When replacing a control unit it is necessary to variant code it correct. The variant code can be read from the old control unit as a datalist parameter "Controller, variant coding". Valid variant code can also be found in workshop manual or similar.
Note:
A faulty variant coding can reduce the car safety and/or performance.
A workshop manual or the variant code from old control unit must be available.
The control unit version must be correct to accept variant coding.
Some control units can not be coded.
Test prerequisites:
A valid variant code for control unit.
The battery voltage should be above 12V
Ignition on, engine off.
All the electrical loads should be switched off.
Procedure:
If possible, read the variant code from the old control unit.
Start the function "Code control unit".
Enter the variant code in the presented input field, confirm with 'OK'.
A dialog box will confirm if variant coding was successful or not.
If the variant coding fails, check that the variant code is valid.
Exit function.
Turn the ignition "Off" and wait 60 seconds. Turn the ignition "On". Re-establish contact with system and check variant coding.