Replacing Control Unit For All-Wheel Drive Electronics
- Irreparable damage to control unit
- Damage to control unit
- Fault entries in the control unit
- Control unit programming/coding is aborted
- Malfunctions in the control unit, even during programming
- Switch off ignition before disconnecting the control unit.
- Make sure that the power supply is not interrupted during programming/coding.
- Connect the battery charger with at least > current 90 A to the vehicle battery.
Information
The PIWIS Tester instructions take precedence since the description may be different with later Tester releases.
The procedure described here has been structured in general terms. Different text or additional information may appear on the PIWIS Tester .
Connect the Tester to the vehicle and start it. Switch on ignition.
Place original remote control (hand-held transmitter) in emergency start tray.
Emergency start tray
Select the vehicle type if required.
Select the All-wheel control (PTM) control unit in the overview . Press F12 to continue.
The message "Create Vehicle Analysis Log (VAL)?" appears. Press F11 to continue.
Maintenance/repairs must now be selected.
Control unit replacement must now be selected. Press F12 to continue.
Information
If only the all-wheel drive electronics (PTM) control unit is replaced, select the "Control unit replacement" function.
If the All-wheel drive electronics (PTM) control unit and transfer box are replaced, the "Control units and transmission replacement (together)" function must be selected.
Read out data. Press F12 to continue.
The Tester displays the message: Control unit data read-out successful . Press F12 to continue.
If the data could not be read out, install a new control unit and continue with Step 12
Switch off ignition. Replace control unit for all-wheel control system.
> 399519 REMOVING AND INSTALLING CONTROL UNIT FOR ALL-WHEEL DRIVE ELECTRONICS
Switch on the ignition.
Switch on ignition. Select Write data in the menu (procedure described above). Press 12 to continue
Perform procedure according to menu guidance. Read and follow the information and instructions on the Tester.
The Tester displays the message: Data has been written.
If the data could be read out and written, continue with Step 16
Change oil in transfer gear.
> 399055 CHANGING OIL FOR TRANSFER GEAR
Drive links/checks must be selected.
Reset oil ageing learning values must now be selected. Press F12 to continue.
Reset learning values in accordance with menu guidance. Read and follow the instructions and information on the Tester.
Read out the fault memory . Clear it if necessary.
Exit the diagnostic application. Switch off ignition. Disconnect the Tester from the vehicle.