VOLVO
TCM-DF13 - Control module communication. Control module communication
System
Transmission Control Module (TCM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS40 (1996–2004), V40 (1996–2004)
Show models by year and engine (2)
What does this fault code mean?
The transmission control module (TCM) and the engine control module exchange information over the CAN network, which has two signal wires, CAN H and CAN L. The code is set when the transmission control module detects that the CAN wires are shorted to supply voltage. It is one of several codes for faults on the same wires, and this one covers a short to positive.
Possible causes
- Short to supply voltage in the CAN wires
What you can do
- 1Read the code, clear it and road test the car to see whether it comes back
- 2With the ignition off, check the CAN wiring between the gearbox and the engine for chafing, damage and loose connectors
- 3Use a multimeter to check that the CAN wires are not shorted to positive
- 4Check the connectors at the transmission control module and the engine control module for contact resistance and oxidation
- 5Have a workshop check CAN communication with diagnostic equipment and replace a control module if the fault remains after the wiring has been checked
Symptoms you may notice1
- The automatic gearbox warning lamp flashes
General guidance for car owners. Diagnosis on the car can point to a different cause.