Semi-automatic transmission

U0101, U1200, U1202 

The diagnosis of the powertrain CAN communication between the TCM and the PCM is done by supervision of the received TCM powertrain CAN messages.

If a TCM powertrain CAN message is missing for a calibrated period of time, a timeout is detected and a signal fault CSSG is set.

If the checksum or the sequence number of a TCM powertrain CAN message is wrong for a calibrated period of time, a malfunction is detected and a plausibility fault CSSG is set.

If the content of a TCM powertrain CAN message during the following gear shift phases

no gear shift active

gear shift active with engine stop request

gear shift active without shifting

gear shift active with torque reduction phase

gear shift active with engine speed control phase

gear shift active with torque increase phase

is not rational, a malfunction is detected and a plausibility CSSG is set.