P1621

P1621

Diagnosis information - CAN

Communication, Tiptronic control unit

Diagnostic conditions
The Tiptronic control unit initially tests internal function sequences after wake-up. If they are OK, all diagnosable outputs are then tested and any faults are stored.
Tiptronic control unit wake-up through:

- Event-induced CAN message
- Ignition on

Possible fault causes
- No power supply for Tiptronic control unit
- Tiptronic control unit is incorrectly coded
- Short circuit or open circuit in the CAN drive
- Tiptronic control unit faulty (in most cases the cause is not the Tiptronic control unit but incorrect coding.)

Fault effects
- Communication via the CAN drive is no longer possible
- No other control units are able to communicate with the Tiptronic control unit

Affected contacts on the Tiptronic control unit
Connector [A]:
- 1 ground supply - terminal 31
- 2 ground supply - terminal 31
- 3 power supply - terminal 30
- 27 power supply - terminal 15
- 28 power supply - terminal 15
- 34 CAN drive low
- 46 CAN drive high