pack to switch on the main beam
warning lamp. An additional signal 'main beam indicator disable' is used to prevent the daylight running lamps
illuminating the main beam indicator when the main beam is in the daylight running lamp state and the main beam
indicator disable signal is on.
Lights on alarm
The lights on alarm in the instrument pack operates when the driver's door is open and the side lamps or headlamps
are on. The system uses inputs from the driver's door switch and the lighting switch to determine the logical conditions
that need to occur for switching on the alarm. The BCU carries out the logic operation and communicates with the
instrument pack using the serial data bus; the instrument pack will be requested to sound the alarm if the logic inputs
indicate that the driver's door is open with the lights still on.
Supply voltage is provided through the lighting switch to the IDM which acts as the signal line to indicate that the lights
are on for the logic circuits in the IDM and BCU. When the driver's door is opened, a second feed is supplied to the
BCU through the driver's door switch to indicate the condition. In this logic condition (lights on and driver's door open)
the BCU signals the instrument pack to operate the audible warning. If the lights are switched off or the driver's door
is closed the logic condition will be changed and the audible warning will be switched off.
Daylight running lamps
The BCU operates the daylight running lamps (where fitted) via the IDM. The daylight running lamps option can be
programmed in one of three states dependent on market/ customer requirements, these are:
lOption 1– no daylight running lamps.
lOption 2 – on with main beam off.
lOption 3 – on with main and dipped beam off and gearbox not in Park.
The BCU will ensure the logical conditions are satisfied for the lamps to operate under the set conditions. The BCU
checks the status of the following inputs to determine the logic action for providing an output to the daylight running
lamp relay:
lMain beam state.
lEngine running (link from instrument pack).
lDipped beam.
lGearbox state.
A voltage supply is fed to the coil of the daylight running lamp relay and the IDM. When the preconditions are satisfied
for daylight running lamp operation, the BCU sends a signal for the IDM to complete the circuit to earth to switch on
the daylight running lamps. The logical inputs are checked to ensure that the engine is running before switching the
relay to turn on the daylight running lamps. The engine running signal has to be present for at least 2 seconds before
the daylight running lamp relay can be switched on.

NAVIGATION SYSTEM
DESCRIPTION AND OPERATION 87-7
Sensor Check
1Call up the SENSORS screen on the LCD:
lIf the navigation CD-ROM has not been installed before, press and hold multifunction button 1 then press
multifunction button 10.
lIf the navigation CD-ROM has been installed before, use the garage menu as detailed above.
2Drive the vehicle forwards a short distance at a speed greater than 2.5 mph (4 km/h) and ensure the road speed
counter on the SENSORS screen starts to increment.
3Select reverse gear and ensure the direction arrows on the SENSORS screen point rearwards.
4Ensure the GPS data on the SENSORS screen is displayed and updated.
NOTE: The GPS data will randomly display a GPS MODULE FAILURE message. This is not a fault condition, and
no action need be taken, provided the GPS data switches between the GPS MODULE FAILURE message and
actual GPS data.
5Exit the SENSORS screen:
lIf the navigation CD-ROM has not been installed before, press and hold multifunction button 1 then press
multifunction button 10.
lIf the navigation CD-ROM has been installed before, press the Nav button.
Calibration Routine
1Park the vehicle outside in an area clear of high buildings, trees etc.
NOTE: The more open the surrounding area is, the faster the system will acquire sufficient GPS satellite signals to
begin calibration. To minimise the calibration time, the vehicle should not be moved again until the calibration
ride.
2Turn the ignition switch to position II. If the navigation computer does not come on, press the navigation
computer ON button.
3If necessary, use the navigation computer multifunction buttons to enter the security code.
4Turn the ignition switch to position 0 and remove the ignition key.
5Press the navigation computer ON button.
6Call up the SENSORS screen on the LCD:
lIf the navigation CD-ROM has not been installed before, press and hold multifunction button 1 then press
multifunction button 10.
lIf the navigation CD-ROM has been installed before, use the garage menu as detailed above.
7Turn the LH rotary control to minimum volume.
8Wait for 30 minutes. If necessary, the vehicle can be left unattended and locked.
NOTE: Land Rover recommend a minimum of 30 minutes be allowed to elapse in order to ensure that only a short
distance need be driven to achieve calibration.
9After the 30 minutes have elapsed, ensure the navigation computer LCD shows a GPS almanac figure of 27 or
higher.
10Start the vehicle engine and allow to idle.
11Install the navigation CD-ROM.
12Wait until the navigation computer LCD prompts for a language to be selected. Turn the RH rotary control to
scroll through the options, highlight the required language and press the RH rotary control to select.
13The navigation computer LCD will prompt for a voice to be selected. Turn the RH rotary control to scroll through
the options, highlight the required voice and press the RH rotary control to select.
14Wait until the navigation computer LCD advises "language has been loaded OK". Press the RH rotary control to
confirm the language and voice selections.
15The navigation computer LCD will default to the CALIBRATION RIDE screen and should show the
CALIBRATION RIDE CAN START message. The GPS data and the road speed counter will also be shown.
16Drive the vehicle over a road route approximating that shown below (it is not necessary to copy the route
exactly). Calibration is complete when the navigation computer LCD switches to show DESTINATION & POI
and the satellite graphic. If all the pre calibration ride conditions were complied with, calibration is typically
achieved within 3 miles (5 km) and usually occurs when the vehicle returns to the start point. However,
calibration may be achieved earlier in the journey and, if it is, there is no need to complete the remainder of the
calibration route.