2002 LAND ROVER DISCOVERY check engine

STEERING
REPAIRS 57-29
12. RH drive models with ACE: Position ACE
control arms to access steering box bolts.
13.With assistance remove 4 securing bolts and
remove steering box.
14.Remove centralising bolt from steering box. Refit
1.Fit centralising bolt to steering box.
2. With assistance, position steering box, fit bolts
and tighten to 90 Nm (66 lbf.ft).
3. RH drive models with ACE: Ensure washer is
in place on lower ball joint of anti-roll bar link,
then connect lower ball joint to axle. Tighten nut
to 100 Nm (74 lbf.ft).
4.Position drag link, fit nut and tighten to 80 Nm
(59 lbf.ft).
5.Position Panhard rod, fit bolt and nut and
tighten to 230 Nm (170 lbf.ft).
6.Clean PAS pipe ends and 'O' ring recess.
7.Lubricate new 'O' rings for PAS pipes with clean
PAS fluid.
8.Fit 'O' rings to PAS pipes and position pipes in
steering box. Fit PAS pipe bracket and tighten
bolt to 22 Nm (16 lbf.ft).
9. RHD models: Fit oil filter and housing:
lClean oil filter housing and engine mating
faces.
lLubricate new 'O' ring with clean engine oil
and fit to housing.
lPosition oil filter housing and tighten bolts to
9 Nm (7 lbf.ft).
10.Ensure steering wheel is centralised. Fit
universal joint between steering box and
intermediate shaft and tighten bolts to 25 Nm
(18 lbf.ft).
11.Remove centralising bolt from steering box.
12.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft)..
13.Remove stand(s) and lower vehicle.
14.Check and top up engine oil.
15.Bleed PAS system.

+ STEERING, ADJUSTMENTS,
Hydraulic system - bleed.
16.Centralise steering linkage

+ STEERING, ADJUSTMENTS,
Steering linkage - centralise.

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-13
Lateral acceleration of the body is sensed by two accelerometers and signals are transmitted to the ECU. The engine
driven hydraulic pump supplies a constant hydraulic flow to the valve block. Two directional control valves are
solenoid operated by the ECU and these supply fluid to the applicable side of each actuator to apply an equal and
opposite force to the torsion bar. In operation the ACE system maintains the attitude of the vehicle body when
cornering.
The ACE system uses a semi-synthetic hydraulic fluid which is the same as the fluid used for the PAS system. The
total capacity of the ACE system is 1.62 litres (0.42 US Gallons).
CAUTION: The ACE hydraulic system is extremely sensitive to the ingress of dirt or debris. The smallest
amount could render the system unserviceable. It is imperative that the following precautions are taken.
lACE components are thoroughly cleaned externally before work commences;
lall opened pipe and module ports are capped immediately;
lall fluid is stored in and administered through clean containers.
In the event of an ECU or hydraulic failure the system will fail safe to a 'locked bars' condition. The 'locked bars'
condition will allow the torsion bars to operate in a similar manner as conventional 'passive' anti-roll bars. Prolonged
cornering forces will allow a progressive increase in roll angle due to hydraulic leakage through the actuators and
valve block. Failures will be relayed to the driver by the illumination of the ACE warning lamp in the instrument pack.
Faults are recorded by the ECU and can be retrieved using TestBook.
When the ignition switch is moved to position II, the warning lamp will illuminate for two seconds to check functionality.
The warning lamp functionality can also be checked using TestBook.
TestBook must also be used to perform a bleeding procedure after maintenance operations have been performed to
ensure that complete system bleeding is performed. Trapped air in the system can seriously reduce the system
performance.
Fluid reservoir
The moulded plastic fluid reservoir is mounted on the left hand side of the engine compartment on a bracket which is
attached to the inner wing. The reservoir is dual purpose, being divided into two separate chambers; one for the ACE
system and one for the PAS system. Each chamber has its own filler neck and cap and is identified by moulded
lettering on the reservoir adjacent to each filler.
A non-serviceable filter assembly is fitted in the base of each chamber. The filter is made from fine stainless steel
mesh which is moulded into the body of the reservoir. The filter removes particulate matter from the fluid before it is
drawn into the hydraulic pump.
Upper and lower fluid level marks are moulded onto the reservoir body. The capacity of the ACE reservoir chamber
to the upper level mark is 0.5 litre (0.13 US Gallon).

FRONT SUSPENSION
ADJUSTMENTS 60-27
ADJUST ME NTS
ACE hydraulic system bleeding
$% 60.60.13
Introduction
CAUTION: The ACE hydraulic system is
extremely sensitive to the ingress of dirt or
debris. The smallest amount could render the
system unserviceable. It is imperative that the
following precautions are taken.
lACE components are thoroughly cleaned
externally before work commences;
lall opened pipe and module ports are
capped immediately;
lall fluid is stored in and administered
through clean containers.
Check
1.Check the ACE system fluid level.

+ FRONT SUSPENSION,
ADJUSTMENTS, Fluid level check - ACE
system.
Bleed
1.With vehicle on ramp, connect TestBook and
follow bleed procedure as described.
Fluid level check - ACE system
$% 60.60.14
Introduction
CAUTION: The ACE hydraulic system is
extremely sensitive to the ingress of dirt or
debris. The smallest amount could render the
system unserviceable. It is imperative that the
following precautions are taken.
lACE components are thoroughly cleaned
externally before work commences;
lall opened pipe and module ports are
capped immediately;
lall fluid is stored in and administered
through clean containers.
Check
1.Clean reservoir around fluid level marks.
2.Visually check fluid level through side of
reservoir. Fluid level must be between upper
and lower fluid level marks.
Top-up
1.Clean reservoir around filler cap.
2.Remove filler cap from reservoir and fill to
upper fluid level mark with recommended fluid.

+ CAPACITIES, FLUIDS AND
LUBRICANTS, Fluids.
3.Fit filler cap to reservoir
4.Start and run engine for 2 minutes to circulate
fluid.
5.If necessary, top-up reservoir to upper fluid
level mark.

FRONT SUSPENSION
REPAIRS 60-49
Refit
1.Ensure new filter has 'O' ring fitted, then fit filter
to valve block.
2.Fit new 'O' ring to filter cap. Fit cap and tighten
to 35 Nm (26 lbf.ft).
3.Lower vehicle.
4.Check fluid level in ACE/PAS reservoir.

+ FRONT SUSPENSION,
ADJUSTMENTS, Fluid level check - ACE
system.
5.Start and run engine for 2 minutes, then re-
check fluid level in ACE/PAS reservoir.

+ FRONT SUSPENSION,
ADJUSTMENTS, Fluid level check - ACE
system.
Pressure transducer - ACE
$% 60.60.22
CAUTION: The ACE hydraulic system is
extremely sensitive to the ingress of dirt or
debris. The smallest amount could render the
system unserviceable. It is imperative that the
following precautions are taken.
lACE components are thoroughly cleaned
externally before work commences;
lall opened pipe and module ports are
capped immediately;
lall fluid is stored in and administered
through clean containers.
Remove
1.Raise vehicle on a ramp.
2.Disconnect multiplug from transducer.
3.Position container to collect fluid spillage.
4.Remove pressure transducer and discard 'O'
ring.
CAUTION: Always fit plugs to open
connections to prevent contamination.

REAR SUSPENSION
64-18 DESCRIPTION AND OPERATION
The ECU supplies a 5 V current to each of the height sensors. Each height sensor uses the current to supply an
analogue input to the ECU. The ECU can calculate from the input received from each height sensor the height of the
vehicle and can then power the air supply unit as necessary to raise or lower one or both air springs to level the
vehicle.
When SLS compressor operation is required, the ECU provides a battery supply to energise the SLS relay located in
the engine compartment fusebox. When the relay contacts close, a 12 V supply passes through fusible link 9 in the
engine compartment fusebox, through the relay contacts and operates the air supply unit compressor. The ECU will
then supply power to operate one or both air control valve solenoids and/or the exhaust valve solenoid to inflate or
deflate the air springs as required. The compressor does not need to be powered to deflate the air springs.
The ECU also controls the operation of the SLS audible warning, the SLS warning lamp and the ORM warning lamp.
When the ignition is switched to position II, the ECU performs a three second bulb check and illuminates the SLS and
ORM warning lamps in the instrument pack to check for operation. When the system is operating or a fault is sensed
by the ECU, the ECU will operate the appropriate warning lamp and audible warning as required. The audible warning
is operated by the Body Control Unit (BCU) when it receives a signal from the SLABS ECU. The audible warning is
emitted from a speaker at the rear of the instrument pack.
Depressing the ORM switch for a minimum of 0.5 seconds, completes an earth which the ECU uses as a signal to
initiate the ORM if conditions allow. When the ECU starts ORM, the same earth that was completed by the ORM
switch is pulled to earth by the ECU to activate the ORM warning lamp. The ECU checks for a further operation of the
ORM switch by continuously and very quickly removing the earth for the ORM warning lamp. If the ORM switch is
operated for more than 0.5 seconds, the ECU will detect this and de-activate the ORM.
The SLS part of the SLABS ECU also uses the road speed data generated within the SLABS ECU by the ABS system.
Operation of ORM and extended mode are road speed sensitive and use the ABS signal to monitor the vehicle speed.
When the accessory remote handset is used for the SLS lower and raise functions, the handset transmits RF signals
which are received by the same RF receiver used for the alarm/remote door locking system. The RF receiver passes
this data as a 25 Hz PWM signal to the BCU. The BCU then transmits this data to the SLABS ECU as raise or lower
data. TestBook is required to program the BCU for remote handset operation.
SLABS ECU connector pin details
Connector/Pin No. Description Input/Output
C0504
1 Battery supply Input
2 Ignition supply Input
5 K line (diagnostics) Input/Output
12 EarthInput
C0654
1 Left height sensor supply Output
2 Left height sensor earth Input
3 Left height sensor signal Input
4 Right height sensor supply Output

BRAKES
DESCRIPTION AND OPERATION 70-23
Typical disabled times
Diagnostics
While the ignition is on, the diagnostics function of the SLABS ECU monitors the system for faults. In addition, the
return pump is tested by pulsing it briefly immediately after the engine starts provided vehicle speed exceeded 4.4
mph (7 km/h) during the previous ignition cycle. If a fault exists in a warning lamp circuit, the lamp will not illuminate
during the lamp check at ignition on but, provided there are no other faults, the related function will otherwise be fully
operational. If a fault is detected during the power up, the SLABS ECU stores a related fault code in memory and
illuminates the appropriate fault warning lamps. If a fault is detected later in the drive cycle, the SLABS ECU also
sounds the audible warning three times.
Fault codes and diagnostic routines can be accessed by connecting Testbook to the vehicle's diagnostic connector
in the driver's footwell.
Warning lamp fault operation
After detecting a fault, the SLABS ECU selects an appropriate default strategy which, where possible, retains some
operational capability. A shuttle valve switch fault and throttle position signal fault are classified as permanent faults.
If a permanent fault is detected, the related warning lamp illumination and default strategies are automatically
employed in subsequent ignition cycles, even if the fault is intermittent, until the fault has been rectified and cleared
from memory. If a non permanent fault is detected, the related warning lamp illumination and default strategies will
only be employed in subsequent ignition cycles if the fault is still present.
After rectification of an ABS sensor fault, the ABS and ETC functions are disabled, and the ABS warning lamp remains
illuminated after the lamp check, until vehicle speed exceeds 9.4 mph (15 km/h) (to allow additional checks to be
performed).
Vehicle speed, mph (km/h) Time, minutes
1.3 (2) 40
12.5 (20) 33
15.6 (25) 17
25.0 (40) 9
31.3 (50) 6
Item Check Warning lamp
ABS Brake ETC HDC
fault
ABS sensors Resistance (to check status) On On On On
Brake lamps relay Open/Short circuit Off Off Off On
Engine data Sticking throttle, signal failure, data corruption Off Off On On
Inlet solenoid valves Open/Short circuit On On On On
Outlet solenoid valves Open/Short circuit On On On On
Reference earth Connection to earth On On On On
Return pump monitor Correct pump operation On On On On
Return pump relay Open/Short circuit On On On On
Shuttle valve switches Open/Short circuit On On On On
SLABS ECU Internal failure On On On On
Supply voltages Range (10 to 16 V) On On On On

RESTRAINT SYSTEMS
75-10 DESCRIPTION AND OPERATION
SRS warning lamp
The SRS warning lamp illuminates for 5 seconds during system readiness check on starting the engine. The SRS
warning lamp extinguishes for one second after the system readiness check is performed. If a fault is present the
warning lamp then illuminates continuously. If no fault is present, the SRS warning lamp remains extinguished. If a
system fault occurs in excess of two seconds after the readiness check has been completed, the SRS warning lamp
illuminates for that ignition cycle. It remains illuminated for a minimum of 12 seconds
± 4 seconds for all fault
conditions.
The SRS warning lamp will only illuminate for low voltage concerns while the low voltage condition is present. If the
low voltage condition is corrected, the SRS warning lamp extinguishes and the fault is recorded in the DCU's memory.

EXTERIOR FITTINGS
76-2-10 REPAIRS
10.Remove grommet from engine bulkhead.
11.Tie a draw string to end of bonnet release
cable in passenger compartment.
12.Pull bonnet release cable, from bonnet lock
end, until whole of cable is released.
13.Untie draw string from bonnet release cable
and remove cable.
14.Remove grommet from cable.
Refit
1.Fit grommet to bonnet release cable.
2.Tie draw string to passenger compartment end
of bonnet release cable.
3.Use draw string to pull bonnet release cable
into position.
4.Fit grommet to engine bulkhead.
5.Untie draw string from bonnet release cable.
6.Position bonnet release lever assembly and
connect bonnet release cable to lever.
7.Fit release lever assembly to body and tighten
nuts to 10 Nm (7 lbf.ft) .
8.Connect bonnet release cable to lock.
9.With assistance, operate bonnet release lever
and check for correct operation of lock.
10.Fit fascia closing panel and secure with
fasteners.
11.Fit bonnet lock shield and secure with rivets.
12.Position headlamp to body, connect multiplugs
and fit headlamp to sockets.
13.Fit front grille.

+ EXTERIOR FITTINGS, REPAIRS,
Grille - front - up to 03MY.
Cable - bonnet release - from 03MY
$% 76.16.29
Remove
1.Remove the front grille.

+ EXTERIOR FITTINGS, REPAIRS,
Grille - front - from 03MY.
2.Drill out 4 rivets securing bonnet lock shield to
the bonnet locking platform and remove the
shield.
3.Disconnect bonnet release cable from the
bonnet lock.
4.Disconnect bonnet release cable from the front
panel retaining clip.
M76 4573