VOLVO
CEM-CFF0 - MMS Communication Faulty Signal
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The movement sensor for the alarm gives a signal that is short-circuited, either to voltage or to ground. This can make the battery discharge abnormally fast, and the control module logs the fault when the sensor signal is wrong. The fault can be checked by locking the car with the remote key.
Possible causes
- The signal is short-circuited to voltage or ground
What you can do
- 1Disconnect any battery charger, and close the doors, bonnet and tailgate before testing
- 2Lock the car with the remote key and see whether the fault code returns. If it does, the fault is still present
- 3Check the wiring to the movement sensor for chafing and that the connector is secure
- 4If no fault is found in the wiring, have a workshop replace the movement sensor
Symptoms you may notice4
- The alarm does not go off, with no visible or audible signal
- The battery is dead or has low voltage
- The engine does not start or does not turn over
- The engine is hard to start and cranks slowly
General guidance for car owners. Diagnosis on the car can point to a different cause.