Four-Wheel Drive Systems: Description And Operation
The transfer box control module uses Diagnostic Trouble Codes (DTC), which relate to transfer box electrical faults.
Clutch and Range Change Mechanism Calibration
In order for the range change mechanism to function correctly, the transfer box control module must be calibrated to the
mechanical dimensions of the transfer box that it is connected to.
This procedure will need to be followed if one of the following occurs:
The vehicle is first assembled
The switch is changed
The transfer box control module is changed
The transfer box or range position sensor is changed
Vehicle or transfer box control module fault has caused the transfer box to revert to an undefined range.
Calibration can be carried out using the service tool or by following this procedure:
Switch ignition to position II without the engine running
Select automatic or manual transmission neutral
Depress the throttle pedal fully
Press and hold the range change switch for 5 or more seconds to allow calibration to start
When the calibration is heard to start, the switch and throttle pedal can be released
Upon adopting high range, start the engine and wait 30 seconds while the first calibration of the clutch in high
range is done. While this calibration process is in progress, no shifting is accepted
Switch ignition off and wait 15 seconds
Start engine
Perform a range change to low range. Wait 30 seconds while the first calibration of the clutch in low range is done.
While this calibration process is in progress, no shifting is accepted
Switch ignition off and wait 15 seconds
Range and clutch calibration is now complete.
Manual Transmission Gear Learning Process
The transfer box control module must learn the characteristics of the manual transmission to which it is connected to be
able to correctly recognise which gear the driver has selected.
This procedure will need to be followed if one of the following occurs:
The vehicle is first assembled
The switch is changed
The transfer box control module is changed
The manual transmission or gear position sensor is changed.
The manual transmission calibration procedure can be carried out in low or high range according to the following process:
Start the engine
Drive the vehicle in reverse steadily for approximately 5 seconds
Drive the vehicle forwards in all gears steadily, spending a minimum of 5 seconds in each gear When driving in
each gear it is important that the clutch is fully released after a gear change so that there is no clutch slipping
during the learning phase. The transfer box control module checks clutch position during learning and will not
learn if the clutch is not fully released in each gear. This is particularly relevant for reverse gear where it is natural
for drivers to slip the clutch.
When driving in each gear it is important that the clutch is fully released after a gear change so that there
is no clutch slipping during the learning phase. The transfer box control module checks clutch position
during learning and will not learn if the clutch is not fully released in each gear. This is particularly relevant
for reverse gear where it is natural for drivers to slip the clutch.
Key off for 15 seconds to save learning
To check that the learning is completed key back on and select a gear. The gear should be recognised without the
vehicle moving. T4 also shows if the transmission learning has been completed.
SYSTEM OPERATION
