ac compre LAND ROVER DISCOVERY 2002 Repair Manual

ENGINE MANAGEMENT SYSTEM - V8
18-2-10 DESCRIPTION AND OPERATION
Connector 4 (C0637): This connector contains 40 pins and facilitates use of TestBook via the Diagnostic connector.
Also contained in this connector is the Malfunction Indicator Lamp (MIL), this instrument panel lamp informs the driver
of concerns within the engine management system.
Pin out details connector C0637
42 Idle air control valve open Output, signal PWM 12-0V
43 Idle air control valve close Output, signal PWM 12-0V
44 ECT sensor signal Output, signal PWM 0-12V
45 CKP sensor earth screen Earth 0V
46 CKP sensor signal Earth reference 0V
47 Not used - -
48 KS, LH bank earth Earth 0V
49 KS, LH bank signal Input, signal Analogue
50 Not used - -
51 Not used - -
52 Not used - -
Pin No. Function Signal type Reading
1 Not used - -
2 Not used - -
3 Not used - -
4 Not used - -
5 Not used - -
6 Not used - -
7 Not used - -
8 Low fuel level Input, signal Active high
9 Fuel tank pressure sensor (NAS vehicles with
vacuum type, EVAP system leak detection
capability only)Output, reference 5V
10 Not used - -
11 Not used - -
12 Analogue fuel level (NAS vehicles with positive
pressure type, EVAP system leak detection only)Input, signal 0-5V
13 Not used - -
14 Fuel tank pressure sensor (NAS vehicles with
vacuum type, EVAP system leak detection
capability only)Input, signal Analogue 0-5V
15 Not used - -
16 ATC compressor request Input, signal Active low
17 Engine speed output Output, signal PWM 0-5V
18 Not used - -
19 Not used - -
20 Malfunction indicator lamp 'ON' Output Switched earth
21 Not used - -
22 Vehicle speed signal (VSS) Input, signal PWM 0-12V
23 Not used - -
24 Not used - -
25 Not used - -
26 Not used - -
27 Not used - -
28 Not used - -
29 ATC compressor relay Output Switched earth
30 Not used - - Pin No. Function Signal type Reading

ENGINE MANAGEMENT SYSTEM - V8
18-2-40 DESCRIPTION AND OPERATION
Air Temperature Control (ATC) request
The ATC request comes via the ATC switch located in the facia panel. When the driver operates the switch it acts as
a request from the ATC ECU to engage the ATC clutch to drive the system.
During periods of high driver demand such as hard acceleration or maximum rev/min the ATC clutch will be disabled
for a short time. This is to reduce the load on the engine.

+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Description.
Input/Output
The operation of the ATC request is via a switch being connected to earth. Voltage is supplied via pin 38 of connector
C0637 of the ECM, at the point at when the switch is pressed the connection is made and the ATC clutch is engaged.
The ATC request can fail as follows:
lOpen circuit.
lShort circuit to voltage supply.
lShort circuit to vehicle earth.
lWiring loom fault.
In the event of an ATC request failure, the ATC system does not work.
Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by
TestBook.
ATC compressor clutch relay
The ATC compressor clutch relay is located in the engine compartment fuse box. It is a four pin normally open relay.
The relay must be energised to drive the ATC compressor clutch.
P Code J2012 Description Land Rover Description
P1535 Air conditioning compressor request
malfunctionATC requested when not in standby mode

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-41
Input/Output
The ECM provides the earth for the relay coil to allow the relay contacts to close and the ATC clutch drive to receive
battery voltage. The ECM uses a transistor as a switch to generate an open circuit in the earth path of the relay coil.
When the ECM opens the earth path, the return spring in the relay will pull the contacts apart to shut down the ATC
clutch drive.
Input to the ATC clutch relay switching contacts is via fuse 6 located in the engine compartment fuse box. The relay
coils are supplied with battery voltage from the main relay, also located in the engine compartment fuse box. The earth
path for the relay coil is via pin 29 of the ECM C0657 connector. When the relay is energised the output from the
switching contacts goes directly to the ATC compressor clutch.
The ATC clutch relay can fail in the following ways:
lRelay open circuit.
lShort circuit to vehicle supply.
lShort circuit to vehicle earth.
lBroken return spring.
In the event of an ATC clutch relay failure, the ATC does not work.
Should a malfunction of the component occur, the following fault codes may be evident and can be retrieved by
TestBook.
P Code J2012 Description Land Rover Description
P1536 Air conditioning compressor request range/
performanceATC compressor clutch relay open circuit
P1537 Air conditioning compressor request low input ATC compressor clutch relay short to earth
P1538 Air conditioning compressor request high input ATC compressor clutch relay short to battery supply

FUEL DELIVERY SYSTEM - TD5
19-1-8 DESCRIPTION AND OPERATION
The five injectors are located in the cylinder head, adjacent to the camshaft, with the nozzle of each injector protruding
directly into the cylinder. Each injector is sealed into the cylinder head with an 'O' ring and a copper washer and
secured with a clamp and bolt.
Each injector is operated mechanically by an overhead camshaft and rocker and electrically by a solenoid controlled
by the ECM. Each injector is supplied with pressurised fuel from the pump via the regulator housing and internal
drillings in the cylinder head.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.
The solenoid housing is secured to the injector body with two cap screws and is a sealed unit with a two pin electrical
connector on its top face.
The injector body is machined from a forging. The body has a machined central bore which locates the push rod. A
thread on the outer diameter provides the attachment for the nozzle cap nut. The body also provides attachment for
the solenoid housing.
The injector push rod is operated from the rocker and cam assembly by a socket. The push rod is located in the
housing bore and retained in its extended position by a push rod return spring. The powerful spring ensures that the
push rod socket is always in contact with the rocking lever and the cam.
The lower part of the injector housing locates the spring loaded nozzle. The nozzle is retained in the housing by a
nozzle cap nut which is screwed onto the housing. The nozzle cap nut has four holes around its circumference which
connect to the fuel return drilling in the cylinder head. The injector housing has ports located above the nozzle cap
nut which connect with the fuel delivery drilling in the cylinder head. An 'O' ring seals the injector in the machined
location in the cylinder head and a copper washer seals the injector from the combustion chamber.
The injectors are supplied with pressurised fuel from the fuel pump, via the pressure regulator housing and internal
drillings in the cylinder head. Each injector sprays fuel directly into the cylinder at approximately, 1500 bar (22000
lbf.in
2) on pre EU3 models and 1750 bar (25500 lbf.in2) on EU3 models, atomising the fuel and mixing it with intake
air prior to combustion.
The camshaft and rocker arrangement depresses the push rod which pressurises the fuel within the injector. When
the injector is required to inject fuel into the cylinder, the ECM energises the solenoid which closes a valve within the
solenoid housing. The closure of the valve stops the fuel entering the return line to the pump, trapping it in the injector.
The compression of the fuel by the push rod causes rapid pressurisation of the fuel which lifts the injector nozzle,
forcing the fuel into the cylinder at high pressure. The ECM controls the injection timing by altering the time at which
the solenoid is energised and the injection period by controlling the period for which the solenoid is energised.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

MANIFOLDS AND EXHAUST SYSTEMS - TD5
DESCRIPTION AND OPERATION 30-1-3
Description
General
The diesel engine has the inlet manifold attached to the right hand side of the engine and the exhaust manifold
attached to the left hand side of the engine. The inlet manifold directs cooled compressed air from the turbocharger
and intercooler into the cylinders, where it is mixed with fuel from the injectors. Exhaust gases from the exhaust
manifold can also be directed into the inlet manifold via a pipe from the exhaust manifold and an Exhaust Gas
Recirculation (EGR) valve on the inlet manifold. The exhaust manifold allows combustion gases from the cylinders to
leave the engine where they are directed into the exhaust system and turbocharger.
The exhaust system is attached to the turbocharger and is directed along the underside of the vehicle to emit exhaust
gases from a tail pipe at the rear of the vehicle. A silencer is installed midway along the system and a second tail
silencer is located at the rear of the vehicle.
Inlet manifold
The inlet manifold is a one piece aluminium casting. The manifold is secured to the cylinder head with two studs and
flanged nuts and eight flanged bolts. A one piece laminated gasket seals the manifold to the cylinder head.
Four threaded bosses on the manifold provide for the attachment of the fuel cooler. The fuel cooler is secured to the
manifold with four bolts. A boss with two threaded holes allows for the attachment of the combined intake air
temperature/pressure sensor. The sensor is secured to the manifold with two screws and sealed with a gasket.
At the forward end of the manifold, a machined face and four threaded holes provide for the attachment of the EGR
valve. The valve is sealed to the manifold with a gasket.

+ EMISSION CONTROL - Td5, DESCRIPTION AND OPERATION, Emission Control Systems.
Exhaust manifold
The exhaust manifold is made from cast iron. The manifold has five ports, one from each cylinder, which merge into
one flanged outlet connection positioned centrally on the manifold.
The manifold is attached to the cylinder head with ten studs and flanged nuts. A laminated metal gasket seals the
manifold to the cylinder head. The flanged outlet on the manifold provides the attachment for the turbocharger, which
is attached with three studs and flanged nuts and sealed with a metal laminated gasket.
A second flanged outlet, located at the forward end of the manifold, provides attachment for the EGR pipe. The EGR
pipe is secured to the manifold with two cap screws and connected to the EGR valve mounted on the inlet manifold.
There is no gasket used between the pipe and the exhaust manifold.

+ EMISSION CONTROL - Td5, DESCRIPTION AND OPERATION, Emission Control Systems.
Exhaust system
The exhaust system comprises a front pipe, an intermediate pipe which incorporates a silencer and a tail pipe
assembly which also has a silencer. The exhaust system is constructed mainly of 63 mm (2.48 in) diameter extruded
pipe with a 1.5 mm (0.06 in) wall thickness. All pipes are aluminized to resist corrosion and the silencers are fabricated
from stainless steel sheet.

MANIFOLDS AND EXHAUST SYSTEMS - TD5
REPAIRS 30-1-7
11.Remove 2 nuts and 8 bolts securing inlet
manifold to cylinder head.
12.Disconnect multiplugs from turbocharger
pressure sensor, ECT sensor, AAP sensor,
MAF sensor, A/C compressor and fuel injector
harness.
13.Remove 2 bolts securing harness to camshaft
carrier.
Note: Engine with EGR cooler illustrated.
14.Release harness from engine and inlet
manifold.
15.Remove inlet manifold and gasket. Refit
1.Clean inlet manifold and mating faces.
2.Fit new gasket.
3.Fitinlet manifold and, working from the centre
outwards, tighten nuts and bolts to 25 Nm (18
lbf.ft).
4.Position harness to sensors and connect
multiplugs.
5.Tighten bolts securing harness clip to camshaft
carrier to 9 Nm (7 lbf.ft).
6.Clean dip stick tube and fit new 'O' ring.
7.Fit dip stick tube and tighten bolt to 9 Nm (7
lbf.ft).
8.Connect leads to glow plugs.
9.Fit alternator support bracket and tighten bolts
to 45 Nm (33 lbf.ft).
10.Position fuel cooler and tighten bolts to 25 Nm
(18 lbf.ft).
11.Fit new gasket, position EGR valve and tighten
bolts to 9 Nm (7 lbf.ft).
12.Connect multiplug to MAP sensor.
13.Fit upper fan cowl.
14.Fit engine acoustic cover.
15.Connect battery earth lead.
16.Fit battery cover.

MANIFOLDS AND EXHAUST SYSTEMS - TD5
30-1-8 REPAIRS
Gasket - exhaust manifold
$% 30.15.12
Remove
Note: The following procedure covers engines
fitted with or without an EGR cooler. The EGR
cooler is bolted to the front of the cylinder head.
1.Remove turbocharger.

+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Turbocharger.
2. Models with air conditioning: Remove
auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
3. Models with air conditioning: Remove 4 bolts
securing compressor and move to one side.
4.Remove and discard 2 Allen screws securing
EGR pipe to exhaust manifold.
Note: Engine with EGR cooler illustrated.5.Remove 10 nuts securing exhaust manifold to
cylinder head.
6.Remove exhaust manifold and gasket.
Refit
1.Clean exhaust manifold and mating faces.
2.Fit new gasket.Fit exhaust manifold and,
working from the centre outwards, tighten nuts
to 25 Nm (18 lbf.ft) .
3. Models with air conditioning:
Positioncompressor and tighten bolts to 25 Nm
(18 lbf.ft).
4.Position EGR valve pipe, fit new Allen screws
and tighten to 9 Nm (7 lbf.ft).
5.Fit turbocharger.
+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Turbocharger.
6. Models with air conditioning: Fit auxiliary
drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.

CLUTCH - TD5
33-1-8 DESCRIPTION AND OPERATION
The dual mass flywheel is used to insulate the gearbox from torsional and transient vibrations produced by the engine.
The flywheel comprises primary and secondary flywheels with the drive between the two transferred by a torsional
damper which comprises four coil springs. The springs are located in the inside diameter of the primary flywheel. Two
of the springs are of smaller diameter and fit inside the larger diameter springs.
The primary flywheel locates the ring gear and is attached to the crankshaft flange with eight bolts. The two pairs of
coil springs are located in a recess in the flywheel between two riveted retainers. A roller bearing is pressed onto the
central boss of the primary flywheel and retained with a riveted plate. The bearing provides the mounting for the
secondary flywheel.
The secondary flywheel comprises two parts; an outer flywheel which provides the friction surface for the clutch drive
plate and an inner drive plate which transfers the drive from the primary flywheel, via the coil springs, to the outer
flywheel. The two components of the secondary flywheel are secured to each other with rivets. The inner drive plate
is located between the two pairs of coil springs and can rotate on the ball bearing in either direction against the
combined compression force of the four coil springs. Under high torque loading conditions the secondary flywheel can
rotate in either direction up to 70
° in relation to the primary flywheel.
The operating face of the secondary flywheel is machined to provide a smooth surface for the drive plate to engage
on. Three dowels and six studs and nuts provide for the location and attachment of the pressure plate.
Pressure plate
1Leaf spring
2Drive plate
3Pressure plate
4Cover
5Diaphragm
6Rivet

CLUTCH - V8
DESCRIPTION AND OPERATION 33-2-9
The drive plate is of the spring centred type and is sandwiched between the pressure plate and the flywheel. The drive
plate has a splined hub which engages with the splines on the primary drive shaft from the gearbox. The hub is located
in an inner plate which contains six compression damper springs. A spring retainer plate and a disc adaptor are
secured together with stop pins which limit the angular deflection of the disc adaptor. Engine power is transmitted from
the disc adaptor to the damper springs. The damper springs then transfer the power to the retainer plate and the hub.
Friction washers are located between the hub, retainer plate and disc adaptor and provide further damping.
A spring steel plate is riveted to the disc adaptor and provides the attachment surface for the drive plate friction
material. The friction material comprises discs which are secured with rivets to each side of the plate. The rivets are
installed through recessed holes in the disc and emerge in recessed holes in the opposite disc. The drive plate is 267
mm (10.5 in) diameter and has a friction material manufactured from APTEC T385.

TRANSFER BOX - LT230SE
OVERHAUL 41-43
4.Remove 3 bolts securing differential lock
selector housing and remove housing.
5.Remove and discard 'O' ring from selector
housing.
6.Remove Allen plug and remove detent spring
and ball.
7.Remove differential lock warning lamp switch
and locknut.
Note: Locknut is only fitted to switches up to 03
MY, a modified switch and sealing washer is
fitted from 03 MY onwards.
8.03 MY onwards: Remove differential lock
warning lamp switch from end of front output
shaft housing, discard sealing washer.
9.Compress differential lock selector fork spring
and remove retaining clips from each end of
spring.
10.Withdraw differential lock selector shaft from
front output housing, recover spring and
remove selector fork.
Note: Carry out the following operations for all
transfer boxes.11.Position tool LRT-51-003 to output shaft drive
flange, remove and discard nut, steel and felt
washers; remove output shaft drive flange.
12.Using a copper mallet, drive output shaft from
housing, recover bearing spacer.
13. If fitted: Noting its fitted position, remove dog
clutch from output shaft.