LR3/Disco 3
maximum shift time of approximately one second is achieved.
If the control module is replaced, T4 must be connected to the vehicle and the transfer box control module self-calibration
procedure must be performed. This procedure must also be performed if the transfer box motor assembly is replaced.
Default/Limp-home Strategy
If a fault occurs with the transfer box, the transfer box control module or one of the required input signals i.e. road speed
signal, the control module records an error code and will respond appropriately to provide the highest level of system
capability under the specific fault conditions. The following fault states are possible:
If a driveline over temperature condition has occurred, after the driveline has been allowed to cool, clutch control will be
re-enabled and the warnings will disappear. There is no need to seek service assistance following an over temperature
event.
If clutch control or Range change is not possible due to a permanent fault the driver must seek service assistance at the
earliest opportunity.
If the system suffers a fault, which causes the transfer box to fail in neutral, the control module is designed to continue
attempting to engage the requested range or return to its original range for a fixed number of attempts. If this has not
been successful and the low range lamp is still flashing the driver should bring the vehicle to a halt and attempt the range
change again while stationary. If this does not work after a number of attempts, key off for 30 seconds, restart engine and
request range change again while stationary. The driver must seek service assistance at the earliest opportunity.
Transfer Box Control Module Pin Out Details
Connector C1319
Connector C1854
Fault state
System response
Driver warning
No reduction in capability
Diagnostic Trouble Code (DTC) will be
recorded but no effect on performance
Non
Clutch control not possible.
Temporary over temperature
condition
The tractive capability of the vehicle,
off road, is reduced.
Driveline over temperature warning lamp or
"Centre diff over temp reduce speed" on
message centre
Clutch control not possible.
Permanent fault
The tractive capability of the vehicle,
off road, is reduced.
Driveline fault warning lamp or "Centre diff fault
traction reduced" on message centre
Range change not possible
The system inhibits the driver from
making a range change
Driveline fault warning lamp or "Range change
inoperable" on message centre
Stuck in Transfer box neutral
The transfer box is stuck between
high and low range resulting in no
drive to wheels
Flash low range indicator plus "Park lock
failure apply hand/parkbrake" message on
message centre
Pin No.
Description
Input/output
1
Not used
-
2
Not used
-
3
CAN bus low
Data (input and output)
4
Range change selection switch - High
Input
5
Range change selection switch - Low
Input
6
CAN bus high
Data (input and output)
7
Key interlock solenoid
Output
8
LED-high
Output
9
LED-low
Output
