2002 LAND ROVER DISCOVERY ECO mode

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-65
When cruise is requested, the cruise control ECU provides voltage to the vacuum pump assembly and provides a
pulsed earth signal. The pulse period is dependent on the difference between the vehicle set speed and the actual
road speed. Removing the earth path switches off the pump.
Several fault codes can be generated:
Fault codes
1"Output power LOW when HIGH is expected" is flagged when Pin C0239-11 is shorted to earth.
This could be due to an external fault or an internal ECU fault and will be set if pin C0239-11 is LOW for longer
than 240 milliseconds, while in cruise mode.
2"Output power HIGH when LOW is expected" is flagged when Pin C0239-11 is shorted to battery voltage.
This could be due to an external fault or internal ECU fault and will be set if pin C0239-11 is HIGH for longer than
250 milliseconds while not in cruise mode.
3"Output pump LOW, when High is expected" is flagged when Pin C0239-7 is shorted to earth.
This could be due to an external fault or an internal ECU fault. This fault will be set if pin C0239-11 is HIGH for
longer than 7.5 milliseconds while pin C0239-7 is LOW for longer than 2.5 milliseconds while decelerating under
control of cruise.
4"Output pump HIGH, when LOW is expected" is flagged when Pin C0239-7 is shorted to battery voltage.
This could be due to an external fault or an internal ECU fault. This fault will be set if pin C0239-7 is LOW for
longer than 7.5 milliseconds of the last 8 pulses when the pump is switched on while accelerating under the
control of cruise.
5Output valve LOW, when HIGH is expected is flagged when Pin C0239-7 is shorted to battery voltage.
This could be due to an external fault or an internal ECU fault and will be set if pin C0239-17 is LOW for longer
than 2.5 milliseconds while pin C0239-7 is HIGH for longer than 2.5 milliseconds and pin C0239-11 is also HIGH
for longer than 7.5 milliseconds, while decelerating under control of the cruise control ECU.
6Output valve HIGH, when LOW is expected is flagged when Pin C0239-17 is shorted to battery voltage.
This could be an external fault or an internal ECU fault. The fault will be set if pin C0239-17 remains HIGH for
longer than 35 milliseconds after the vacuum control valve is switched on, while accelerating under control of
the cruise control ECU.
TestBook can be used to determine the fault codes present as well as the general status of the system.
Pneumatic actuator
The cruise control ECU controls the position of the throttle disc by regulating the amount of vacuum applied by the
vacuum pump to the pneumatic actuator. The pneumatic actuator is an air tight bellow coupled to the pneumatic pump
via a vacuum pipe. The pump evacuates the air inside the bellow and pipe, which collapses the bellow. This pulls on
a cable, which moves the throttle disc to the desired position. On vehicles from 03 model year, the cruise control
vacuum pump and pneumatic actuator assembly is fitted with a heat shield to protect the components from heat from
the exhaust manifold.

ENGINE MANAGEMENT SYSTEM - V8
18-2-72 REPAIRS
5.Noting their fitted position disconnect ht leads
from ignition coil.
6.Remove 3 screws securing ignition coil to
support bracket and remove coils.
Refit
1.Position ignition coil to support bracket, fit and
tighten screws.
2.Connect ht leads to ignition coil ensuring they
are in the correct position.
3.Carefully position ignition coil assembly
between engine and bulkhead.
4.Connect ht leads to spark plugs and secure ht
leads to rocker covers.
5.Connect multiplugs to ignition coils.
6.Fit upper inlet manifold assembly.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Gasket - inlet
manifold - upper - Without Secondary Air
Injection.
Engine control module (ECM)
$% 18.30.01
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Remove fixings securing fascia RH closing
panel, release diagnostic socket RH drive
models, and remove panel.
4.Remove 2 fixings and remove 'A' post lower
trim.

FUEL DELIVERY SYSTEM - TD5
DESCRIPTION AND OPERATION 19-1-7
The fuel pressure regulator is located in a cast alloy housing which is attached to the rear right hand corner of the
cylinder head with three flanged bolts and sealed with a metal gasket. On pre EU3 models there are two ports in the
housing that connect with ports in the cylinder head for fuel pressure feed and return. On EU3 models there is a port
in the housing that connects with a port in the cylinder head for fuel pressure feed and a single external port for fuel
return. A gauze filter is located in the pressure feed port in the cylinder head and filters the fuel before it reaches the
injectors. The filter is a fit for life item but can be changed if required. An 'O' ring is located in a recess in the cylinder
head and provides additional sealing for the pressure feed port between the gauze filter, the cylinder head and the
housing.
A union and pipe is attached to the feed port in the housing and connects with a quick release coupling to the fuel
pressure feed pipe from the fuel pump. A second union and hose is located in the return port and provides the fuel
return connection to the fuel cooler. A third port provides location for the fuel temperature sensor which is sealed to
the housing with a bonded seal. The fuel temperature sensor is used by the Engine Control Module (ECM) for engine
management.
The fuel pressure regulator is located in a machined port in the lower part of the housing. The regulator is sealed in
the housing with two 'O' rings and secured with an internal circlip.
The regulator maintains the fuel pump delivery pressure at 4 bar (58 lbf.in
2). When the fuel pressure exceeds 4 bar
(58 lbf.in2), the regulator opens and allows fuel to return to the fuel tank via the fuel cooler. The fuel returned from the
regulator is directed back into the fuel filter before being drawn by the high pressure stage of the fuel pump and
directed back to the injectors. A special tool can be attached to the regulator housing fuel feed port and allows for the
fitment of a suitable gauge to measure fuel pump delivery pressure.
Injectors
1Solenoid housing
2Electrical connector
3Push rod socket
4Push rod return spring
5Housing
6Fuel delivery port7Fuel return port
8Nozzle cap nut
9Copper washer
10Nozzle
11'O' ring
12Cap screw 2 off

TRANSFER BOX - LT230SE
DESCRIPTION AND OPERATION 41-13
Description
General
The LT 230SE transfer box is mounted at the rear of the gearbox and transmits drive via high or low reduction ratios
to the front and rear axles via the propeller shafts. The high/low ratios are 1.211:1 and 3.32:1 respectively.
Transfer boxes fitted to this model have the prefixes 41D and 42D to the unit serial number. Prefix 41D denotes that
the unit is not fitted with interlock whilst 42D denotes that interlock is fitted.
Vehicles up to 03 model year – Whilst similar to LT230Q transfer boxes fitted to other models, the LT230SE transfer
box has certain engineering modifications incorporated which are as follows:
lUprated torque capacity
lModified front and rear output and cross shaft housings
lIntermediate gear bearing pre-load now controlled by a selective, non-collapsible spacer
lSpeedometer drive and driven gears not fitted for this application
lModified high/low sleeve
lModified front output flange and mud shield
lDifferential lock fitted to certain vehicles, but no longer driver operated
lFixed setting of differential lock warning lamp switch on vehicles fitted with differential lock
Vehicles from 03 model year – The LT230SE transfer box is as described above for vehicles up to 03 model year
with the following modifications:
The following items are introduced on vehicles from 03 model year
lRibs added to main casing to reduce operating noise
lBearing retaining nut on the differential carrier has patchlock added to the threads
lInterlock solenoid moved from main casing to selector lever assembly
lIntermediate gears modified with machined internal shoulder and bearing circlips deleted
The following items are introduced later in the 03 model year build programme and therefore may not appear on all
03 model year vehicles
lDriver operated differential lock (if fitted)
lHigh/Low selector shaft fitted with spring assist
lExisting differential lock switch replaced by new design switch.
lNew secondary differential lock switch installed in the front output housing
Construction
The transfer box comprises three main assemblies; the main casing, the front output housing and the rear output
housing. Both output housings and all cover plates are sealed to the main casing by sealant; mud and water ingress
being prevented by mud shields located on the output flanges.
Main casing
The main casing carries the mainshaft input gear, the intermediate gears and the differential, together with the high/
low range gears, selector shaft and fork. The front and rear output housings are bolted to either side of the main
casing.
Transmission neutral sensor
A transmission neutral sensor is fitted on automatic gearbox vehicles for North America and Japan. The sensor is
connected to the BCU and is normally in the open position. The sensor provides an earth path for the BCU which then
interprets the signal and activates an audible warning generated by the IDM if neutral is selected on the transfer box
when the ignition is on.

TRANSFER BOX - LT230SE
41-16 DESCRIPTION AND OPERATION
Functionality – Vehicles from 03 model year only
The differential lock must be engaged for 2 wheel rolling road testing. It will also be necessary to disconnect the
propeller shaft from the transfer box output shaft driving the axle whose wheels are NOT on the rolling road. In
addition, the ETC system must be deactivated by either, removing a fuse (10A fuse 28 in the passenger compartment
fusebox, labelled ABS) or disconnecting the ABS modulator pump. This must be done with the ignition switched off.
Note that the SLABS ECU may record a system fault.
The lock can be engaged or disengaged using the selector lever. Vehicles not fitted with a differential lock can be
identified by a high/low range selector lever with no differential lock functionality and the cover and selector shaft
(arrowed), not visible on the front output housing.
WARNING: VEHICLES NOT FITTED WITH A DIFFERENTIAL LOCK MUST NOT BE TESTED ON A ROLLING
ROAD WHERE THE ROLLERS ARE DRIVEN BY THE VEHICLE.
Differential lock warning lamp switch - if fitted - Vehicles up to 03 model year
A differential lock warning lamp switch connected to the SLABS ECU and operated by movement of the selector fork
and shaft is screwed into the top of the output housing. The switch connects to earth when the differential lock is
engaged.
Differential lock warning lamp switches - if fitted - Vehicles from 03 model year
Vehicles from 03 model year are fitted with two differential lock warning lamp switches.
One switch is of a new design and is fitted into the top of the front output housing in the same position as on previous
models. The switch is connected to the SLABS ECU and is operated by movement of the selector fork and shaft.
The second switch is located in a threaded hole on the forward face of the front output housing. The switch is also
connected to the SLABS ECU and is operated by movement of the selector shaft.
Both switches have an aluminium washer which seals the switch to the casing and also sets the switch position,
removing the requirement for a setting procedure.
Both switches are connected in parallel to earth when the differential lock is engaged. This earth is sensed by the
SLABS ECU which illuminates the differential lock warning lamp in the instrument pack.
Differential lock warning lamp - Vehicles up to 03 model year – if fitted
The differential lock warning lamp is located in the instrument pack and provides a warning to the driver when the
ignition is switched on that the differential lock is engaged. The warning lamp illuminates in a Red colour.
With the lock engaged, the traction control and electronic brake distribution warning lamps will also be illuminated.
Disengagement of the differential lock should be carried out with the ignition switched off. The warning lamps must
be extinguished when the ignition is switched on again.
Differential lock warning lamp – vehicles from 03 model year – if fitted
The differential lock warning lamp is located in the instrument pack and provides a visual warning to the driver, when
the ignition is on, the differential lock is engaged. The warning lamp illuminates in an amber colour.
When the lock is engaged, the warning lamp is illuminated and the instrument pack sounder emits three audible
chimes. When the lock is disengaged, the warning lamp is extinguished and the instrument pack sounder emits three
audible chimes.
Rear output housing
The rear output housing carries the output shaft and flange. A cable operated transmission brake is attached to the
housing, the brake drum being attached to the output flange.
The rear output shaft is supported in the housing by a single bearing and is splined into the differential rear sun gear.

TRANSFER BOX - LT230SE
DESCRIPTION AND OPERATION 41-17
Lubrication
Lubrication is by splash, oil filler/level and drain plugs being located in the main casing.
Internal pressures caused by thermal expansion and contraction are avoided by the use of a plastic breather pipe
venting the interior of the box to atmosphere. The pipe is attached to the top of the high/low selector housing by a
banjo bolt and is then routed in a continuously rising path into the engine compartment where the open end is secured
by a clip attached to the engine cylinder block.
Oil temperature warning lamp switch
An oil temperature switch is fitted to V8 engine models. In the event of the transfer box oil approaching maximum
recommended working temperature of 145
°C (293°F), the switch will close and a warning lamp in the instrument pack
will be illuminated.
High/Low range and differential lock selector lever assembly – Vehicles from 03 model year
1Selector lever
2High/Low range cable
3Differential lock cable
4Interlock solenoid

TRANSFER BOX - LT230SE
41-18 DESCRIPTION AND OPERATION
On vehicle fitted with a differential lock, the high/low range selector lever as fitted on previous models also
incorporates the differential lock selector on vehicles from 03 model year.
The lever can be moved forwards or backwards to select high, neutral or low range or sideways to select differential
lock engaged or disengaged, on vehicles with differential lock fitted.
The selector lever assembly comprises an aluminium casting with bosses for location of the two cables, the selector
lever mechanism and a housing for the interlock solenoid (if fitted). The upper face of the casting has threaded holes
which allow for the attachment of the casting to the mounting plate which is attached to the transmission tunnel.
A boss at the front provides location for the differential lock cable. The cable is attached to a lever which in turn is
attached to the selector lever. Movement of the selector lever is passed via the lever to the cable which moves the
differential lock selector shaft.
A second boss provides for the location of the high/low range cable. The cable is attached to a plate which moves in
a forward or rearward direction with the selector lever. On North American and Japanese specification models, plate
movement is prevented by an interlock solenoid when the ignition key is not in the ignition.
When fitted, the interlock solenoid is located on the right hand side of the selector lever casting. The solenoid is fitted
into a cast housing in the casting and retained with a circlip. Sealant is applied over the circlip to seal the solenoid in
the housing to prevent the ingress of dirt and moisture. The solenoid performs the same function as on previous
models, preventing the selection of neutral on the transfer box when the ignition key is not in the ignition.
A setting procedure is required for both the differential lock cable and the high/low range cable.

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-5
1Release button
2Mode switch
3Electrical connector
4Interlock solenoid (where fitted)
5Base6Gasket
7Securing bolt
8Lever
9Cover
10Position indicators
The selector lever assembly consists of a lever and a cover attached to a base. The base is located on a gasket and
secured to the transmission tunnel. The lever is hinged to the base. A latch in the lever engages with detents in the
base to provide the lever positions P, R, N, D, 3, 2, 1. The latch is disengaged by pressing a release button on the
lever knob. Except for lever movement between positions D and 3, the button must be pressed before the lever can
be moved. In some markets, vehicles incorporate an interlock solenoid at the bottom of the lever, which prevents the
lever being moved from P unless the ignition switch is in position II and the foot brake is applied. If the battery
becomes flat, the interlock system will prevent selector lever movement and removal of the ignition key.
The cover incorporates lever position indicators and the mode switch. The lever position indicators illuminate to show
the position of the selector lever. Illumination is controlled by the Body Control Unit (BCU). The mode switch is a non-
latching hinged switch that, when pressed, connects an earth to the EAT ECU to request a change of mode.
An electrical connector at the rear of the cover connects the selector lever assembly to the vehicle wiring.
Selector cable
The selector cable is a Bowden type cable that connects the selector lever assembly to a selector lever on the
gearbox. 'C' clips secure the ends of the outer cable to brackets on the selector lever assembly and the selector lever.
The inner cable is adjustable at the connection of the inner cable with the gearbox selector lever.