1999 LAND ROVER DISCOVERY ECO mode

ENGINE MANAGEMENT SYSTEM - V8
18-2-58 DESCRIPTION AND OPERATION
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
Function
The CAN system uses a twisted pair of wires to form the 'data bus' to minimise electrical interference. This method of
serial interface is very reliable and very fast. The information messages are structured so that each of the receivers
(ECM or EAT ECU) is able to interpret and react to the messages sent.
The CAN 'data bus' is directly connected between pin 36 of connector C0637 of the ECM and pin 16 of connector
C0193 at the EAT ECU, and pin 37 of connector C0637 of the ECM and pin 44 of connector C0193 at the EAT ECU.
The CAN system can fail in the following ways:
lCAN data bus wiring open circuit.
lCAN data bus wiring short circuit.
In the event of a CAN data bus failure any of the following symptoms may be observed:
lMIL illuminated after 2 drive cycles (NAS only).
lEAT defaults to 3rd gear only.
lHarsh gearshifts.
l'Sport' and 'manual' lights flash alternately.
Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by
TestBook.
Drive cycles
The following are the TestBook drive cycles:
⇒ Drive cycle A:
1Switch on the ignition for 30 seconds.
2Ensure engine coolant temperature is less than 60°C (140°F).
3Start the engine and allow to idle for 2 minutes.
4Connect TestBook and check for fault codes.
⇒ Drive cycle B:
1Switch ignition on for 30 seconds.
2Ensure engine coolant temperature is less than 60°C (140°F).
3Start the engine and allow to idle for 2 minutes.
4Perform 2 light accelerations (0 to 35 mph (0 to 60 km/h) with light pedal pressure).
5Perform 2 medium accelerations (0 to 45 mph (0 to 70 km/h) with moderate pedal pressure).
6Perform 2 hard accelerations (0 to 55 mph (0 to 90 km/h) with heavy pedal pressure).
7Allow engine to idle for 2 minutes.
8Connect TestBook and with the engine still running, check for fault codes.
P Code J2012 Description Land Rover Description
P0600 Serial communication link malfunction CAN time out
P1776 Transmission control system torque interface
malfunctionEAT torque interface error

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-59
⇒ Drive cycle C:
1Switch ignition on for 30 seconds.
2Ensure engine coolant temperature is less than 60°C (140°F).
3Start the engine and allow to idle for 2 minutes.
4Perform 2 light accelerations (0 to 35 mph (0 to 60 km/h) with light pedal pressure).
5Perform 2 medium accelerations (0 to 45 mph (0 to 70 km/h) with moderate pedal pressure).
6Perform 2 hard accelerations (0 to 55 mph (0 to 90 km/h) with heavy pedal pressure).
7Cruise at 60 mph (100 km/h) for 8 minutes.
8Cruise at 50 mph (80 km/h) for 3 minutes.
9Allow engine to idle for 3 minutes.
10Connect TestBook and with the engine still running, check for fault codes.
NOTE: The following areas have an associated readiness test which must be flagged as complete, before a problem
resolution can be verified:
lcatalytic converter fault;
lEvaporative loss system fault;
lHO
2 sensor fault;
lHO
2 sensor heater fault.
When carrying out a drive cycle C to determine a fault in any of the above areas, select the readiness test icon to
verify that the test has been flagged as complete.
⇒ Drive cycle D:
1Switch ignition on for 30 seconds.
2Ensure engine coolant temperature is less than 35°C (95°F).
3Start the engine and allow to idle for 2 minutes.
4Perform 2 light accelerations (0 to 35 mph (0 to 60 km/h) with light pedal pressure).
5Perform 2 medium accelerations (0 to 45 mph (0 to 70 km/h) with moderate pedal pressure).
6Perform 2 hard accelerations (0 to 55 mph (0 to 90 km/h) with heavy pedal pressure).
7Cruise at 60 mph (100 km/h) for 5 minutes.
8Cruise at 50 mph (80 km/h) for 5 minutes.
9Cruise at 35 mph (60 km/h) for 5 minutes.
10Allow engine to idle for 2 minutes.
11Connect TestBook and check for fault codes.
⇒ Drive cycle E:
1Ensure fuel tank is at least a quarter full.
2Carry out Drive Cycle A.
3Switch off ignition.
4Leave vehicle undisturbed for 20 minutes.
5Switch on ignition.
6Connect TestBook and check for fault codes.

ENGINE MANAGEMENT SYSTEM - V8
18-2-72 DESCRIPTION AND OPERATION
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.

TRANSFER BOX - LT230SE
DESCRIPTION AND OPERATION 41-15
Functionality – Vehicles up to 03 model year only
The function of the differential lock used in previous applications is performed on this vehicle by the Electronic Traction
Control System. However, for the purposes of 2 wheel rolling road testing , the differential lock components are
retained. For all driving conditions however, the differential lock must be set in the unlocked position.
Up to 03 model year specification shown
The differential lock must only be engaged for 2 wheel rolling road testing as engagement of the lock disables the
traction control feature and inhibits correct operation of the electronic brake distribution and hill descent features. 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. The lock may be engaged/disengaged by using a 10 mm open ended spanner
on the flats (arrowed) machined on the differential lock selector shaft.
Vehicles not fitted with a differential lock may be identified by there being no cover or selector shaft (arrowed) 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.
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.
WARNING: VEHICLES NOT FITTED WITH A DIFFERENTIAL LOCK MUST NOT BE TESTED ON A ROLLING
ROAD WHERE THE ROLLERS ARE DRIVEN BY THE VEHICLE.

TRANSFER BOX - LT230SE
41-16 DESCRIPTION AND OPERATION
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 - Vehicles from 03 model year
Vehicles from 03 model year are fitted with two differential lock warning lamp switches.
Both switches are of a new design and are fitted into the top of the front output housing. The switches are connected
to the SLABS ECU and are 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
The differential lock warning lamp is amber coloured and is located in the instrument pack.
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.
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 up to 03 Model Year. 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.

TRANSFER BOX - LT230SE
DESCRIPTION AND OPERATION 41-17
High/Low range and differential lock selector lever assembly – Vehicles from 03 model year
1Selector lever
2High/Low range cable
3Differential lock cable4Interlock solenoid - North America and Japan
only
On vehicles 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.

TRANSFER BOX - LT230SE
OVERHAUL 41-45
4. 03 Model Year onwards: Using tools LRT-99-
003 and LRT-41-006, fit bearing tracks to
intermediate gears ensuring that tracks are fully
seated against shoulders in gears.
5.Using a micrometer, measure the width of each
bearing inner track. 6.Record each reading as measurement 'A' and
'B', both measurements should fall within the
range of 21.95 to 22.00 mm (0.864 to 0.866 in).
7.Fit inner bearing track 'A' onto tool LRT-41-017
and position intermediate gear cluster onto
bearing 'A'.
8.Fit inner bearing track 'B' to intermediate gear,
apply finger pressure to bearing inner track
and rotate intermediate gear 5 to 10 turns to
settle in bearing rollers.
9.Attach a DTI to base of tool LRT-41-017 , zero
gauge on top of tool post and take 2
measurements at 180° of the step height
between the top of the tool post and the
bearing inner track. Take an average of the two
readings and record this as measurement 'C'.
Measurement 'C' should be in the range of 0.15
to 0.64 mm (0.006 to 0.025 in).
10.Using the formula 103.554 mm (4.0769 in) -'A'-
'B'-'C', calculate the length of bearing spacer
required. From the result of the calculation
round DOWN to the nearest length of spacer
available to give a correct bearing pre-load of
0.005 mm (0.002 in). 40 spacers are
available ranging in length from 58.325 mm
(2.296 in) to 59.300 mm (2.335 in) rising in
increments of 0.025 mm (0.001 in).
11.Remove intermediate gear assembly from tool
LRT-41-017.
12.Lubricate and fit bearings and selected spacer
to intermediate gear.
13.Position tool LRT-41-004 through bearings
and spacer.

TRANSFER BOX - LT230SE
OVERHAUL 41-47
3.Note position of longest bolt and remove 8 bolts
securing front output shaft housing to main
casing and remove housing.
Note: Carry out the following operations if
differential lock is fitted.
4. Differential lock fitted: Remove 3 bolts
securing differential lock selector housing and
remove housing.
5. Differential lock fitted: Remove and discard
'O' rings from selector housing.
6. Up to 03 Model Year: Remove Allen plug and
remove differential lock detent spring and ball.
7. Up to 03 Model Year: Remove differential lock
warning lamp switch and locknut.
8. 03 Model Year onwards - differential lock
fitted: Remove 2 differential lock warning lamp
switches and sealing washers.9. 03 Model Year onwards - differential lock
fitted: Note position of longest bolt and remove
8 bolts securing front output housing to main
casing and remove housing.
10. 03 Model Year onwards - differential lock
fitted: Remove 3 bolts securing differential lock
selector housing and bracket, remove bracket
and housing.
11. 03 Model Year onwards - differential lock
fitted: Remove and discard 'O' rings from
selector housing.
12. 03 Model Year onwards - differential lock
fitted: Remove detent plug, recover spring and
ball.
13. All transfer boxes fitted with differential
lock: Compress differential lock selector fork
spring and remove retaining clips from each
end of spring.
14. All transfer boxes fitted with differential
lock: Withdraw differential lock selector shaft
from front output housing, recover spring and
remove selector fork.