VOLVO
ECM-C103 - Communication, Transmission Control Module (TCM)
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The engine control module has registered a communication fault with the transmission control module (TCM), and the fault code is stored in the engine control module. Fault-tracing starts in the transmission control module, because the cause is most often there or in the CAN wiring between them.
Possible causes
- The cause lies in the transmission control module (TCM)
- Open circuit in one of the CAN wires
- Short circuit between the CAN wires
- Internal fault in the engine control module
- Internal fault in another control module on the same section of the CAN network
What you can do
- 1Start by reading the fault codes from the CEM and the other control modules, and fix them before erasing anything
- 2Check that the battery is charged and that the fuses are intact
- 3Check the connectors at the engine control module and the transmission control module for corrosion and loose contacts
- 4Look for chafing or pinched sections along the CAN wires between the control modules
- 5Erase this fault code only after the other fault codes are fixed, then road test the car to see whether the fault returns
- 6If the fault remains, have a workshop check the transmission control module and the CAN network with diagnostic equipment
Symptoms you may notice2
- Harsh gear changes
- The emissions warning lamp is lit
General guidance for car owners. Diagnosis on the car can point to a different cause.