sensor LAND ROVER DISCOVERY 2002 Workshop Manual

FRONT AXLE
54-10 REPAIRS
9.Remove oil seal from axle casing.
Refit
1.Clean drive shaft oil seal recess, oil seal
running surface, wheel hub and swivel hub
mating faces.
2.Lubricate oil seal lip and running surface with
clean differential oil.

+ CAPACITIES, FLUIDS AND
LUBRICANTS, Lubrication.
3.Using tool LRT-54-012 and tool LRT-99-003,
fit new drive shaft oil seal to axle casing. 4.Apply anti-seize compound to wheel hub and
steering knuckle mating faces.
5.Ensure ABS harness is located in cut out in
steering knuckle.
6.Fit drive shaft and wheel hub to axle casing and
align wheel hub with steering knuckle. Fit wheel
hub bolts and tighten to 100 Nm (74 lbf.ft).
7.Connect ABS sensor multiplug and secure
harness to harness bracket and brake hose.
8.Fit front brake disc.

+ BRAKES, REPAIRS, Brake disc -
front.
9.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
10.Remove stand(s) and lower vehicle.
11.Check differential oil level.

+ MAINTENANCE, PROCEDURES,
Front and rear axle.

STEERING
ADJUSTMENTS 57-19
5.Adjust drag link so that taper joint is centralised
in drop arm, then tighten drag link clamp bolts:
Tighten M8 bolts to 22 Nm (16 lbf.ft) and M10
bolts to 33 Nm (24 lbf.ft).
6.Connect drag link to drop arm and tighten nut to
80 Nm (59 lbf.ft).
7.Remove steering box centralising bolt.
8.Remove stand(s) and lower vehicle.
9.Road test the vehicle and check that the
steering wheel is centralised. If steering wheel
is not centralised, proceed as follows.
10.Slacken drag link adjuster clamp bolts.
11.Without disconnecting drag link from drop arm,
adjust the length of the drag link to bring the
steering wheel to the central position.
CAUTION: Repositioning the steering wheel
on its splines cannot correct small (less
than 5
°) errors in steering wheel alignment.
Always rectify small errors in alignment by
adjusting the drag link as detailed above,
ensuring that steering box centralisation is
maintained.
12.Tighten drag link clamp bolts: Tighten M8 bolts
to 22 Nm (16 lbf.ft) and M10 bolts to 33 Nm (24
lbf.ft)
Wheel alignment - front
$% 57.65.01
The following is the only wheel alignment equipment
which has been approved.
lBeissbarth ML 4600 wheel alignment computer
(6 sensor).
lBeissbarth ML 4600-8 wheel alignment
computer (8 sensor).
lBeissbarth ML 4000 wheel alignment computer
(8 sensor wireless).
lHunter S411-14.
Check
1.Ensure tyre pressures are correct and vehicle
is at kerbside weight.
2.Roll vehicle backwards and forwards to relieve
stresses in steering and suspension.
3.Ensure road wheels are positioned straight
ahead.
4.Ensure that wheel alignment equipment is
properly calibrated.
5.Following the equipment manufacturer's
instructions, measure the front wheel
alignment. Compare with the figures given in
General Data.

+ GENERAL DATA, Steering.
Adjust
1.Loosen track rod and adjuster clamp bolts.
2.Rotate adjuster to obtain correct alignment.

+ GENERAL DATA, Steering.
3.Tighten track rod and adjuster clamp bolts:
Tighten M8 bolts to 22 Nm (16 lbf.ft) and M10
bolts to 33 Nm (24 lbf.ft).
4.Recheck front wheel alignment.

STEERING
57-20 ADJUSTMENTS
Power steering pressure check - diesel
models
$% 57.90.10.01
Check
1.Fit gauge and hose LRT- 57-005 to valve
assembly LRT- 57-001 and tighten union.
2.Fit 2 hoses LRT-57-002 to valve assembly
LRT- 57-001 and tighten unions
3.Fit adaptor and hose set LRT-57-041 to LRT-
57-002.
4.Disconnect battery earth lead.
5.Remove engine acoustic cover.
6. LHD only: Remove underbelly panel.

+ EXTERIOR FITTINGS, REPAIRS,
Panel - underbelly.7. LHD only: Disconnect MAF sensor multiplug,
release clips from air cleaner and move intake
hose aside. Discard seal.
8.Position container to collect PAS fluid spillage,
and syphon fluid from PAS reservoir.
9. LHD only: Release PAS reservoir from
mounting move aside, for access to
turbocharger intercooler pipe.
10.Remove vacuum hose from turbocharger
intercooler pipe.
11. LHD only: Release clips and disconnect
turbocharger intercooler pipe from
turbocharger and intercooler.
12.Clean steering box pipe housing.
M57 0902
M57 0903
M57 0904

STEERING
ADJUSTMENTS 57-21
13.Remove bolt from steering box pipe retaining
clip. Leaving the PAS reservoir oil pipe in place,
release pipe retaining clip and PAS cooler pipe
from steering box, discard the seal.
14.Fit tool LRT-57-041 to steering box housing.
15.Fit seal to PAS oil cooler pipe.
16.Fit PAS cooler pipe to LRT-57-041 align the
retaining clip to pipes and tighten bolt to 24 Nm
(18 lbf.ft).
17.Connect test hoses LRT-57-002 to LRT-57-
041 and tighten unions. Ensure all pipes and
fittings are clear of engine rotating parts.18.Hang pressure gauge in a safe position under
bonnet.
19. LHD only: Fit turbocharger intercooler feed
pipe and vacuum connection and fit PAS
reservoir to mounting bracket. Fit air intake
hose to turbocharger and air cleaner and
connect multiplug to MAF sensor. The above
parts must be refitted in order to run the
engine.
20.Fill PAS reservoir, connect battery earth lead.
Start engine and allow air to bleed from PAS
system, by turning steering from lock to lock.
Stop engine and check PAS fluid level.
21.Ensure steering system is free from leaks and
maintain maximum fluid level during test.
22.Open the test valve on LRT-57-001 and start
the engine.
23.With the engine at idle and normal running
temperature, slowly turn the steering wheel and
hold on lock.
24.Note reading on pressure gauge.
25.Repeat pressure check on opposite lock, again
noting the reading on the pressure gauge.
26.The test pressure should be between 21 and 62
bar, (300 to 900 lbf/in
2. Pressure will rise to 62
bar (900 lbf/in2) when held on full lock.
27.With the engine at idle, centralise the steering
wheel. Pressure should read 7 bar (100 lbf/in
2)
or below.
28.Pressure outside the above tolerance indicates
a fault.
29.To determine if fault is in steering pump or
steering rack, close the valve on LRT-57-001
for a maximum of five seconds. Pump damage
may occur if test valve is closed for longer
periods.
30.If the gauge does not register between 75 and
103 bar, (1500 lbf/in
2) (maximum pump
pressure), the pump is faulty.
31.If maximum pump pressure is obtained,
suspect the steering box.
32.On completion, stop engine, disconnect battery
earth lead and syphon fluid from PAS reservoir.
33. LHD only: Disconnect multiplug from MAF
sensor, remove air intake hose clips and move
hose aside.
34. LHD only: Release PAS reservoir from
mounting, for access to turbocharger
intercooler pipe.Remove vacuum hose from
turbocharger intercooler pipe.Release clips and
disconnect intercooler pipe from turbocharger.
35.Remove test equipment from tool LRT-57-041.
36.Remove bolt and clip from steering box.
37.Release PAS cooler pipe from tool LRT-57-041
and discard seal. leaving PAS reservoir oil pipe
in place, release tool LRT-57-041 from
steering box and discard seal.

STEERING
57-22 ADJUSTMENTS
38.Fit new seal, connect PAS cooler pipe and
tighten union nut to 24 Nm (18 lbf ft).
39. LHD only: Fit turbocharger intercooler feed
pipe and vacuum connection. Fit new seal to air
cleaner. Connect air intake hose and secure
clips. Connect multiplug to MAF sensor.
40.Clean chassis and surrounding area.
41.Fit underbelly panel.

+ EXTERIOR FITTINGS, REPAIRS,
Panel - underbelly.
42.Remove adaptor and hose set from tool LRT-
57-041.
43.Check PAS fluid level.
44.Connect battery earth lead.
Power steering pressure check - V8 LHD
models
$% 57.90.10.01
Check
1.Disconnect battery earth lead.
2.Syphon PAS fluid from reservoir.
3.Raise front of vehicle and support on stands.
4.Turn steering on LH lock.
5.Remove 3 screws securing LH splash shield
and remove shield.
6.Release clip securing PAS pipes.
7.Position absorbent cloth to catch spillage.
8.Position container to collect PAS fluid spillage.

FRONT SUSPENSION
60-4 DESCRIPTION AND OPERATION
Description
General
The front suspension comprises two dampers and coil springs, two radius arms, a Panhard rod and an anti-roll bar.
The front axle provides the location points for the dampers, springs, radius arms and the Panhard rod.
The anti-roll bar assembly is an essential part of the front suspension. On vehicles without Active Cornering
Enhancement (ACE) a conventional 'passive' anti-roll bar is fitted. On vehicles fitted with the ACE system, a thicker
diameter anti-roll bar, known as a torsion bar, is used with an actuator at one end.

+ FRONT SUSPENSION, DESCRIPTION AND OPERATION, Description - ACE.
The hydraulic dampers and coil springs provide springing for each front wheel. The long travel dampers, springs and
radius arms provide maximum axle articulation and wheel travel for off-road driving. The front axle is controlled
longitudinally by two forged steel radius arms and transversely by a Panhard rod.
Radius arms
Each radius arm is manufactured from forged steel. Two bushes are pressed into the forward end of the radius arm.
The forward end of the radius arm is located in a fabricated bracket on the axle and secured through the bushes with
two bolts and nuts. A bush is pressed into the rear of the radius arm which is also located in a fabricated bracket on
each chassis longitudinal and secured through the bush with a bolt and nut.
The radius arms prevent longitudinal movement of the front axle and because of their length allow maximum axle
articulation. The stiffness of the bushes in each radius arm also contributes to the vehicle roll stiffness.
Each radius arm has a notch on its lower edge which provides location for the vehicle jack.
Dampers
Two conventional telescopic dampers are used to control body/axle movement. A turret is located on a bracket welded
to the chassis. The upper spring seat has four studs which pass through holes in the bracket and align with
corresponding holes in the turret. Four nuts are screwed onto the studs and secure the turret and upper spring seat
to the chassis.
A fabricated platform is welded to the axle. The platform has two captive nuts which provide for the attachment of the
damper. A lower spring seat is located on the platform. Each spring seat is handed and has a bracket which secures
the ABS sensor harness and the front brake hose.
Each damper is fitted with a bush at its upper end. The bush locates in the top of the turret and is secured with a cross
bolt. The lower attachment point for the damper is also fitted with a bush. This bush has a spindle through its centre
with a hole at each end. The spindle is seated on the lower spring seat and the axle platform and secured with two
bolts. The coil spring is fitted in a compressed state between the upper and lower spring seats and assists the damper
in controlling the body/axle movement. The upper and lower bushes are replaceable items.
Rubber bump stops are fitted to the chassis above each end of the axle. The bump stops are progressive in their
compression and prevent the axle from contacting the chassis in the event of maximum suspension travel being
reached. The bump stops revert to their original shape once the compression load has been removed from them.
The damper functions by restricting the flow of a hydraulic fluid through internal galleries within the damper body. A
chromium plated rod moves axially within the damper. As the rod moves, its movement is limited by the flow of fluid
through the galleries thus providing damping of undulations in the terrain. The damper rod is sealed at its exit point
from the body to maintain fluid within the unit and prevent the ingress of dirt and moisture. The seal also acts as a
wiper to keep the rod outer diameter clean. A plastic shroud protects the rod and slides over the body as the damper
moves. The coil spring aids the damper to extend after being compressed and also aids the damping process.

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-19
The right hand end of the torsion bar has a machined spigot which provides for the attachment of the forged steel
short and long arms. The spigot for the short arm is splined and mates with splines in the short arm. The short arm is
located in a specific position on the splines and clamped to the spigot with a Torx bolt and locknut. The short arm is
not a serviceable item other than the actuator attachment bush. The smaller spigot diameter locates the long arm.
The long arm is fitted with a slipper bush which is located on the spigot and secured with a large washer and a special
bolt. The slipper bush comprises two inner and two outer bushes which are installed from each side of the long arm.
The outer bushes have three lugs which locate in the long arm to prevent the bush from rotating. The long arm also
provides the attachment point for the actuator piston rod and the anti-roll bar link.
The actuator has a forked end which locates on the bush in the short arm and is secured with a bolt and nut. The
piston rod of the actuator locates through a hole in a cast boss on the long arm which is fitted with a special bush. A
shoulder on the piston rod seats in a hole in the bush and a locknut on the end of the piston rod secures the rod to
the long arm and bush.
The front torsion bar is attached to the front chassis cross member. Two rubber bushes are fitted to the torsion bar
and are located in clamp plates. The clamp plates are located in slots in the cross member and secured with bolts.
The rear torsion bar is attached to the tubular cross member at the rear section of the chassis. Two rubber bushes
are fitted to the torsion bar and are located in clamp plates. The clamp plates are located in fabricated brackets
attached to the tubular cross-member and secured with bolts.
Two anti-roll bar links are mounted on brackets on the front and rear axles. Each anti-roll bar link is fitted with a
spherical bearing at each end. One bearing is attached to the link at a 90
° angle. The threaded shank of the bearing
is located through a hole in a bracket on the axle and secured with a locknut; a washer is installed on the threaded
shank between the bearing and the bracket. The second spherical bearing is attached in-line with the link and locates
in the torsion bar on the left hand side and the long arm on the right hand side. The front anti-roll bar links are longer
than the rear links and are not interchangeable.
Accelerometers
Two accelerometers are used for the ACE system. The upper accelerometer is mounted on a bracket, behind the
headlining adjacent to the rear view mirror and the sunroof ECU. The lower accelerometer is located on a bracket on
the inner sill panel under the RH front floor.
The lower accelerometer is the primary sensor used to measure lateral acceleration of the vehicle for roll control. The
upper accelerometer is used by the ECU for roll correction and fault detection in conjunction with the lower
accelerometer.
Each accelerometer is a solid state capacitive acceleration sensor and operates on a 5 V supply from the ECU. The
upper and lower sensors can measure acceleration in the range of
± 1.10 g and return an output to the ECU of
between 0.5 and 4.5 V.
Failures of an accelerometer are recorded by the ECU and can be retrieved using TestBook. A special tool is required
to remove and replace a sensor in the bracket.

FRONT SUSPENSION
60-20 DESCRIPTION AND OPERATION
ACE Electronic control unit (ECU)
1Body Control Unit (Ref. only)
2Bracket
3ACE Electronic control unit
4Attachment nuts 3 off
The ACE ECU is mounted on a bracket behind the passenger glove box and is identified from the other ECU's by its
single electrical harness connector. The single 36 pin connector is located on the lower face of the ECU and mates
with a connector from the main harness. The connector supplies power, ground, signal and sensor information to/from
the ECU for control of the ACE system.
The ACE ECU receives a battery power supply from fuse 15 in the engine compartment fusebox via the ACE relay,
also located in the engine compartment fusebox. The ECU provides an earth path for the relay coil, energising the
coil and supplying power to the ECU.
An ignition on signal is supplied from the ignition switch via fuse 29 in the passenger compartment fusebox. The
ignition on signal provides an input to the ECU which tells the ECU that ignition has been selected on and initiates a
250 ms start time. The start time is used to prevent functions operating when software routines are being initialised.
The ignition on signal, when removed, tells the ECU that the ignition is off. The ECU will remain powered for thirty
seconds after the ignition is turned off. The thirty second period allows the ECU to store values and fault flags in the
memory. These values are read by the ECU when the next ignition on signal is received.
An engine speed signal is transmitted to the ECU from the Engine Control Module (ECM) as a pulsed digital signal.
The engine speed signal is used by the ACE ECU to detect that the engine is running and hydraulic pressure for ACE
system operation is available.

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
60-30 REPAIRS
Ball joint - upper - steering knuckle
$% 60.15.02
CAUTION: Each ball joint can be replaced up to
three times before the axle yoke bore becomes
oversize. Before commencing work, thoroughly
clean surface of joint and check for yellow paint
marks approx. 12 mm (0.5 in) wide. If 3 marks are
found, the axle case must be renewed.
Remove
1.Remove steering knuckle.

+ FRONT SUSPENSION, REPAIRS,
Steering knuckle.
2.Support the chassis on stands.
3.Support the front axle on stands.
4.Remove 2 nuts securing anti-roll bar lower links
to front axle, use a 16 mm spanner to prevent
link joint from turning.
5.Remove 2 bolts securing each front damper to
axle.
6.Remove 8 bolts securing chassis crossmember
and remove crossmember.
7.Remove bolt securing brake hose and ABS
sensor harness bracket to axle.
8.Lower the front axle, release front spring from
damper and remove front spring.9.Fit tool LRT-54-008/22 to tool LRT-54-008.
10.Fit tool LRT-54-008/4 to tool LRT-54-008, and
secure with screw.
11.Fit tool LRT-54-008 with all attachments to
upper ball joint..
12.Fit tool LRT-54-008/5 to the top of the ball
joint.
13.Press upper ball joint from axle. When ram lead
screw reaches the end of its stroke, retract the
lead screw and screw the ram further into the
tool. Repeat the operation until the ball joint is
released from the axle.
14.Dismantle the tools.
Refit
1.Clean upper ball joint location and surrounding
area of axle yoke.
2.Apply a 12 mm (0.5 in) wide yellow paint stripe
on axle yoke, adjacent to upper ball joint
location.