2002 LAND ROVER DISCOVERY warning

STEERING
57-50 REPAIRS
Drag link
$% 57.55.17
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. RHD vehicles: Remove the LH front road
wheel.
3. LHD vehicles: Remove the RH front road
wheel.
4.Remove nut and bolt securing damper to drag
link and release damper.
5.Remove 2 nuts securing drag link to drop arm
and steering knuckle.
6.Using LRT-57-036 break taper joints and
remove drag link.
CAUTION: Before disconnecting any part of
the steering linkage, ensure the road wheels
are positioned straight ahead and the
steering wheel is prevented from turning.
Unrestricted turning of the steering wheel
will damage the SRS rotary coupler.7.Loosen adjuster clamp bolts and remove ball
joint and adjuster.
8.Remove clamps from adjuster and drag link.
Refit
1.Clean adjuster, clamps and ball joint.
2.Fit clamps to drag link and adjuster. Screw in
adjuster and ball joint.
3.Clean ball joint tapers and taper seats.
4.Fit drag link to drop arm and tighten nut to 80
Nm (59 lbf.ft).
5.Adjust length of drag link so that ball joint taper
is centralised in steering knuckle.
6.Fit drag link to steering knuckle and tighten nut
to 80 Nm (59 lbf.ft).
7.Tighten drag link adjuster clamp bolts. Tighten
M8 bolts to 22 Nm (16 lbf.ft) and M10 bolts to
33 Nm (24 lbf.ft)
8.Align damper to drag link, fit nut and bolt and
tighten to 125 Nm (92 lbf.ft).
9.Check steering linkage is centralised.

+ STEERING, ADJUSTMENTS,
Steering linkage - centralise.
10.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
11.Remove stand(s) and lower vehicle.

STEERING
REPAIRS 57-51
Damper - steering
$% 57.55.21
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 2 nuts and bolts securing steering
damper to drag link and chassis.
3.Compress damper and remove from vehicle.
Refit
1.Position damper to chassis and drag link. Fit
nuts and bolts and tighten to 125 Nm (92 lbf.ft).
2.Remove stand(s) and lower vehicle.
Steering wheel
$% 57.60.01.30
Remove
1.Remove drivers airbag.

+ RESTRAINT SYSTEMS, REPAIRS,
Airbag module - drivers.
2.Disconnect horn multiplug.
3.Centralise steering wheel with road wheels in
straight ahead position.
4.Restrain steering wheel and loosen self locking
nut securing steering wheel to column.
5.Release steering wheel from column.
6.Remove and discard self locking nut.
7.Remove steering wheel.
8.Attach tape across edge of rotary coupler to
retain correct setting.

FRONT SUSPENSION
60-10 DESCRIPTION AND OPERATION
ACE system control diagram
1Upper accelerometer
2Lower accelerometer
3Pressure transducer
4Directional control valve
5Directional control valve
6Pressure control valve
7Instrument pack warning lamp
8Diagnostic socket9Reverse lamp switch
10SLABS ECU
11Engine Control Module (ECM)
12Ignition feed
13ACE relay
14Battery supply
15ACE ECU
M60 0589B
12
5
4
3
6
7
8
9
10
11
12
13
14
15

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
DESCRIPTION AND OPERATION 60-21
A road speed signal is transmitted to the ACE ECU as a pulsed digital signal from the Self-levelling/Anti-lock Braking
System (SLABS) ECU. The road speed signal is used by the ACE ECU for on and off-road roll compensation.
When reverse gear is selected, an input is received from the reverse lamp switch. When the ACE ECU detects that
reverse gear has been selected, the ACE system reverts to a 'locked bars' condition until reverse gear is disengaged.
The diagnostic connection allows diagnostic interrogation of the ACE ECU. The diagnostic socket allows diagnostic
equipment to be connected to interrogate the ACE ECU for fault codes.
When system faults are detected by the ECU, the ACE warning lamp in the instrument pack is illuminated by the ECU
continuously in amber for minor faults or flashing red with an audible warning for faults which require the driver to stop
the vehicle immediately.
The ACE ECU supplies a control current to the pressure control valve in the valve block. The current supplied by the
ECU is determined by a number of input signals from the upper and lower accelerometers, road speed etc.. The
pressure control valve controls the hydraulic pressure supplied to the actuators proportional to the current supplied
by the ECU.
Power is supplied to the two solenoid operated directional control valves (DCV's) in the valve block by the ECU.
Together, the DCV's control the direction of flow of hydraulic fluid to the actuators. When the ECU supplies power to
the solenoids the valves open allowing hydraulic fluid to flow to the actuators. When power is removed the valves
close.
The pressure transducer in the valve block receives a 5 V supply from the ECU. The pressure transducer measures
hydraulic pressures in the range of 0 to 180 bar (0 to 2610 lbf.in
2) and returns a linear output voltage to the ECU
dependent on hydraulic pressure.
The ECU supplies a 5 V current to each of the accelerometers. Each accelerometer is capable of measuring lateral
acceleration in the range of
± 1.10 g. An analogue input to the ECU of between 0.5 and 4.5 V relative to the lateral
acceleration sensed is returned by each accelerometer. The ECU processes the two signals received to produce a
'pure' lateral acceleration signal which is then used as the main control signal for the ACE system.
ACE ECU connector pin details
Pin No. Description Input/Output
1 Not used -
2 Not used -
3SpareInput
4 Not used -
5 Road speed Input
6 ARC relay Output
7 to 9 Not used -
10 K line (diagnostics) -
11 Ignition switch Input
12 Accelerometer - lower (supply) Output
13 Pressure transducer (supply) Output

FRONT SUSPENSION
60-22 DESCRIPTION AND OPERATION
Failure modes
Failures where the vehicle can still be driven safely are indicated by the ACE warning lamp illuminating continuously
with an amber colour. The amber warning lamp will remain illuminated until the ignition is turned off. For all faults the
warning lamp will only illuminate again if the fault is still present. Failures which require the driver to stop the vehicle
immediately are indicated by the ACE warning lamp flashing with a red colour and an audible warning. All faults are
recorded by the ACE ECU and can be retrieved with diagnostic equipment.
The following tables show the type of system failures and their effects on the system operation. Torsion bar 'floppy'
means that fluid is allowed to circulate freely through the system. With no pressure in the actuators the torsion bar will
have no effect on vehicle roll. 'Locked bars' means that all pump flow is directed through the valve block and returns
to the reservoir. Both DCV's close and fluid is trapped in the actuators but can flow from one actuator to the other via
the valve block. In this condition the torsion bar will perform similar to a conventional anti-roll bar, resisting roll but still
allowing the axles to articulate.
Acceleration sensors
Pressure transducer
14 Reverse switch Input
15 Accelerometer - lower (signal) Input
16 Pressure transducer (signal) Input
17 Accelerometer - upper (signal) Input
18 Accelerometer - upper (supply) Output
19 Engine speed Input
20 Main earth 1 -
21 Pressure transducer (earth) Input
22 DCV 2 (earth) Input
23 DCV 1 (earth) Input
24 DCV 1 & 2 (supply) Output
25 Pressure control valve (earth) Input
26 Not used -
27 Pressure control valve (supply) Output
28 Main supply (+ V Batt) Input
29 to 31 Not used -
32 Main earth 2 -
33 Accelerometer - lower (signal) Input
34 Accelerometer - upper (signal) Input
35 Not used -
36 Warning lamp Output
Failure Effect
Valve stuck closed No ACE control
Short circuit - Ground No ACE control
Short circuit - VBatt No ACE control
Loose sensor Erractic ACE activity when driving in straight line
Failure Effect
Short circuit - VBatt Large sensor dead band - possible random movementsPin No. Description Input/Output

FRONT SUSPENSION
REPAIRS 60-29
REPAIRS
Bushes - Panhard rod
$% 60.10.07
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 2 nuts and bolts securing Panhard rod
to axle and chassis.
3.Remove Panhard rod from vehicle.
4.Use tool LRT-60-013 fitted with LRT-60-013/1
and LRT-60-013/3 to press out bushes from
Panhard rod. Refit
1.Clean bush locations in Panhard rod.
2.Use tool LRT-60-013 fitted with LRT-60-013/1
and LRT-60–013/2 to press new bushes into
Panhard rod. Ensure pressure is applied to
the outer edge of the bush, not the rubber
inner.
3.Position Panhard rod to axle and chassis.
4.Fit bolts securing Panhard rod but do not
tighten at this stage.
5.Remove stand(s) and lower vehicle.
6.Tighten bolts securing Panhard rod to 230 Nm
(170 lbf.ft).
CAUTION: Nuts and bolts must be tightened
with weight of vehicle on suspension.

FRONT SUSPENSION
60-34 REPAIRS
Road spring - front
$% 60.20.11
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.Support vehicle under chassis.
3.Remove front road wheels.
4.Support weight of front axle.
5.Remove 2 nuts securing anti-roll bar links to
front axle and disconnect links from axle.
6.Remove 2 bolts securing each damper to front
axle.
WARNING: Make sure the axle cannot move
when the damper is disconnected. The
damper limits the downward movement of
the axle. If the axle is not restrained,
disconnecting the damper will allow
unrestricted movement which may cause
personal injury or damage to equipment.
7.Lower front axle.
CAUTION: Ensure brake hoses and ABS
sensor harnesses are not damaged when
lowering front axle.
8.Release and remove front spring from damper.Refit
1.Clean front spring seats.
2.Position front spring, with close coil uppermost,
over damper and locate in cut out in lower
spring seat.
3.Ensure both front springs are correctly located
in spring seats and raise front axle. Fit bolts
securing both dampers to front axle and tighten
to 45 Nm (33 lbf.ft).
4.Ensure washer is in place on lower ball joint of
each anti-roll bar link, then connect lower ball
joints to axle. Tighten nuts to 100 Nm (74 lbf.ft).
5.Fit front road wheels and tighten nuts to 140
Nm (103 lbf.ft).
6.Remove stands and lower vehicle.