VOLVO
CEM-DD1B - Communication with SCM control module. Signal missing
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?
When the alarm is armed, the central module checks the siren at regular intervals. If it gets no answer despite several attempts, the fault is logged, and the siren may then give a false alarm. The cause may be a break in the signal wire, a blown fuse or an internal fault in the siren.
Possible causes
- Open circuit in the signal wire to the siren
- Blown fuse
- Internal fault in the siren
What you can do
- 1Check the siren fuse in the fuse box, using the owner's manual
- 2Check that the siren gets power and that its earth point is clean and tight
- 3Follow the wire to the siren for breaks and chafing, and repair as needed
- 4If no fault is visible in the wiring, have a workshop replace the siren
Symptoms you may notice2
- False alarm
- The alarm does not go off, and no visible or audible signal comes
General guidance for car owners. Diagnosis on the car can point to a different cause.