VOLVO
ECM-C104 - Communication between control modules. Signal missing
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)
Show models by year and engine (6)
- Volvo C30 (2007–2013)2007–2010Engine D4204T only
- Volvo C70 (2006–2013)2008–2010Engine D4204T only
- Volvo S40 (2004–2013)2004–2006Engine D4204T, D4204T2 only
- Volvo S40 (2004–2013)2007–2010Engine D4204T only
- Volvo V50 (2004–2013)2004–2006Engine D4204T, D4204T2 only
- Volvo V50 (2004–2013)2007–2010Engine D4204T only
What does this fault code mean?
The engine control module watches the CAN links to the CEM and to the steering wheel module (SWM). The fault code is set when the engine control module finds that the link to either of them is not working.
Possible causes
- Poor contact or oxidation in a connector, or loose connections
- Open circuit in one of the CAN wires
- Short circuit between the CAN wires
- Internal fault in the engine control module
- Internal fault in some other 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. There is no specific fault-tracing procedure for this code
- 2Check that the fuses are intact and that the battery is connected
- 3Check the connectors at the engine control module, the CEM and the steering wheel module for play and corrosion
- 4Look for chafing and breaks on the CAN wires between the control modules
- 5Erase the fault code only after the other faults are fixed, then road test the car to see whether the fault returns
- 6If the fault remains, have a workshop check the communication with diagnostic equipment
Symptoms you may notice2
- A text message and warning symbol appear in the display
- The Check engine warning lamp lights up or behaves abnormally
General guidance for car owners. Diagnosis on the car can point to a different cause.