low oil pressure LAND ROVER DISCOVERY 2002 Repair Manual

REAR SUSPENSION
64-16 DESCRIPTION AND OPERATION
Air springs
1Top plate
2Voss connector
3Air bag
4Piston
On vehicles without SLS, coil springs are used. On vehicles with SLS two air springs are fitted between the chassis
and the rear axle to replace the coil springs. Each air spring is located at its base on a fabricated platform on the rear
axle. The top of the spring locates in a fabricated bracket attached to the outside of each chassis longitudinal.
The plastic base piston is recessed with a boss with two lugs moulded in the centre for attachment to the axle. The
piston is secured by locating the lugs in a slotted hole in the axle platform and rotating the spring through 90
°, locating
the lugs in the slot. The plastic top plate has two grooved pins which locate through holes in the chassis bracket. Two
spring clips locate on the grooved pins and retain the top of the spring in position.
Each air spring comprises a top plate, an air bag and a base piston. The air bag is attached to the top plate and the
piston with crimped rings.
The air bag is made from a fibre reinforced flexible rubber material which allows the spring to expand with air pressure
and deform under load. The top plate comprises the two bonded grooved pins and a female Voss connector in the
centre. The Voss connector allows for the attachment of the air supply pipe from the air supply unit. The piston is also
made from plastic and is shaped to optimise the springs characteristics.

AIR CONDITIONING
82-4DESCRIPTION AND OPERATION
Refrigerant system
Schematic of air conditioning system
1Evaporator
2Thermostatic expansion valve
3Low pressure servicing connection
4Outlet to rear A/C system (where fitted)
5Dual pressure switch
6Receiver drier
7Cooling fan
8Condenser
9Compressor10Inlet from rear A/C system (where fitted)
11High pressure servicing connection
12Air flows
aAmbient air
bCooled air
cAmbient air through condenser
13Refrigerant
aLiquid
bVapour
The refrigerant system transfers heat from the vehicle interior to the outside atmosphere to provide the heater
assembly with dehumidified cool air. The system comprises a compressor, condenser, receiver drier, thermostatic
expansion valve and evaporator, joined together by refrigerant lines. The system is a sealed, closed loop, filled with
a charge weight of R134a refrigerant as the heat transfer medium. Oil is added to the refrigerant to lubricate the
internal components of the compressor.

AIR CONDITIONING
DESCRIPTION AND OPERATION 82-17
RH temperature. Illuminates to show the RH temperature selection, external air temperature or diagnostic fault code.
Blower speed. Illuminates when the blower speed is manually selected. Also illuminates in the automatic modes when
one of the temperatures is set to LO or HI.
External air temperature. EXT illuminates to show that external air temperature is selected on.
All temperature indications on the display are in either
°C or °F. For 1 second after the system is first switched on, the
display shows only
°C or °F, in the LH temperature window, to indicate which temperature scale is in use. After 1
second, the
°C or °F indication goes off and the display shows all relevant outputs.
Temperature conversion: While the system is on, the temperature indications on the display can be switched between
the two scales by pressing and holding the fresh/recirculated air switch, then pressing and holding the A/C on/off
switch until the audible warning sounds (approximately 3 seconds).
Dual pressure switch
The dual pressure switch protects the refrigerant system from extremes of pressure. The normally closed switch is
installed in the top of the receiver drier. If minimum or maximum pressure limits are exceeded the switch contacts
open, causing the compressor clutch to be disengaged. The minimum pressure limit protects the compressor, by
preventing operation of the system unless there is a minimum refrigerant pressure (and thus refrigerant and
lubricating oil) in the system. The maximum pressure limit keeps the refrigerant system within a safe operating
pressure.
Dual pressure switch nominal operating pressures
Evaporator temperature sensor
The evaporator temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input of the
evaporator air outlet temperature. The evaporator temperature sensor is installed in a clip which locates in the
evaporator matrix in the heater assembly. The ATC ECU uses the input to prevent the formation of ice on the
evaporator.
In-car temperature sensor
The in-car temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input of cabin air
temperature. The sensor is integrated into the inlet of an electric fan, which is installed behind a grille in the fascia
outboard of the steering column. The fan runs continuously, while the ignition is on, to draw air through the grille and
across the sensor.
Sunlight sensor
The sunlight sensor consists of two diodes that provide the ATC ECU with inputs of light intensity, one as sensed
coming from the left of the vehicle and one as sensed coming from the right. The inputs are used as a measure of the
solar heating effect on vehicle occupants. The sensor is installed in the centre of the fascia upper surface.
Heater coolant temperature sensor
The heater coolant temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input related
to heater matrix coolant temperature. The sensor is installed in the casing of the heater assembly and presses against
the end tank of the heater matrix.
Ambient temperature sensor
The ambient temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input of external
air temperature. The sensor is attached to the cooling fan mounting bracket in front of the condenser.
Limit Opening pressure, bar (lbf.in2) Closing pressure, bar (lbf.in2)
Minimum 2.0 (29.0), pressure decreasing 2.3 (33.4), pressure increasing
Maximum 32 (464), pressure increasing 26 (377), pressure decreasing

AIR CONDITIONING
REFRIGERANT RECOVERY, RECYCLING AND RECHARGING 82-29
REFRIGERANT RECOVERY, RECYCLING AND RECHARGING
Refrigerant recovery, recycling and
recharging
$% 82.30.02
Recovery
1.Remove dust caps from high and low pressure
connectors.
2.Connect high and low pressure hoses to
appropriate connections.
3.Open valves on connectors.
4.Turn valves on refrigerant station to correct
positions.
Operate the refrigerant station in accordance
with the manufacturers instructions.
5.Turn Process switch to correct position.
6.Turn Main switch to 'ON'.
7.Allow station to recover refrigerant from
system.
WARNING: Refrigerant must always be
recycled before re-use to ensure that the
purity of the refrigerant is high enough for
safe use in the air conditioning system.
Recycling should always be carried out with
equipment which is design certified by
Underwriter Laboratory Inc. for compliance
with SAE J1991. Other equipment may not
recycle refrigerant to the required level of
purity.
A R134a Refrigerant Recovery Recycling
Recharging Station must not be used with
any other type of refrigerant.
Refrigerant R134a from domestic and
commercial sources must not be used in
motor vehicle air conditioning systems.
8.Close valves on refrigerant station.
9.Turn Main switch to 'OFF'.
10.Close valves on connectors.
11.Disconnect connectors high and low pressure
hoses from connectors.
12.Fit dust caps to connectors. 13.Open tap at rear of station to drain refrigerant
oil.
14.Measure and record quantity of refrigerant oil
recovered from system.
15.Close tap at rear of station.
Evacuation
WARNING: Servicing must only be carried
out by personnel familiar with both the
vehicle system and the charging and testing
equipment. All operations must be carried
out in a well ventilated area away from open
flame and heat sources.
1.Remove dust caps from high and low pressure
connectors.
2.Connect high and low pressure hoses to
appropriate connections.
3.Open valves on connectors.
4.Turn valves on refrigerant station to correct
positions.
5.Turn Process switch to correct position.
6.Turn Main switch to 'ON'.
7.Allow station to evacuate system.
Recharging
NOTE: When recharging, always make
allowance for refrigerant in the line between the
charging station and the vehicle. This is
calculated at 30 grammes/metre of charging
line. System charge weights are 700
± 25
grammes for front A/C system only and 900
±
25 grammes for combined front and rear A/C
system.
1.Close valves on refrigerant station.
2.Close valve on oil charger.
3.Disconnect yellow hose from refrigerant
station.
4.Remove lid from oil charger.
5.Pour same quantity of refrigerant oil into oil
charger as collected during recovery. If the
following components have been renewed, add
the following additional quantity of lubricating
oil:
lCondenser = 40 cm
3
lEvaporator = 40 cm3
lPipe or hose = 5 cm3/metre
lReceiver/dryer = 15 cm3.
6.Fit lid to oil charger.
7.Connect yellow hose to refrigerant station.
8.Open valve on oil charger.
9.Move pointer on refrigerant gauge to mark
position of refrigerant charge quantity.

+ CAPACITIES, FLUIDS AND
LUBRICANTS, Capacities.

AIR CONDITIONING
82-44REPAIRS
6.Remove 6 screws and 4 clips securing main
casing and remove top half of casing.
7.Loosen and release evaporator pipes unions,
release pipes and remove evaporator.
8.Remove and discard evaporator pipe 'O' rings.
Refit
1.Lubricate new 'O' rings with clean refrigerant oil
and fit to evaporator pipes
2.Position evaporator, connect pipes and tighten
unions.
3.Position main casing and secure with clips and
screws.
4.Position lower part of casing and secure with
screws.
5.Fit ducting seal
6.Secure relay to support bracket.
7.Fit insulation to TXV.
8.Fit evaporator assembly.

+ AIR CONDITIONING, REPAIRS,
Evaporator and motor assembly - rear.
Evaporator and motor assembly - rear
$% 82.26.21
Remove
1.Depressurise air conditioning system.

+ AIR CONDITIONING, REFRIGERANT
RECOVERY, RECYCLING AND
RECHARGING, Refrigerant recovery,
recycling and recharging.
2. V8 models: Remove 4 clips securing rear
exhaust heat shield and remove heat shield.
3.Remove 2 bolts securing high and low
pressure pipes, release pipes and discard 'O'
rings.
CAUTION: Always fit plugs to open
connections to prevent contamination.
4.Remove 2 bolts securing grommet flange to
body and remove flange.
5.Remove LH rear lower trim casing.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - side - loadspace.
6.Remove 5 bolts securing seat support bracket
and remove bracket.

AIR CONDITIONING
REPAIRS 82-45
7.Disconnect A/C harness multiplugs from body
harness.
8.Remove 2 clips securing ducting to A/C
assembly and release ducting. 9.Remove 4 bolts securing evaporator assembly
and remove assembly.
Refit
1.Position evaporator assembly to body fit bolts
and tighten to 16 Nm (12 lbf.ft).
2.Position ducting to evaporator assembly and
secure with clips.
3.Connect harness multiplugs.
4.Position seat support bracket, fit bolts and
tighten to 24 Nm (18 lbf.ft).
5.Fit LH rear lower trim casing.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - side - loadspace.
6.Position grommet flange and tighten bolts.
7.Lubricate new 'O' rings with clean refrigerant oil
and fit to high and low pressure pipes.
8.Position high and low pressure pipes, fit bolts
and tighten to 10 Nm (7 lbf.ft).
9. V8 models: Position exhaust heat shield and
secure with clips.
10.Repressurise air conditioning system.

+ AIR CONDITIONING, REFRIGERANT
RECOVERY, RECYCLING AND
RECHARGING, Refrigerant recovery,
recycling and recharging.

WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-9
The wiper blades are attached to the wiper arms with a clips that allow the blade to pivot. Each wiper blade comprises
a number of levers and yokes to which the rubber wiper is attached. The levers and yokes ensure that the pressure
applied by the arm spring is distributed evenly along the full length of the blade. The rubber wiper is held in the yokes
by a pair of stainless steel strips which also contribute to the even distribution of spring pressure along the blade. The
driver's side wiper blade is fitted with an aerofoil which presses the blade onto the screen at high speed. This prevents
the blade from lifting off the screen and maintains the wiping performance.
Front wash/ wipe switch
The front wash/ wipe switch is located on a stalk on the RH side of the steering column and allows the driver to control
the operation of the front wipers and the front washer pump.
Operating the washer switch provides battery voltage from fuse 19 in the passenger compartment fusebox to the
washer pump motor.
Operating the flick wipe function provides battery voltage from fuse 19 in the passenger compartment fuse box to the
high-speed brushes of the wiper motor.
Operating the intermittent function provides a battery voltage signal to the BCU. The BCU determines the wipe
interval from the variable delay switch and signals the IDM to activate the front wiper relay, which provides battery
voltage to the wiper motor.
Operating the low-speed function provides battery voltage from fuse 19 in the passenger compartment fuse box to
the low-speed brushes of the wiper motor.
Operating the high-speed function provides battery voltage from fuse 19 in the passenger compartment fuse box to
the high-speed brushes of the wiper motor

HARNESSES
86-7-12 REPAIRS
24.Remove bolt securing harness clip to LH side of
engine.
25.Disconnect camshaft sensor and oil pressure
switch multiplugs.
26.Remove engine harness. Refit
1.Position engine harness around engine.
2.Connect oil pressure switch and camshaft
sensor multiplugs.
3.Fit and tighten bolt securing harness to LH side
of engine.
4.Connect both knock sensor multiplugs.
5.Connect battery cable and solenoid cable to
starter motor.
6.Position starter heat shield and secure with
bolt.
7.Clean exhaust flange mating faces, using a
new gasket align exhaust fit nuts and tighten to
60 Nm (44 lbf.ft).
8.Remove stand(s) and lower vehicle.
9.Position harness into footwell and secure
grommet.
10.Connect ECM multiplugs.
11.Position toe board and secure with trim fixings.
12.Connect engine harness to main harness
multiplug and secure earth lead.
13.Connect EVAP solenoid multiplug.
14.Connect both fuse box multiplugs.
15.Position starter lead to fuse box and secure
screw.
16.Fit fuse box cover.
17.Position battery positive lead to battery and
secure nut.
18.Secure harness to coolant rail.
19.Position alternator cables and tighten terminal
B+ to 18 Nm (13 lbf.ft) and terminal D+ to 5 Nm
(3.7 lbf.ft)
20.Connect coolant temperature sensor multiplug.
21.Connect A/C compressor multiplug.
22.Secure harness clip to rear of LH cylinder head.
23.Connect CKP sensor multiplug.
24.Secure injector harness and connect injector
multiplugs.
25.Connect coil multiplugs.
26.Connect and secure HS
2O sensor multiplug
27.Fit upper inlet manifold.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Gasket - inlet
manifold - upper - Without Secondary Air
Injection.
28.Connect battery earth lead.

HARNESSES
REPAIRS 86-7-15
15.Disconnect multiplug from MAP sensor.
16.Disconnect 4 glow plug connectors.
17.Release nut securing battery lead to alternator
and disconnect multiplug from alternator.
18.Disconnect injector multiplug.
19.Remove 2 bolts securing harness to front of
cylinder head.
20.Disconnect multiplug from ECT sensor. 21.Disconnect multiplugs from A/C compressor,
turbocharger solenoid valve, AAP sensor and
MAF sensor.
22.Release harness clips from coolant hose and
PAS hose.
23.Note the route of the engine harness, release
from underneath of inlet manifold and remove
from engine.
Refit
1.Position harness on engine.
2.Connect multiplugs to A/C compressor,
turbocharger solenoid valve, AAP and MAF
sensors.
3.Position harness clips to coolant and PAS
hoses.
4.Connect multiplug to ECT sensor.
5.Position harness to front of cylinder head and
tighten bolts to 10 Nm (7 lbf.ft).
6.Connect injector multiplug.
7.Connect multiplug and position battery cable to
alternator and tighten nut.
8.Connect multiplug to fuel temperature sensor.
9.Connect multiplug to MAP sensor.
10.Connect glow plugs.
11.Connect CKP sensor multiplug.
12.Connect Lucar to starter solenoid.
13.Connect battery lead to starter solenoid and
tighten nut to 10 Nm (7 lbf.ft).
14.Position harness clip to coolant pipe.
15.Locate harness over bell housing and connect
multiplug to oil pressure switch.
16.Connect 2 multiplugs to EGR solenoids.
17.Connect engine harness multiplug to ECM and
main harness.
18.Connect engine harness multiplugs to fuse
box.
19.Position glow plug lead to fuse box and tighten
bolt to 3.5 Nm (2.6 lbf.ft).
20.Position battery and alternator leads to fuse
box and tighten bolts to 6 Nm (4.4 lbf.ft).
21.Fit engine compartment fuse box cover.
22.Fit battery carrier.
23.Fit engine acoustic cover.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-1
INS TRUMENTS DESCRIPTION AND OPERAT ION
Instrument pack
1Hill descent control information warning lamp
2Overspeed warning lamp
3Brake system warning lamp
4Malfunction Indicator Lamp (MIL)
5Tachometer
6Direction indicator warning lamp
7Main beam warning lamp
8Direction indicator warning lamp
9Speedometer
10SRS warning lamp
11Off road mode warning lamp
12Glow plug warning lamp
13Trailer warning lamp
14Water in fuel filter warning lamp
15Transmission high temperature warning lamp
16Seat belt warning lamp17Fuel tank level gauge
18Low fuel level warning lamp
19LCD odometer/trip meter
20Anti-theft status warning lamp
21ABS warning lamp
22Gearbox manual/sport mode warning lamp
23Alternator charge warning lamp
24ACE warning lamp
25Oil pressure warning lamp
26SLS warning lamp
27Hill descent control warning lamp
28Engine coolant temperature gauge
29High coolant temperature warning lamp
30Traction control warning lamp
31Differential lock warning lamp
32Transfer box neutral warning lamp