bonnet LAND ROVER DISCOVERY 1999 User Guide

MAINTENANCE
10-2 PROCEDURES
Diesel underbonnet view
1Coolant header tank
2Brake/clutch fluid reservoir filler caps
3Engine oil dipstick
4Engine oil filler cap
5ACE/PAS fluid reservoirs6Battery
7Auxiliary drive belt
8Air cleaner
9Windscreen washer reservoir

MAINTENANCE
10-8 PROCEDURES
Road wheels
Refit
1.Apply anti-seize compound to wheel hub
centre.
2.Refit road wheels to original hub position.
Tighten wheel nuts to 140 Nm (103 lbf.ft).
Radiator/Intercooler
Check
1.Visually check radiator/intercooler for external
obstructions, remove debris.
2.Visually check fan blades for damage.
Ambient air Temperature and pressure
sensor
Check
1.Check ambient air temperature and pressure
sensor for damage.
Doors, bonnet and fuel filler flap
Check
1.Check operation of each door, door lock,
bonnet catch and fuel filler flap. Ensure doors
close securely.
Lubricate
1.Lubricate door locks, hinges, check straps,
bonnet catch and fuel filler flap.

+ CAPACITIES, FLUIDS,
LUBRICANTS AND SEALANTS,
Lubrication.

EMISSION CONTROL - V8
17-2-14 DESCRIPTION AND OPERATION
The heated oxygen sensor is screwed into threaded mountings welded into the top of the front exhaust pipes at
suitable locations. They are used to detect the level of residual oxygen in the exhaust gas to provide an instantaneous
indication of whether combustion is complete. By positioning sensors in the stream of exhaust gases from each
separate bank of the exhaust manifold, the engine management system is better able to control the fuelling
requirements on each bank independently of the other, so allowing much closer control of the air:fuel ratio and
optimising catalytic converter efficiency.
Two pre-catalytic converter heated oxygen sensors are mounted in the front pipes for monitoring the oxygen content
of the exhaust gas. NAS models also have two additional post-catalytic converter heated oxygen sensors in the
exhaust front pipe.
CAUTION: HO2 sensors are easily damaged by dropping, over torquing, excessive heat or contamination.
Care must be taken not to damage the sensor housing or tip.
The oxygen sensors consist of a ceramic body (Galvanic cell) which is a practically pure oxygen-ion conductor made
from a mixed oxide of zirconium and yttrium. The ceramic is then coated with gas-permeable platinum, which when
heated to a sufficiently high temperature (≥ 350° C) generates a voltage which is proportional to the oxygen content
in the exhaust gas stream.
The heated oxygen sensor is protected by an outer tube with a restricted flow opening to prevent the sensor's
ceramics from being cooled by low temperature exhaust gases at start up. The post-catalytic sensors have improved
signal quality, but a slower response rate.
The pre-catalytic and post-catalytic converter sensors are not interchangeable, and although it is possible to mount
them in transposed positions, their harness connections are of different gender and colour. It is important not to
confuse the sensor signal pins; the signal pins are gold plated, whilst the heater supply pins are tinned,
mixing them up will cause contamination and adversely affect system performance.
Each of the heated oxygen sensors have a four pin connector with the following wiring details:
lSensor signal ground (grey wire – connects to engine management ECM)
lSensor signal (black wire – connects to engine management ECM)
lHeater drive (white wire – connects to engine management ECM)
lHeater supply (white wire – connects to fuse 2, underbonnet fuse box)
The ECM connector pins for exhaust emission control are listed in the following table:
ECM Connector 2 (C635) pin-out details for exhaust emission control system
The heated oxygen sensors should be treated with extreme care, since the ceramic material within them can be easily
cracked if dropped, banged or over-torqued; the sensors should be torqued to the recommended values indicated in
the repair procedures. Apply anti-seize compound to the sensor's threads when refitting.
WARNING: Some types of anti-seize compound used in service are a health hazard. Avoid skin contact.
WARNING: To prevent personal injury from a hot exhaust system, do not attempt to disconnect any
components until the exhaust system has cooled down.
CAUTION: Do not allow anti-seize compound to come into contact with tip of sensor or enter exhaust system.
NOTE: A new HO2 sensor is supplied pre-treated with anti-seize compound.
Pin Number Function Signal Type Control
2-01 Post-cat sensor heater (RH) - NAS only Output, Drive PWM, 12 - 0V
2-07 Post-cat sensor heater (LH) - NAS only Output, Drive PWM, 12 - 0V
2-08 Post-cat sensor (RH) - NAS only Ground, Signal 0V
2-09 Pre-cat sensor (LH) Ground, Signal 0V
2-10 Pre-cat sensor (RH) Ground, Signal 0V
2-11 Post-cat sensor (LH) - NAS only Ground, Signal 0V
2-13 Pre-cat sensor heater (RH) Output, Drive PWM, 12 - 0V
2-14 Post-cat sensor (RH) - NAS only Input, Signal Analogue, 0 - 1V
2-15 Pre-cat sensor (LH) Input, Signal Analogue, 0 - 1V
2-16 Pre-cat sensor (RH) Input, Signal Analogue, 0 - 1V
2-17 Post-cat sensor (LH) - NAS only Input, Signal Analogue, 0 - 1V
2-19 Pre-cat sensor heater (LH) Output, Drive PWM, 12 - 0V

MANIFOLDS AND EXHAUST SYSTEMS - V8
REPAIRS 30-2-15
Gasket - inlet manifold - upper - Without
Secondary Air Injection
$% 30.15.24
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Remove bonnet.

+ EXTERIOR FITTINGS, REPAIRS,
Bonnet.
4.Release MAF sensor harness from clip.
5.Loosen clips securing air intake hose. Release
and remove air intake hose.
Note: Pre 03 MY air intake hose illustrated.
6.Disconnect throttle and cruise control cables.
Release cables from abutment bracket and
position aside. 7.Disconnect EVAP pipe from inlet plenum.
8.Disconnect multiplug from throttle body.
9.Remove clip securing breather hose to throttle
body and release breather hose.
10.Position a drain tray beneath the engine to
collect coolant.
11.Release clips securing coolant hoses to
throttle body and disconnect hoses.

MANIFOLDS AND EXHAUST SYSTEMS - V8
REPAIRS 30-2-17
20.Remove 6 bolts securing upper inlet manifold
and remove upper inlet manifold.
21.Collect upper inlet manifold gasket. Refit
1.Clean upper and lower inlet manifold mating
faces, dowels and dowel holes.
2.Using a new gasket, position upper inlet
manifold. Fit bolts and, working in a diagonal
sequence, tighten to 22 Nm (16 lbf.ft).
3.Connect hose and multiplug to TP sensor.
4.Connect hose and multiplug to IACV. Secure
hose with clip.
5.Secure ht leads to upper inlet manifold.
6.Position ignition coils, fit bolts and tighten to 8
Nm (6 lbf.ft).
7.Ensure clip under ignition coils is located on
fuel pipe.
8.Secure engine harness in bulkhead clips.
9.Fit coolant rail bolt and tighten to 22 Nm (16
lbf.ft).
10.Connect breather hose to inlet plenum.
11.Connect brake servo vacuum pipe to inlet
plenum.
12.Connect EVAP pipe to inlet plenum.
13.Position coolant hoses to throttle body and
secure hose clips.
14.Fit breather hose to throttle body and secure
clip.
15.Connect multiplug to throttle body.
16.Connect throttle and cruise control cables and
secure in throttle body cams.
17.Adjust throttle and cruise control cables.
l

+ ENGINE MANAGEMENT SYSTEM
- V8, ADJUSTMENTS, Cable - cruise
control.
l

+ ENGINE MANAGEMENT SYSTEM
- V8, ADJUSTMENTS, Cable - throttle.
18.Connect air intake hose and tighten clips.
Secure harness to air intake hose.
19.Top-up cooling system

+ MAINTENANCE, PROCEDURES,
Cooling system..
20.Fit bonnet.

+ EXTERIOR FITTINGS, REPAIRS,
Bonnet.
21.Connect battery earth lead.
22.Fit battery cover and secure with fixings.

MANIFOLDS AND EXHAUST SYSTEMS - V8
30-2-18 REPAIRS
Gasket - inlet manifold - upper - With
Secondary Air Injection
$% 30.15.24
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Remove bonnet.

+ EXTERIOR FITTINGS, REPAIRS,
Bonnet.
4.Disconnect multiplug from MAF sensor.
5.Release clip on intake hose and release
harness.
Note: Pre 03 MY air intake hose illustrated.
6.Release and disconnect IACV hose.
7.Loosen clip securing air intake hose to throttle
body.
8.Release 2 clips securing MAF sensor.
9.Release and remove air intake hose.10.Disconnect vacuum hose from air valve.
11.Loosen clip securing air valve hose to air valve.
12.Remove 2 nuts securing air manifold support
bracket to upper inlet manifold.
13.Disconnect 2 air manifold unions from adapters
in cylinder head.
CAUTION: Take care that air manifold pipes
are not damaged during removal of union
nuts.
14.Remove LH air manifold.
15.Disconnect purge valve hose from inlet
manifold.
16.Release purge valve from clips and air control
valve from bracket and lay aside.
17.Disconnect multiplug from IACV.
18.Release clip and disconnect breather hose
from throttle housing.
19.Disconnect multiplug from TP sensor.

MANIFOLDS AND EXHAUST SYSTEMS - V8
REPAIRS 30-2-19
20.Position container to collect spillage.
21.Release clips and disconnect 2 coolant hoses
from throttle housing.
22.Loosen outer cable locknuts and release
throttle and cruise control cables from
abutment.
23.Release throttle and cruise control cables from
clips and throttle cams and position aside.
24.Depress plastic collar and disconnect brake
servo hose from inlet manifold.
25.Release clip and disconnect breather hose
from manifold.
26.Disconnect vacuum hose from manifold.
27.Release engine harness from bulkhead clips
and position aside.
28.Release and remove bonnet seal from rear of
engine bay.
29.Remove 2 bolts securing air pipe and coil
bracket to manifold.
30.Loosen 2 lower bolts securing coil bracket
sufficiently to allow bracket to clear manifold.31.Release plug leads from upper manifold clips.
32.Loosen clip and disconnect air hose from air
valve.
33.Remove 2 nuts securing RH air manifold
support bracket to upper inlet manifold.

MANIFOLDS AND EXHAUST SYSTEMS - V8
30-2-20 REPAIRS
34.Release clip and disconnect IACV hose.
35.Remove 6 bolts securing upper manifold and
remove manifold.
36.Collect upper manifold gasket.
Refit
1.Clean upper and lower inlet manifold mating
faces, dowels and dowel holes.
2.Using a new gasket, position upper inlet
manifold. Fit bolts and, working in a diagonal
sequence, tighten to 22 Nm (16 lbf.ft).
3.Connect IACV hose and secure clip.
4.Connect hose to air valve and tighten clip.
5.Secure plug leads to clips.
6.Fit and tighten nuts securing RH air manifold
support bracket.
7.Align air pipe and coil bracket, fit bolts and
tighten to 8 Nm (6 lbf.ft).
8.Tighten 2 lower bolts securing coil bracket to 8
Nm (6 lbf.ft).
9.Fit bonnet seal.
10.Secure engine harness in bulkhead clips.
11.Connect breather hose to manifold and secure
clip.
12.Connect vacuum hose to inlet manifold.
13.Connect brake servo hose to inlet manifold.
14.Connect throttle and cruise control cables.
15.Adjust throttle cable.

+ ENGINE MANAGEMENT SYSTEM -
V8, ADJUSTMENTS, Cable - throttle.16.Adjust cruise control cable.

+ ENGINE MANAGEMENT SYSTEM -
V8, ADJUSTMENTS, Cable - cruise control.
17.Connect coolant hoses to throttle housing and
secure clips.
18.Connect multiplug to TP sensor.
19.Connect breather hose to throttle housing and
secure with clip.
20.Connect multiplug to IACV.
21.Secure purge valve and air control valve to clips
and bracket.
22.Connect purge hose to manifold.
23.Clean air manifold unions.
24.Apply a small amount of engine oil to top of air
manifold union nuts and around air manifold
pipes.
25.Position air manifold and finger tighten both air
manifold union nuts.
CAUTION: Finger tighten union nuts as far
as possible, damage to air manifold pipes or
adaptors may result if this is not done.
26.Tighten both air manifold union nuts to 25 Nm
(18 lbf.ft).
CAUTION: Ensure that air manifold pipes
are not distorted during tightening
operation.
27.Fit nuts securing air manifold support bracket
and tighten to 25 Nm (18 lbf.ft).
28.Connect hose to air valve and tighten clip.
29.Connect vacuum hose to air valve.
30.Fit air intake hose.
31.Connect multiplug to MAF sensor.
32.Secure harness to clip.
33.Connect battery earth lead.
34.Fit battery cover and secure with fixings.
35.Top up cooling system.

+ MAINTENANCE, PROCEDURES,
Cooling system.
36.Fit bonnet.

+ EXTERIOR FITTINGS, REPAIRS,
Bonnet.

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
ADJUSTMENTS 57-23
9.Release clips and remove air intake hose from
air cleaner housing.
Note: Pre 03 MY air intake hose illustrated.
10.Discard intake 'O' ring and move intake aside
for access.
11.Loosen union securing high pressure pipe to
PAS pump and release pipe.12.Fit adaptor LRT-57-034A to high pressure port
of PAS pump.
13.Fit adaptor LRT-57-035 to existing high
pressure hose.
14.Fit hose LRT-57-002/3 to each adaptor.
15.Fit pressure gauge LRT-57-005 to test valve
LRT-57-001
16.Connect hoses LRT-57-002/3 to LRT-57-001
and tighten unions.
17.Hang pressure gauge in a safe position under
bonnet.
18.Remove PAS reservoir filler cap, fill to level
indicator and refit cap.
19.Connect battery earth lead.
20.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 and test equipment are
free from leaks.
22.Maintain maximum fluid level during test.
23.Open the test valve on LRT-57-001 and start
the engine.
24.With the engine at idle, slowly turn the steering
wheel and hold on full lock.
25.Note the pressure reading on LRT-57-005.
26.Repeat the pressure check for the opposite full
lock.
27.Test pressure should be between 21 and 62
bar, (300 to 900) psi. Dependant on road
surface.
28.With the engine at idle, centralise the steering
wheel. Pressure should read 7 bar (100 psi) or
below.
29.Pressures outside the above tolerance
indicates a fault.
30.To determine if fault is in steering pump or
steering box, close the valve on LRT-57-001 for
a maximum of 5 seconds. Pump damage may
occur if test valve is closed for longer periods.
31.If gauge does not register between 75 and 103
bar, (1500 psi), (maximum pump pressure), the
pump is faulty.
32.If maximum pump pressure is correct suspect
the steering box.