1999 LAND ROVER DISCOVERY battery

STEERING
REPAIRS 57-33
21.With assistance remove 2 nuts and bolts
securing RH engine mounting to chassis.
22.Support the engine weight on a jack.
CAUTION: To prevent damage to
components, cushion the jack pad with a
block of wood or hard rubber.
23.Raise the engine sufficiently to allow the
steering box to clear the sump.
24. Models with ACE: Position ACE control arms
to access steering box bolts. 25.With assistance remove 4 bolts securing
steering box and remove steering box.
26.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.Lower the engine onto its mountings. Fit engine
mounting bolts and tighten to 85 Nm (63 lbf.ft).
4. 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).
5.Position drag link, fit nut and tighten to 80 Nm
(59 lbf.ft).
6.Position Panhard rod, fit bolt and nut and
tighten to 230 Nm (170 lbf.ft).
7.Position coolant rail and secure with clips and
bolt.
8.Fit coolant hoses and secure with clips.
9. Models with ACE: Fit and tighten bolt
securing ACE pipes to chassis.
10.Clean PAS pipe ends and 'O' ring recess.
11.Lubricate new 'O' rings for PAS pipes with clean
PAS fluid.
12.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).
13.Ensure steering wheel is centralised. Fit
universal joint between steering box and
intermediate shaft and tighten bolts to 25 Nm
(18 lbf.ft).
14.Remove centralising bolt from steering box.
15.Fit intercooler to turbo hose and secure with
clips.
16.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft).
17.Remove stand(s) and lower vehicle.
18.Connect battery earth lead.
19.Fit battery cover.
20.Refill cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
21.Bleed PAS system.

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

+ STEERING, ADJUSTMENTS,
Steering linkage - centralise.

STEERING
57-34 REPAIRS
Steering box - RHD - diesel
$% 57.10.01
Remove
1.Remove battery cover.
2.Disconnect battery earth lead.
3.Drain cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
4.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.
5.Remove RH front road wheel.
6.Ensure steering wheel is centralised, remove
key from steering lock and engage column lock.
7.Fit centralising bolt to steering box.
8.Remove 3 bolts securing intermediate shaft
and universal joint.
9.Push intermediate shaft upwards, release and
remove universal joint.
CAUTION: Do not turn the steering wheel
with the intermediate shaft or universal joint
disconnected as damage to the rotary
coupler and the steering wheel switches
may occur.
10.Position container below PAS pipes to catch
fluid spillage.

STEERING
REPAIRS 57-37
Refit
1.Fit centralising bolt to steering box.
2.With assistance, position steering box to
chassis, fit bolts and tighten to 90 Nm (66 lbf.ft).
3. Models with ACE: Ensure washer is in place
on lower ball joint of anti-roll bar link, then
connect lower ball joint to axle and 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.Position coolant rail and secure with clips and
bolt.
7.Fit coolant hoses and secure with clips.
8. Models with ACE: Fit and tighten bolt
securing ACE pipes to chassis.
9.Clean PAS pipes ends and 'O' ring recess.
10.Lubricate new 'O' rings for PAS pipes with
clean PAS fluid.
11.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).
12.Ensure steering wheel is centralised. Fit
universal joint between steering box and
intermediate shaft and tighten bolts to 25 Nm
(18 lbf.ft).
13.Remove centralising bolt from steering box.
14.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft).
15.Remove stand(s) and lower vehicle.
16.Connect battery earth lead.
17.Fit battery cover.
18.Refill cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
19.Bleed PAS system.

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

+ STEERING, ADJUSTMENTS,
Steering linkage - centralise.
Seal - input shaft - steering box
$% 57.10.16
Remove
1.Remove steering box:
lFor V8 models:

+ STEERING, REPAIRS, Power
steering box - V8.
lFor LHD diesel models:

+ STEERING, REPAIRS, Power
steering box - LHD - diesel.
lFor RHD diesel models:

+ STEERING, REPAIRS, Steering
box - RHD - diesel.
2.Secure steering box in vice.
3.Remove circlip and extract oil seal from
steering box. Take care not to damage
surface of the shaft.
Refit
1.Clean oil seal recess and input shaft.
2.Lubricate new seal with clean PAS fluid.
3.Fit seal using LRT-57-503.
4.Fit circlip.
5.Fit steering box.
lFor V8 models:

+ STEERING, REPAIRS, Power
steering box - V8.
lFor LHD diesel models:

+ STEERING, REPAIRS, Power
steering box - LHD - diesel.
lFor RHD diesel models:

+ STEERING, REPAIRS, Steering
box - RHD - diesel.

FRONT SUSPENSION
60-8 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
60-18 DESCRIPTION AND OPERATION
ACE Electronic control unit (ECU)
1Body Control Unit (Ref. only)
2Bracket3ACE 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.
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.

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-21
Engine speed signal
Reverse gear signal
Ignition ON signal
Pressure control valve failure
Directional control valves
Failure Effect
Open circuit No ACE control - 'Locked bars' condition
Short circuit - Ground No ACE control - 'Locked bars' condition
Short circuit - VBatt No ACE control - 'Locked bars' condition
Failure Effect
Open circuit No reverse signal to ECU. ACE active in reverse,
may give abnormal handling when reversing
Short circuit - Ground No reverse signal to ECU. ACE active in reverse,
may give abnormal handling when reversing
Short circuit - VBatt Permanent reverse signal to ECU. Permanent
'Locked bars' condition
Failure Effect
Open circuit ECU does not receive ignition ON signal. No ARC
control, 'Locked bars' condition
Short circuit - Ground ECU does not receive ignition ON signal. No ARC
control, 'Locked bars' condition
Short circuit - VBatt Permanent ignition ON signal to ECU. Possibility of
flat battery
Failure Effect
Open circuit No ACE control
Short circuit - Ground No ACE control
Short circuit - VBatt No ACE control
Valve stuck open No ACE control
Valve stuck closed Maximum system pressure - no proportional control.
Pressure relief valve operating at 185 bar (2683
lbf.in
2)
Failure Effect
DCV 1 DCV 2
Valve open or stuck open Valve open or stuck open No ACE control - Anti-roll bars floppy
Valve closed or stuck
closedValve closed stuck
closedNo ACE control - 'Locked bars' condition (default)
Valve open or stuck open Valve closed or stuck
closedVehicle leans to left when pressure is applied to
actuators
Valve closed or stuck
closedValve open or stuck open Vehicle leans to right when pressure is applied to
actuators

REAR SUSPENSION
DESCRIPTION AND OPERATION 64-11
1Battery supply (via SLABS relay)
2Ignition supply
3RH height sensor
4LH height sensor
5Off-road mode warning lamp
6Audible warning speaker
7Instrument pack
8SLS warning lamp
9Fusible link 9
10SLS relay
11Air supply unit
12RH air valve
13LH air valve
14Exhaust valve
15Diagnostic socket
16Off-road mode switch
17SLS remote handset
18Body Control Unit (BCU)
19Door switches
20SLABS ECU
21Engine Control Module (ECM)

REAR SUSPENSION
DESCRIPTION AND OPERATION 64-17
SLABS ECU
1SLABS ECU
2Bracket
3BCU (Ref. only)4ACE ECU (Ref. only)
5Attachment nuts
The SLABS ECU is mounted on a bracket behind the passenger glove box and is identified from the other ECU's by
its five connectors. The five connectors are located on the lower face of the ECU and mate with five connectors from
the main harness. The twelve, six and eighteen pin connectors are used to supply inputs and outputs to and from the
ECU. The remaining connectors are used for the ABS operation.

+ BRAKES, DESCRIPTION AND OPERATION, Description.
The SLABS ECU receives a continuous battery supply from fuse 11 in the engine compartment fusebox. An ignition
'ON' signal is supplied from the ignition switch via fuse 28 in the passenger compartment fusebox. The ECU has the
ability to control when it requires power and is not reliant on the ignition signal for it to power up.
The ECU incorporates a counter which times the operation of the SLS system and prevents the compressor
exceeding its duty cycle. The ECU can remain powered for up to 1.5 hours after ignition off is sensed to allow the
counter to continue running to avoid an ignition cycle resetting the counter.
Opening any of the doors will power up the ECU, irrespective of ignition switch position. The door open signal is
sensed by the door switch completing an earth path which is sensed by the ECU. The ECU cannot differentiate
between any of the doors. The door open signal powers the ECU for up to 30 minutes to allow the vehicle to re-level
when a load is removed or passengers leave the vehicle.
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.