warning LAND ROVER DISCOVERY 2002 Repair Manual

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-39
Hill Decent Control (HDC)
Refer to Brakes for description of the hill descent control.

+ BRAKES, DESCRIPTION AND OPERATION, Description.
High/Low ratio switch
Refer to Transfer Box for description of the high/ low ratio switch transfer box components.

+ TRANSFER BOX - LT230SE, DESCRIPTION AND OPERATION, Description.
Malfunction Indicator Lamp (MIL)/ service engine soon warning lamp
The MIL/ service engine soon warning lamp is located in the instrument cluster. It illuminates to alert the driver to
system malfunctions. Service engine soon warning lamp is the name for this warning lamp in NAS only, it is called
MIL in all other markets.
During ignition a self-test function of the lamp is carried out. The lamp will illuminate for 3 seconds then it will
extinguish if no faults exist.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
Input/Output
The MIL is supplied with battery voltage from the instrument cluster. When the ECM detects a fault, it provides an
earth path to illuminate the MIL. Output to the MIL is via pin 20 of connector C0637 of the ECM.

ENGINE MANAGEMENT SYSTEM - V8
18-2-50 DESCRIPTION AND OPERATION
In the case of a VSS failure on vehicles with automatic gearboxes, the ECM applies default values derived from the
EAT ECU. There are no default values for manual gearbox vehicles.
The VSS can fail in the following ways:
lWiring short circuit to vehicle supply.
lWiring short circuit to vehicle earth.
lWiring open circuit.
In the event of a VSS failure, any of the following symptoms may be observed:
lMIL illuminated after 2 driving cycles (NAS only).
lVehicle speed limiting disabled (manual transmission vehicles only).
lSLABS/HDC warning lamp on and audible warning.
Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by
TestBook:
Rough road signal
When the vehicle travels across rough terrain, or on rough roads instability becomes evident in the drive train. The
ECM could interpret these vibrations as a 'false misfire'. To counteract this 'false misfire' the SLABS ECU generates
a rough road signal, sends it to the ECM so that the ECM can suspend misfire detection for as long as the vehicle is
travelling on the 'rough road'.
Function
Input for the rough road signal is measured via pin 34 of connector C0637 of the ECM. The SLABS ECU generates
a PWM signal that varies in accordance with changing road conditions. The rough road PWM signal operates at a
frequency of 2.33 Hz
± 10%. The significance of changes in the PWM signal are shown in the following table:
The rough road signal can fail in the following ways:
lHarness or connector damage
lSLABS failure — wheel speed sensor
A rough road signal failure may be evident from the following:
lHDC / ABS warning light on
P Code J2012 Description Land Rover Description
P0500 Vehicle speed sensor malfunction VSS short or open circuit
P0501 Vehicle speed sensor range/performance VSS implausible
PWM signal Indication
<10% Electrical short circuit to ground
25% ± 5 % Smooth road
50% ± 5 % SLABS error
75% ± 5% Rough road
>90% Electrical short circuit to battery voltage

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-51
Should a malfunction of the rough road signal occur, the following fault codes may be evident and can be retrieved
by TestBook:
Hill Descent Control (HDC) signal
The ECM transmits throttle angle, engine torque, engine identification (Td5 or V8), and transmission type (automatic
or manual) data to the SLABS ECU to support the Hill Descent Control system. The information is transmitted via a
0 – 12V pulse width modulated (PWM) signal at a frequency of 179.27 Hz.
Function
The HDC signal output from the ECM is via pin 29 of connector C0636. The ECM generates a PWM signal that varies
in pulse width in accordance with changing throttle angle or engine torque. The throttle angle data is transmitted on
pulses 1, 3, 5 and 37. The engine torque data is transmitted on pulses 2,4,6 and 38. The engine and transmission
information is transmitted on pulse 39. A synchronising pulse is transmitted after every 39th pulse.
The HDC signal can fail in the following ways:
lHarness or connector damage
A HDC signal failure may be evident from the following:
lHDC / ABS warning light on
lHDC inoperative
lAudible warning
Should a malfunction of the HDC signal occur, the following fault codes may be evident and can be retrieved by
TestBook:
Low fuel level signal
When the fuel level in the fuel tank becomes low enough to illuminate the low fuel level warning lamp in the instrument
cluster, the instrument cluster generates a low fuel level signal. If the low fuel level signal is present during the ECM
misfire detection function the ECM can use it to check for a 'false misfire'.
Conditions
The fuel sender generates the low fuel level signal when the fuel sender resistance is greater than 158
± 8 ohms.
P Code J2012 Description Land Rover Description
P1590 ABS rough road signal circuit malfunction Hardware is OK, but SLABS ECU is sending an error
signal
P1591 ABS rough road signal circuit low Signal from SLABS ECU short circuit to earth
P1592 ABS rough road signal circuit high Signal from SLABS ECU short circuit to vehicle battery
supply
P Code J2012 Description Land Rover Description
P1663 Throttle angle/Torque signal circuit malfunction SLABS HDC link open circuit
P1664 Throttle angle/Torque signal circuit low SLABS HDC link short circuit to ground
P1665 Throttle angle/Torque signal circuit high SLABS HDC link short circuit to battery voltage

ENGINE MANAGEMENT SYSTEM - V8
18-2-52 DESCRIPTION AND OPERATION
Function
The illumination of the low fuel level warning lamp in the instrument cluster triggers the low fuel level signal to be sent
to the ECM. This signal is processed via pin 8 of connector C0637 of the ECM.
Should a misfire occur while the fuel level is low, the following fault code may be evident and can be retrieved by
TestBook.
Coolant temperature gauge signal
The ECM controls the temperature gauge in the instrument cluster. The ECM sends a coolant temperature signal to
the temperature gauge in the instrument cluster in the form of a PWM square wave signal.
The frequency of the signal determines the level of the temperature gauge.
Conditions
The ECM operates the PWM signal under the following parameters:
l-40
°C (-40 °F) = a pulse width of 768 µs.
l140
°C (284 °F) = a pulse width of 4848 µs.
Function
The coolant temperature signal is an output from the ECM to the instrument cluster. The coolant temperature signal
is generated via pin 44 of connector C0636 of the ECM.
The coolant temperature signal can fail in the following ways:
lWiring short circuit to vehicle supply.
lWiring short circuit to vehicle earth.
lWiring open circuit.
In the event of a coolant temperature signal failure any of the following symptoms may be observed:
lCoolant temperature gauge will read cold at all times.
lCoolant temperature warning lamp remains on at all times.
Controller Area Network (CAN) system
The controller area network (CAN) system is a high speed serial interface between the ECM and the Electronic
Automatic Transmission (EAT) ECU. The CAN system uses a 'data bus' to transmit information messages between
the ECM and the EAT ECU. Because there are only two components in this CAN system, one will transmit information
messages and the other will receive information messages, and vice-versa.
Conditions
The CAN system is used by the EAT ECU and the ECM for transmission of the following information:
lGearshift torque control information.
lEAT OBD information.
lMIL request.
lVehicle speed signal.
lEngine temperature.
lEngine torque and speed.
lGear selected.
lGear change information.
lAltitude adaptation factor
lAir intake temperature
lThrottle angle / pedal position
P Code J2012 Description Land Rover Description
P1319 Misfire detected at low fuel level Misfire detected with low fuel level

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-57
Description - cruise control
General
All markets have a common cruise control system. The cruise control system, when activated, regulates vehicle
speed. The system consists of an electrical sub-system and a mechanical sub-system.
The electrical sub-system consists of the following components:
lCruise control master switch (on/off switch).
lSET+ switch.
lRES switch.
lCruise control ECU.
lVacuum pump assembly.
lBrake pedal switch.
lClutch pedal switch (manual gearbox only).
lSLABS ECU (speed signal).
lBCU (brake pedal switch and automatic gearbox gear selector lever position signal).
The mechanical sub-system consists of the following components:
lPneumatic actuator.
lVacuum pump.
The cruise control ECU controls the cruise control system. It is located on the right hand A post.
The system has diagnostic capabilities through TestBook.
WARNING: To avoid the risk of losing control of the vehicle, do not use cruise control on winding, snow
covered or slippery roads, or in traffic conditions where a constant speed cannot be safely maintained. In
these conditions and at any time the system is not being used, ensure the cruise control switch is OFF.
Cruise control master switch
The cruise control master switch switches the system on and off. When the cruise control master switch is on, an
LED within the switch illuminates. If the cruise control master switch is off, cruise control will not operate. The switch
provides a 12 Volt feed to the cruise control ECU.
The cruise control master switch is located on the instrument panel near the steering column.

ENGINE MANAGEMENT SYSTEM - V8
18-2-74 REPAIRS
5.Disconnect multiplug from ECT sensor.
6.Remove sensor from inlet manifold and discard
sealing washer.
Refit
1.Clean sealant from threads in manifold.
2.Apply Loctite 577 to sensor threads.
3.Fit new sealing washer to ECT sensor and
tighten sensor to 10 Nm (7 lbf.ft).
4.Connect multiplug to ECT sensor.
5.Position alternator, fit bolts and tighten to 45
Nm (33 lbf.ft).
6.Fit auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
7.Top up cooling system.
8.Connect battery earth lead.
9.Fit battery cover and secure with fixings.
Sensor - crankshaft position (CKP)
$% 18.30.12
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.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.
4.Release fixings and remove underbelly panel.
5.Release CKP sensor multiplug from bracket.
6.Remove 2 bolts securing CKP sensor heat
shield and position aside.
7.Remove 2 nuts securing CKP sensor, remove
2 spacers, CKP sensor and sensor mounting.
8.Disconnect CKP sensor multiplug from engine
harness.
Refit
1.Ensure all components are clean.
2.Connect CKP sensor multiplug to engine
harness.
3.Fit sensor mounting, CKP sensor, 2 spacers
and tighten CKP sensor retaining nuts to 6 Nm
(5 lbf.ft).

ENGINE MANAGEMENT SYSTEM - V8
18-2-76 REPAIRS
Sensor - camshaft position (CMP)
$% 18.30.24
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.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.
4.Release fixings and remove underbelly panel.
5.Remove engine oil filter.

+ ENGINE - V8, REPAIRS, Filter - oil.
6.Disconnect engine harness from CMP sensor
and release CMP sensor multiplug from
bracket.
7.Remove bolt from clamp securing CMP sensor
to timing gear cover.
8.Remove clamp and CMP sensor. Discard 'O'
ring from CMP sensor.
Refit
1.Ensure CMP sensor is clean, fit new 'O' ring
and sensor to cover.
2.Fit clamp to CMP sensor and tighten bolt to 8
Nm (6 lbf.ft).
3.Fit sensor multiplug to bracket and connect
engine harness to multiplug.
4.Fit engine oil filter.

+ ENGINE - V8, REPAIRS, Filter - oil.
5.Fit underbelly panel and secure with fixings.
6.Lower vehicle and connect battery earth lead.
7.Fit battery cover and secure with fixings.
Knock sensor (KS)
$% 18.30.28
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.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.
4.Remove fixings securing underbelly panel and
remove panel.
5.Disconnect multiplug from KS.
6.Remove nut securing KS to cylinder block and
remove KS.
Refit
1.Clean mating faces of KS and cylinder block.
2.Fit KS to cylinder block and tighten nut to 22
Nm (16 lbf.ft).
3.Connect multiplug to KS.
4.Fit underbelly panel and secure with fixings.
5.Remove stand(s) and lower vehicle.
6.Connect battery earth lead.
7.Fit battery cover and secure the fixings.

FUEL DELIVERY SYSTEM - TD5
DESCRIPTION AND OPERATION 19-1-3
Description
General
The fuel delivery system comprises a fuel tank, fuel pump, fuel pressure regulator, five injectors and a fuel filter. The
system is controlled by the Engine Control Module (ECM) which energises the fuel pump relay and controls the
operation and timing of each injector solenoid.
Unlike other Diesel engines, the Td5 engine has no injection pump. The diesel direct injection system receives fuel
at pressure from a two stage fuel pump located in the fuel tank. The system incorporates a fuel return to the fuel pump,
via a fuel cooler attached to the inlet manifold and a fuel filter. A fuel pressure regulator is located in a housing on the
rear of the cylinder head. The regulator maintains the fuel delivered to the injectors at a constant pressure and returns
excess fuel back to the fuel filter and pump via the fuel cooler.
A fuel filter is positioned on the chassis to the right of the fuel tank. The fuel feed and return to and from the engine
passes through the filter. The filter also incorporates a water sensor which illuminates a warning lamp in the
instrument pack.
A moulded fuel tank is located at the rear underside of the vehicle between the chassis longitudinals. The tank
provides the attachment for the fuel pump and fuel gauge sender unit which is located inside the tank.
Fuel tank and breather
The fuel tank and breather system is a major part of the fuel delivery system. The fuel tank and breathers are located
at the rear of the vehicle between the chassis longitudinals.
Fuel tank
The moulded fuel tank is made from High Molecular Weight (HMW) High Density Polyethylene (HDPE). The diesel
tank is manufactured using a proportion of recycled plastic.
The tank is retained in position by a metal cradle which is secured to the chassis with two nut plates and bolts at the
rear and a stud plate and two nuts at the front. A strap above the tank is bolted to the chassis and restrains the tank
from moving upwards. The fuel tank has useable capacity of approximately 95 litres (25 US Gallons).
An aperture in the top surface of the tank allows for the fitment of the fuel pump and fuel gauge sender unit which is
retained with a locking ring.
A reflective metallic covering is attached to the tank with two scrivets to shield the tank from heat generated by the
exhaust system.
The fuel filler is located in the right hand rear quarter panel, behind an access flap. The flap is opened electrically
using a switch on the fascia which operates a release solenoid.
The filler is closed by a threaded plastic cap which screws into the filler neck. The cap has a ratchet mechanism to
prevent overtightening and seals against the filler neck to prevent the escape of fuel vapour. The filler cap has a valve
which relieves fuel pressure to atmosphere at approximately 0.12 to 0.13 bar (1.8 to 2.0 lbf.in
2) and opens in the
opposite direction at approximately 0.04 bar (0.7 lbf.in2) vacuum.
A moulded filler tube, made from HMW HDPE, connects the filler to the tank via a flexible hose. The filler tube is
connected at its top end behind the filler flap.

FUEL DELIVERY SYSTEM - TD5
19-1-10 DESCRIPTION AND OPERATION
Water sensor
The water sensor has a three pin electrical connector. When the sensor detects water in the filter it illuminates a
warning lamp in the instrument pack .

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
The water sensor attachment thread has a slot machined down one side. The filter can be purged of water by partially
unscrewing the sensor which aligns the slot in the threads with a corresponding hole in the sensor. When aligned,
water and fuel can flow down the slot and flows from a small cast tube on the side of the sensor. Re-tightening the
sensor misaligns the slot and stops the flow of fuel.
The water sensor receives a battery supply from the fuel pump relay in the engine compartment fusebox on one of
the electrical connector pins. The two remaining pins are connected to the instrument pack and an earth header joint.
The sensor operation uses the measurement of resistance between two electrodes submerged in the fuel and
activated by the presence of water.
When the ignition is moved to position II the warning lamp will illuminate for approximately two seconds to check
warning lamp functionality. TestBook can also illuminate the warning lamp to check its functionality.
When the filter is full with fuel and no water is present the resistance of the Diesel fuel will show a reading of 15 mA
maximum on the feed wire to the instrument pack. This current will not illuminate the water sensor warning lamp in
the instrument pack. When sufficient water surrounds both electrodes the resistance of the water will show a reading
of 130 mA maximum. This will supply sufficient voltage to the instrument pack to illuminate the warning lamp to alert
the driver to the presence of water in the fuel system.

FUEL DELIVERY SYSTEM - TD5
ADJUSTMENTS 19-1-13
ADJUST ME NTS
Fuel system purging
$% 19.50.07
If the vehicle runs out of fuel, or the fuel level is so
low that the fuel system draws air into the fuel rail,
the fuel rail will need to be purged before the engine
will start. This can be achieved by following the
procedure below.
If this procedure is carried out on a vehicle that
has not run out of fuel or otherwise drawn air into
the fuel rail, it can lead to the engine flooding and
failing to start.
Purge
1.Turn the ignition switch off and wait 15
seconds.
2.Turn the ignition switch to position II and wait 3
minutes (this ensures that the fuel system
purges all the air from the fuel rail within the
cylinder head).
3.Fully depress the throttle pedal.
4.Keeping the throttle pedal fully depressed,
crank the engine.
5.As soon as engine speed exceeds 600 rev/min,
release the throttle pedal and the ignition
switch.The engine must not be cranked
continuously for more than 30 seconds at
any one time.
6.If the engine fails to start, repeat the above
procedure.
Fuel tank - drain
$% 19.55.02
Drain
1.Disconnect both leads from battery.
WARNING: Always disconnect the negative
lead first. Disconnection of the positive lead
while the negative lead is connected could
result in a short circuit through accidental
grounding and cause personal injury.
2.Remove fuel pump.

+ FUEL DELIVERY SYSTEM - Td5,
REPAIRS, Pump - fuel.
3.Using a fuel recovery appliance, drain the fuel
from the tank into a sealed container. Follow
the manufacturers instructions for the
connection and safe use of the appliance.
Refill
1.Fit fuel pump.

+ FUEL DELIVERY SYSTEM - Td5,
REPAIRS, Pump - fuel.
2.Connect battery leads, positive terminal first.