check engine LAND ROVER DISCOVERY 1995 Repair Manual

SFI
17
REPAIR ADD: 09/95 Refit
6.Fit a NEW filter to bracket.
NOTE: Ensure direction of flow arrow
stamped on canister is correct.
7.Position filter mounting bracket to chassis and
secure with nut and bolt.
8.Remove plugs from fuel hose ends.
9.Lubricate NEW 'O' rings with clean fuel and fit to
fuel hoses.
10.Connect fuel hoses to filter and tighten unions to
18 Nm.
CAUTION: Use two spanners when
loosening or tightening unions.
11.Remove stand(s) and lower vehicle.
12.Run the engine to check for any fuel leaks.FUEL PUMP AND GAUGE SENDER UNIT -
ADVANCED EVAPS
Service repair no - 19.45.03
A plastic fuel tank with a combined fuel pump and
gauge sender unit is fitted. The top flange of the pump
also houses a pressure sensor which is not removable
from the pump. The fuel pump is accessed through a
panel in the load space floor.
WARNING: Ensure that fuel handling
precautions given in 01 - Introduction are
strictly adhered to when carrying out
following instructions.
CAUTION: Before disconnecting any part
of fuel system, it is imperative that all dust,
dirt and debris is removed from around
components to prevent ingress of foreign matter
into fuel system.
Remove
1.Depressurise fuel system.
See fuel system -
depressurise - advanced evaps
2.Disconnect battery negative lead.
3.Check the amount of fuel in the tank. If the tank
is full, drain 2.4 US gallons (9 litres) minimum.
See fuel tank - draining - advanced evaps
4.Remove 6 screws securing tail door tread strip
and remove tread strip.
5.Remove RH luggage compartment side panel.
See CHASSIS AND BODY, Repair, rear
compartment lower trim panels

SFI
19
REPAIR ADD: 09/95
12.Using service tool LRT-19-009 loosen and
remove the metal locking ring.
13.Prise the pump from the tank opening using a
blunt instrument under the edge of the pump
flange. Once clear of the seal, tip the pump to
the right to allow fuel contained in the body of
the pump to drain into the tank.
CAUTION: Do not lift the pump from the
tank using the feed and return stubs.
14.Remove and discard seal.Refit
15.Fit NEW pump seal to tank opening.
16.Carefully lower pump into tank opening, pressing
firmly on the pump top flange to allow correct
positioning.
NOTE: Ensure location tag on pump top
flange is engaged correctly to tank
opening lip.
17.Fit locking ring and tighten to
35 Nmusing
service tool LRT-19-009.
18.Connect both fuel lines to the pump by pushing
the connectors down each line square to the
pump connection until the connectors positively
latch.
19.Connect vent hose to pressure sensor body.
20.Connect multiplugs to fuel pump and pressure
sensor.
21.Reconnect battery negative lead.
22.Refill tank with drained fuel.
23.Run the engine to check for any fuel leaks.
24.Fit access panel and secure with screws.
25.Reposition loadspace sound insulation and
carpet.
26.Fit RH luggage compartment side panel.
See
CHASSIS AND BODY, Repair, rear
compartment lower trim panels
27.Fit tail door tread strip and secure with screws.

19FUEL SYSTEM
24
REPAIRADD: 09/95 Refit
29.Fit NEW pump seal to tank opening.
30.Carefully lower pump into tank opening, pressing
firmly on the pump top flange to allow correct
positioning.
NOTE: Ensure location tag on pump top
flange is engaged correctly to tank
opening lip.
31.Fit locking ring and tighten to
35 Nmusing
service tool LRT-19-009.
32.Fit vent hose to fuel tank clips and connect to
pressure sensor.
33.With assistance, fit fuel tank into position.
34.Fit fuel tank cradle and secure with nuts and
bolts.
35.Align upper fuel tank strap and secure with nut
and bolt.
36.Fit NEW clip to fuel filler neck hose.
37.Connect fuel filler neck internal breather to tank.
38.Connect fuel filler neck hose to tank.
39.Position fuel filler neck hose clip and tighten until
head shears.
40.Connect vent line quickfit connector to
liquid/vapour separator.
41.Connect vent line hose connection.
42.Position anti-roll [sway] bar straps and secure
with nuts and bolts.
43.Remove stand(s) and lower vehicle.
44.Connect both fuel lines to the pump by pushing
the connectors down each line square to the
pump connection until the connectors positively
latches.
45.Connect multiplugs to fuel pump and pressure
sensor.
46.Reconnect battery negative lead.
47.Refill tank with drained fuel.
48.Run the engine to check for any fuel leaks.
49.Fit access panel and secure with screws.
50.Reposition loadspace sound insulation and
carpet.
51.Fit RH luggage compartment side panel.
See
CHASSIS AND BODY, Repair, rear
compartment trim panels
52.Fit tail door tread strip and secure with screws.FUEL TANK - DRAINING - ADVANCED EVAPS
Service repair no - 19.55.02
WARNING: Before removing the fuel tank
it must be drained.
WARNING: Petrol/gasoline vapour is
highly flammable and in confined spaces
is also explosive and toxic. Always have a
fire extinguisher containing FOAM, CO2, GAS or
POWDER close at hand when handling or draining
fuel. See Introduction
CAUTION: Before disconnecting any part
of fuel system, it is imperative that all dust,
dirt and debris is removed from around
components to prevent ingress of foreign matter
into fuel system.
NOTE: Assuming the fuel tank is FULL
drain the following quantities:
Renew Fuel pump = 9 Litres (2.4 US Gallons)
Renew Fuel filler neck = 22 Litres (6 US Gallons)
Renew Fuel tank = COMPLETE DRAIN
1.Depressurise fuel system.
See fuel system -
depressurise - advanced evaps
2.Disconnect battery negative lead.
3.Remove 6 screws securing tail door tread strip
and remove tread strip.
4.Remove RH luggage compartment side panel.
See CHASSIS AND BODY, Repair,

19FUEL SYSTEM
4
DESCRIPTION AND OPERATION
Injectors
The four fuel injectors are fitted between the
pressurised fuel rail and inlet manifold. Each injector
comprises of a solenoid operated needle valve and a
specially designed nozzle to ensure good fuel
atomisation.
Engine coolant temperature sensor
The coolant temperature sensor is mounted in the
thermostat housing and is immersed in the engine
coolant. The sensor is a resistive device in which the
resistance varies with temperature
Throttle housing
The throttle housing is attached to the inlet manifold
via a rubber sandwich plate and incorporates a throttle
disc which is connected to the throttle pedal via the
throttle lever and a cable.
There are two breather pipes; one either side of the
throttle disc. When the engine is running with the
throttle disc open, both pipes are subject to manifold
depression and draw crankcase fumes into the
manifold. When the throttle disc is closed, only the
pipe on the inlet manifold side of the disc is subject to
manifold depression. This pipe incorporates a
restrictor to prevent engine oil being drawn into the
engine by the substantially greater manifold
depression.
Also incorporated in the throttle housing are the
throttle potentiometer and stepper motor.
Throttle potentiometer
The throttle potentiometer is mounted in front of the
throttle housing and is directly coupled to the throttle
disc shaft.
Three wires connect the throttle potentiometer to the
ECM; a 5 volt supply to the potentiometer, an earth
return to the ECM and an output voltage to the ECM
which indicates the rate of throttle disc movement.
Stepper motor
The stepper motor is contained within the throttle
housing and operates a cam and push rod via a
reduction gear. The push rod is in direct contact with
the throttle lever and moves the throttle disc to control
idle and fast idle speed. The stepper motor maximum
movement is 3.75 revolutions accomplished in steps
of 7.5°. The reduction gear converts this into 180°of
cam movement.
The throttle lever has a throttle position setting screw
which rests on the stepper motor operating pin when
the throttle pedal is released and is used to set the
relationship between engine speed and stepper motor
position.
In the side of the throttle housing is a throttle air
bypass bleed screw to provide easier and more
sensitive setting of the stepper motor position at idle.
The stepper motor position is checked using Testbook
and should be within the range of 20 to 40 steps when
the engine is run in. If it is identified as being outside
this range it can be adjusted to within range by turning
the throttle air bypass bleed screw. It is important to
follow Testbook setting procedure when adjusting this
screw to prevent mismatching of throttle body
settings. This ensures that the stepper motor is at the
optimum position within its range for providing further
movement to compensate for changes in engine load
or temperature in accordance with signals from the
ECM
NOTE: The stepper motor and throttle
position setting screws must only be
adjusted when Testbook identifies the
requirement.

Mpi
5
DESCRIPTION AND OPERATION
Fuel pump
The electric fuel pump, located inside the fuel tank, is
a self-priming centrifugal 'wet' pump, the motor and
pump are filled with fuel.
The fuel pump supplies more fuel than the maximum
load requirement for the engine, so that pressure in
the fuel system can be maintained under all
conditions.
Fuel pressure regulator
The pressure regulator is a mechanical device
controlled by manifold depression and is mounted in
the fuel rail. The regulator ensures that fuel rail
pressure is maintained at a constant pressure
difference to that in the inlet manifold, as manifold
depression increases the regulated fuel pressure is
reduced in direct proportion.
When pressure exceeds the regulator setting excess
fuel is spill returned to the fuel tank swirl pot which
contains the fuel pick-up strainer.
Relay module
The relay module contains the main relay, fuel pump
relay, starter relay and oxygen sensor relay and is
mounted on the ECM mounting bracket.
The main relay is energised when the ignition is
switched on and supplies current to the ECM
The fuel pump relay is energised by the ECM for a
short period when the ignition is switched on, during
cranking and while the engine is running.
The starter relay is energised by the cranking signal
from the ignition switch.
This oxygen sensor relay is energised when the
ignition is switched on and supplies current to the
ECM
Intake air temperature sensor
The intake air temperature sensor is fitted in the side
of the inlet manifold and sends the ECM a signal
relating to air temperature. The ECM uses this signal
in its calculations on air flow.
Inertia switch
The fuel pump circuit incorporates an inertia switch
which in the event of sudden deceleration isolates the
power supply to the fuel pump. The inertia switch is
situated in the engine compartment on the bulkhead
and can, if tripped, be reset by depressing the central
plunger.
WARNING: Check the integrity of the fuel
system before the inertia switch is reset.
Diagnostic connector
A diagnostic connector is provided to enable
diagnosis to be carried out without disturbing the
system electrical connections and to allow the ECM's
ability to store certain faults to be utilised.
Oxygen sensor - Closed-loop emission control
The MEMS Mpi system operates a closed loop
emission system to ensure the most efficient level of
exhaust gas conversion.
An oxygen sensor fitted in the exhaust manifold
monitors the exhaust gases. It then supplies a small
voltage proportional to exhaust oxygen content to the
ECM As the air/fuel mixture weakens, the exhaust
oxygen content increases and so the voltage to the
ECM decreases. If the mixture becomes richer so the
oxygen content decreases and the voltage increases.
The ECM uses this signal voltage to determine the
air/fuel mixture being delivered to the engine, and
adjusts the injector duration to maintain the ratio
necessary for efficient gas conversion by the catalyst.
The oxygen sensor has an integral heating element to
ensure an efficient operating temperature is quickly
reached from cold. The electrical supply for the heater
element is controlled by the oxygen sensor relay.
Fuel temperature sensor
The fuel temperature sensor is inserted in the fuel rail
and measures fuel and fuel rail temperatures. During
engine cranking at high temperatures, the ECM
increases fuel supply, and opens the throttle disc via
the stepper motor to aid hot starting.

CRUISE CONTROL
1
FAULT DIAGNOSIS ROAD TEST
CAUTION: Do not engage cruise control
when vehicle is being used in low transfer
gear or reverse.
WARNING: The use of cruise control is not
recommended on winding, snow covered
or slippery roads or in heavy traffic
conditions where a constant speed cannot be
maintained.
1.Start engine, depress main control switch to
actuate cruise control system. Accelerate to
approximately 50 km/h, (30 mph), operate
'set/acc'switch, immediately release switch,
remove foot from accelerator pedal. Vehicle
should maintain speed at which'set/acc'switch
was operated.
2.Operate'set/acc'switch and hold at that
position, vehicle should accelerate smoothly until
switch is released. Vehicle should now maintain
new speed at which'set/acc'switch was
released.
3.Momentarily touch and release'set/acc'switch,
vehicle speed should increase 1.6 km/h (1 mph)
for each touch. Note that five touches will
increase speed 8 km/h (5 mph).
4.Apply'res/decel'switch while vehicle is in cruise
control mode, cruise control should disengage.
Slow to approximately 55 km/h, (35 mph)
operate'res/decel'switch, immediately release
switch and remove foot from accelerator, vehicle
should smoothly accelerate to previously set
speed. Increase speed using accelerator pedal,
release pedal, vehicle should return to previously
set speed.
NOTE: The cruise control system fitted to
the diesel engine is not as responsive as
that fitted to the petrol engine, due to the
characteristics of diesel engines. Therefore, at
speeds below approx. 65 km/h (40 mph), the
vehicle speed may drop when cruise is selected
and then slowly regain the 'set' speed.5.Operate brake pedal, cruise control system
should immediately disengage returning vehicle
to driver control at accelerator pedal. Operate
'res/decel'switch, vehicle should accelerate to
previously set speed without driver operation of
accelerator pedal.
6.Operate'res/decel'switch and allow vehicle to
decelerate to below 42 km/h, (26 mph). Operate
'res/decel'switch, cruise control system should
remain disengaged.
7.Operate'set/acc'switch below 40 km/h, (28
mph), cruise control system should remain
disengaged. Accelerate, using accelerator pedal
to above 45 km/h, (28 mph), operate'res/decel'
switch, and remove foot from accelerator pedal,
vehicle should smoothly adjust to previously
memorised speed.
8. Automatic vehicles- select neutral, system
should disengage.Manual vehicles- depress
clutch, system should disengage.
9.Cruise at 80 km/h (50 mph), declutch, select
neutral, remove foot from clutch. Operate
'res/decel'switch. Engine should rev to 5000
rev/min, cruise control disengages, engine
returns to idle.
10.Engage forward gear. Operate'res/decel'
switch. Remove foot from accelerator. Speed
should accelerate to previous set speed.
11.Depress main control switch in control system
should immediately disengage and erase
previously set speed from ECU memory.
See
Electrical Trouble Shooting Manual.
ELECTRICAL TESTS
Electrical functionality can be checked using
TestBook.
CABLE SETTING - TDi AUTOMATIC MODELS
1.An incorrectly adjusted kickdown cable can
prevent correct operation of the cruise control
system.
See AUTOMATIC GEARBOX,
Adjustment, kickdown cable adjustment.

Tdi
1
FAULT DIAGNOSIS ENGINE OVERHEATING
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Is coolant level correct?
NO - Allow engine to cool, top up level to
expansion tank seam.
YES - Continue.
2.Is drive belt tension correct?
NO -
See ENGINE, Repair, Compressor
Drive Belt
YES - Continue.
3.Is coolant in radiator frozen?
YES - Slowly thaw and drain system.
See
Adjustment, Coolant
NO - Continue.
4.Is air flow through radiator restricted or blocked?
YES - Apply air pressure from engine side of
radiator to clear obstruction.
NO - Continue.
5.Are there any external leaks, from water pump,
engine gaskets, fast idle thermostat or the heater
unit?
YES - Investigate and rectify.
See Adjustment,
Coolant
NO - Continue.
6.Are fan blades fitted correct way round, concave
side towards engine?
NO - Rectify.
YES - Continue
7.Is viscous unit operating correctly?
See
Description and operation, Viscous Fan
NO - Renew.See Repair, Viscous
Coupling, Fan Blades, Pulley and Fan
Cowl
YES - Carry out a pressure test on radiator cap
and system. Check thermostat type,
operation and correct fitting.
See Repair,
Thermostat
If pressure test leads you to suspect coolant
leakage across gaskets, go to check 10,
otherwise: Continue.8.Are the air conditioning fans operating correctly?
See Electrical Trouble Shooting Manual.
NO - Rectify.
YES - Continue.
9.Is temperature sender and gauge giving
accurate readings?
NO - Sustitute parts and compare readings.
YES - Continue.
10.Carry out cylinder pressure test to determine if
pressure is leaking into cooling system causing
over pressurising and loss of coolant.
If problem is not diagnosed, check the coolant system
for engine oil contamination and engine lubrication
system for coolant contamination.
If only the coolant system is contaminated suspect a
cylinder head gasket.
If both systems are contaminated, suspect the
radiator.
If only the lubrication system is contaminated with
coolant, suspect leakage past cylinder liner seals or
cylinder head gasket.

26COOLING SYSTEM
2
FAULT DIAGNOSIS ENGINE RUNS COLD
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Check operation of viscous unit.See
Description and operation, Viscous Fan
Is viscous unit operating correctly?
NO -
See Repair, Viscous Coupling, Fan
Blades, Pulley and Fan Cowl
YES - Continue.
2.Is thermostat correct type and operating?
See
Repair, Thermostat
If problem is not diagnosed: Continue.
3.Are the air conditioning fans operating
continuously?
YES -
See Electrical Trouble Shooting
Manual.
NO - Continue.
4.Is temperature sender and gauge giving
accurate readings? Substitute parts and
compare readings. If problem is not diagnosed
repeat tests, starting at 1.

Tdi
1
ADJUSTMENT COOLANT
Service repair no - 26.10.01
Draining
WARNING: Do not remove any caps or
plugs when the engine is hot. The cooling
system is pressurised and personal
scalding could result.
1.Remove expansion tank filler cap.
2.Disconnect bottom hose from radiator and allow
coolant to drain into a container. Ensure
container is clean if reusing coolant.
NOTE: When expansion tank has emptied,
remove thermostat housing plug to assist
drainage. Similarly when coolant level is
below top of radiator, remove radiator plug.
3.Reconnect hose after draining and tighten hose
clamp.
Refit
CAUTION: In order to expel ALL air from
the cooling system, follow the procedures
carefully.
NOTE: Refill procedure is slow but can be
accelerated by squeezing hoses to assist
removal of air from the system.
4.Add correct mix of coolant into expansion tank
until radiator is full (as seen through plug hole on
top of radiator).
See LUBRICANTS, FLUIDS
AND CAPACITIES, Information, Anti-Freeze
CAUTION: Take care to avoid excess
coolant spillage from radiator.
5.Fit radiator plug.
6.Continue adding coolant into expansion tank
until coolant appears in thermostat housing.
CAUTION: Take care to avoid excess
coolant spillage from thermostat housing.
7.Fit thermostat housing plug.
8.Check coolant in expansion tank is level with
indicator post. Add more coolant if necessary.
9.Start engine and run for 5 minutes.
10.Allow engine to cool, check coolant level in
expansion tank; top up to level indicator post if
necessary.
11.Fit expansion tank filler cap.

Tdi
1
REPAIR VISCOUS COUPLING, FAN BLADES, PULLEY AND
FAN COWL
Service repair no - 26.25.03/05
Viscous coupling -Remove1to3
Fan blades -Remove1to4
Fan cowl -Remove1to3
Fan pulley -Remove1to6
Remove
WARNING: Disconnect battery negative
terminal to prevent engine being started
before removing or adjusting drive belt.
1.Slacken nut securing viscous coupling/fan blade
assembly to pulley.
NOTE: Nut securing viscous unit to pulley
has a left hand thread. Release by turning
clockwise when viewed from front of
viscous unit.
2.Drop viscous unit and fan assembly into bottom
of cowling
3.Remove two fixings clips from top of cowling and
lift cowling complete with viscous unit and fan
out of lower mountings.
4.Remove fan blades from viscous coupling if
necessary.
5.Remove serpentine drive belt and, if fitted, air
conditioning compressor belt.
6.Remove pulley fixings, remove pulley.
NOTE: The serpentine belt is removed by
using a hexagonal socket and tommy bar
on the auto-tensioning pulley nut. Whilst
tensioning the device the belt can be removed.
7.Reverse removal procedure. Ensure fan blades
are fitted correctly. Fan is marked 'front' and
should be fitted with word 'front' closest to
radiator. Tighten to
30 Nm.
8.Refit drive belt.See ENGINE, Repair, Drive
Belt
THERMOSTAT
Service repair no - 26.45.01
Remove
1.Partially drain cooling system, until coolant level
is below thermostat housing.
2.Disconnect hose from thermostat housing.
3.Disconnect electrical connections to water
temperature switch.
4.Remove outlet elbow.
5.Withdraw thermostat.
Test
6.Note rating of thermostat is 88°C. Place
thermostat in a container half full of water. Heat
water, observe temperature at which thermostat
begins to open. Thermostat is satisfactory if its
open between 85°C and 89°C.
Refit
7.Insert thermostat with jiggle pin/vent hole upper
most (12 o'clock position) .
8.Fit the outlet elbow and new joint washer.
Tighten to
28 Nm.
9.Reverse removal procedure. 1 to 3.
10.Check for coolant leaks around all connections
and joint faces.