2002 LAND ROVER DISCOVERY earth

ENGINE MANAGEMENT SYSTEM - TD5
DESCRIPTION AND OPERATION 18-1-43
Air Conditioning (A/C)
The ECM controls operation of the A/C compressor and the engine's electric cooling fan in response to requests from
the Automatic Temperature Control (ATC) ECU.
A/C request
When the ATC ECU supplies the ECM with an A/C request, the ECM energises the compressor clutch relay. The
compressor clutch relay is located in the engine compartment fuse box. It is a four pin normally open relay. This means
that the relay must be energised to drive the compressor clutch. During periods of high driver demand such as hard
acceleration or maximum rev/min the ECM will disable the compressor clutch for a short time. This is to reduce the
load on the engine.
The operation of the A/C request is via a switch being connected to earth. Voltage is supplied via pin 9 of connector
C0658 of the ECM, at the point at which the switch is pressed the connection to the earth path is made and the
compressor clutch is engaged.
The ECM provides the earth for the relay windings to allow the compressor clutch relay contacts to close and the
compressor 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 windings. When the ECM closes down the earth path, the return spring in the relay will
pull the contacts apart to shut down the compressor clutch drive. Fuse 6, located in the engine compartment fuse box,
provides voltage to the compressor clutch relay switching contacts. The relay windings are supplied with battery
voltage from the main relay, also located in the engine compartment fuse box. The earth path for the relay windings
is via pin 29 of the ECM connector C0658. When the relay is energised the output from the switching contacts is
directly to the compressor clutch.
Cooling fan request
The A/C fan request is an input to the ECM from the ATC ECU to request that the engine's electric cooling fan is
activated to provide additional cooling for the A/C condenser.
The cooling fan relay is located in the engine compartment fuse box and is also controlled by the ECM. It is a four pin
normally open relay. This means that the relay must be energised to drive the cooling fan. The cooling fan is used
especially when the engine is operating at excessively high temperatures. It is also used as a part of the ECM backup
strategy if the ECT sensor fails.
The operation of the cooling fan request is via a switch being connected to earth. Voltage is supplied via pin 23 of
connector C0658 of the ECM, at the point at when the switch is pressed the connection to the earth path is made and
the cooling fan is engaged.
The ECM provides the earth for the cooling fan relay windings to allow the relay contacts to close and the cooling fan
motor to receive battery voltage. The ECM uses a transistor as a switch to generate an open circuit in the earth path
of the relay windings. When the ECM closes down the earth path, the return spring in the relay will pull the contacts
apart to shut down the cooling fan motor drive. Input to the A/C cooling fan relay switching contacts is via fuse 4
located in the engine compartment fuse box. The relay windings are supplied with battery voltage from the main relay,
also located in the engine compartment fuse box. The earth path for the relay windings is via pin 4 of the ECM
connector C0658. When the relay is energised the output from the switching contacts is directly to the cooling fan
motor.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-47
REPAIRS
Engine control module (ECM)
$% 18.30.03
All replacement ECM's are configured for two track
TP sensors. When fitting replacement ECM to
vehicle with three track TP sensor, TestBook must be
used to configure ECM for three track TP sensor.
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Release retaining strap and remove vehicle
jack.
4.Remove screw, release ECM and disconnect 2
multiplugs.
5.Remove ECM.
Refit
1.Position new ECM and connect multiplugs.
2.Fit ECM and tighten screw.
3.Fit vehicle jack and secure retaining strap.
4.Connect battery earth lead.
5.Fit battery cover and secure with fixings.
6.Programme ECM using TestBook.
Sensor - engine coolant temperature
(ECT)
$% 18.30.10
Remove
1.Remove fixings and remove engine acoustic
cover.
2.Release fixings and remove cooling fan cowl.
3.Disconnect multiplug from ECT sensor.
4.Remove sensor from coolant outlet elbow and
discard sealing washer.
Refit
1.Clean ECT sensor and coolant outlet elbow
mating faces.
2.Fit new sealing washer to ECT sensor. Fit
sensor and tighten to 15 Nm (11 lbf.ft). Connect
multiplug.
3.Fit cooling fan cowl and secure with fixings.
4.Fit engine acoustic cover and secure with
fixings.
5.Top up cooling system.

+ MAINTENANCE, PROCEDURES,
Cooling system.

ENGINE MANAGEMENT SYSTEM - TD5
18-1-48 REPAIRS
Sensor - crankshaft (CKP)
$% 18.30.12
Remove
1.Disconnect multiplug from CKP sensor.
2.Remove bolt securing CKP sensor. Remove
CKP sensor from gearbox housing and discard
'O' ring.
3. If fitted:Remove and discard spacer.
Refit
1.Clean gearbox housing and CKP sensor.
2. If fitted:Fit new spacer.
3.Fit new 'O' ring, position CKP sensor to
gearbox housing and tighten bolt to 9 Nm (7
lbf.ft).
4.Connect multiplug to CKP sensor.
Air filter assembly
$% 19.10.01
Remove
1.Release turnbuckles and remove battery
cover.
2.Disconnect battery earth lead.
3.Remove 2 nuts and remove air intake duct.
4.Release 2 clips securing MAF sensor.
5.Release MAF sensor from air filter cover and
position aside.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-49
6.Release air filter from 3 grommets, remove
assembly and discard 'O' ring.
7.Remove 2 screws, remove AAP sensor and
discard 'O' ring.
Refit
1.Clean MAF sensor and air filter mating faces.
2.Fit new 'O' ring to air filter.
3.Clean AAP sensor.
4.Using new 'O' ring, fit AAP sensor and tighten
screws.
5.Position air filter assembly and secure in
grommets.
6.Position MAF sensor and secure clips.
7.Position intake duct to air filter and tighten nuts.
8.Connect battery earth lead.
9.Fit battery cover and secure with fixings.
Element - air filter
$% 19.10.10
Remove
1.Release 2 clips and disconnect MAF sensor
from air filter cover.

ENGINE MANAGEMENT SYSTEM - TD5
18-1-50 REPAIRS
2.Disconnect multiplug from AAP sensor.
3.Release 2 clips and remove cover from air
filter.
4.Remove air filter element.
Refit
1.Clean air filter body and cover.
2.Fit new air filter element.
3.Position air cleaner cover and secure clips.
4.Position MAF sensor and secure clips.
5.Connect multiplug to AAP sensor.
Sensor - fuel temperature
$% 19.22.08
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Release fixings and remove battery cover.
3.Disconnect battery earth lead.
4.Disconnect multiplug from fuel temperature
sensor.
5. Thoroughly clean area around fuel
temperature sensor before removal.
6.Remove fuel temperature sensor and discard
sealing washer.
Refit
1.Clean fuel temperature sensor mating faces.
2.Fit new sealing washer and tighten fuel
temperature sensor to 13 Nm (10 lbf.ft) .
3.Connect multiplug to fuel temperature sensor.
4.Connect battery earth lead.
5.Fit battery cover and secure fixings.
6.Fit engine acoustic cover, and secure with
fixings.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-53
Element - fuel filter
$% 19.25.07
Remove
1.Release turnbuckles and remove battery cover.
2.Disconnect battery earth lead.
3.Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
4.Clean area around fuel filter.
5.Disconnect multiplug from filter element.
6.Remove fuel filter element.
Refit
1.Clean fuel filter and mating face.
2.Fit new fuel filter element and connect
multiplug.
3.Remove stand(s) and lower vehicle.
4.Connect battery earth lead.
5.Fit battery cover and secure the fixings.
Cooler - fuel
$% 19.25.30
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Remove battery cover.
3.Disconnect battery earth lead.
4.Drain cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
5.Release 3 clips and disconnect 3 coolant hoses
from fuel cooler.
6.Release 2 fuel hoses from fuel cooler.
CAUTION: Always fit plugs to open
connections to prevent contamination.
7.Release vacuum pipe clip from fuel cooler.
8.Noting which bolts are removed from the upper
fixing holes, remove 4 bolts securing fuel cooler
to inlet manifold. Remove cooler.
Refit
1.Clean fuel hose connections.
2.Apply Loctite 242 to the two upper bolts.
3.Position fuel cooler to inlet manifold, fit bolts
and tighten the upper bolts to 18 Nm (13 lbf.ft)
and the lower bolts to 25 Nm (18 lbf.ft).
4.Connect fuel hoses to fuel cooler.
5.Connect coolant hoses to fuel cooler, secure
with clips.
6.Secure vacuum hose to fuel cooler.
7.Refill cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
8.Fit engine acoustic cover and secure with
fixings.
9.Connect battery earth lead.
10.Fit battery cover.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-55
Turbocharger
$% 19.42.01
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Release fixings and remove battery cover.
3.Disconnect battery earth lead.
4.Remove cooling fan cover.
5.Remove 3 bolts and remove exhaust manifold
heat shield.
6.Release clip and disconnect breather hose
from camshaft cover.
7.Release clip and disconnect vacuum hose from
turbocharger wastegate.
8.Loosen clips and release air intake and outlet
hoses from turbocharger. 9.Remove turbocharger oil feed banjo bolt and
discard sealing washers.
10.Remove 2 bolts and release turbocharger oil
drain pipe and discard gasket.
11.Remove 3 nuts and release exhaust front pipe
from turbocharger and discard gasket.
12.Remove 3 nuts securing turbocharger to
exhaust manifold.
13. Remove turbocharger and discard gasket.
Refit
1.Clean turbocharger and exhaust manifold
mating faces.
2.Using a new gasket, fit turbocharger to exhaust
manifold and tighten nuts to 30 Nm (22 lbf.ft).
3.Using new gasket, align exhaust front pipe and
tighten nuts to 30 Nm (22 lbf.ft).
4.Using new gasket, align turbocharger drain
pipe and tighten bolts to 9 Nm (7 lbf.ft).
5.Fit banjo bolt to oil feed pipe using new sealing
washers and tighten to 25 Nm (18 lbf.ft)..
6.Position air hoses to turbocharger and tighten
clips.
7.Position and secure breather hose to camshaft
cover.
8.Position and secure vacuum hose to
turbocharger wastegate.
9.Position exhaust manifold heat shield and
tighten M6 bolts to 9 Nm (7 lbf.ft) and M8 bolt to
25 Nm (18 lbf.ft).
10.Fit fan cowl and secure fixings.
11.Fit acoustic cover and secure the fixings.
12.Connect battery earth lead.
13.Fit battery cover and secure fixings.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-59
Regulator - fuel pressure
$% 19.45.06
Remove
1.Release turnbuckles and remove battery cover
2.Disconnect battery earth lead.
3.Remove 3 bolts and remove engine acoustic
cover.
4.Remove 2 bolts and remove engine lifting eye.
5.Position cloth to absorb fuel spillage.
6.Release and disconnect hose from fuel cooler. 7.Release and disconnect fuel hose from
pressure regulator.
Always fit plugs to open connections to
prevent contamination.
8.Disconnect multiplug from fuel temperature
sensor.
9.Remove 3 bolts, remove pressure regulator
from cylinder head and collect gasket.
10.Remove and discard 'O' ring and fuel filter.