VOLVO
CEM-B1D1783 - Battery Backed Sounder. Bus Signal / Message Failures. Value of signal protection calculation incorrect
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsV40 (2013–), V40 Cross Country (2013–)
Show models by year and engine (2)
What does this fault code mean?
The control module (CEM) exchanges messages with the alarm siren over the LIN bus, and the code is set when a message from the siren is incorrect. The fault can cause false alarms or stop the alarm from sounding, and poor contact in the connections is a common cause.
Possible causes
- Poor contact, oxidation or high resistance in the connections
- Damaged siren
What you can do
- 1Read and clear the code, then arm the alarm and see whether the fault returns
- 2Check that the connectors at the siren connections are fully seated and free from oxidation
- 3Look for loose or damaged connectors in the wiring harness to the siren
- 4Use a multimeter to check whether the wires to the siren touch ground or voltage with the ignition off
- 5If the fault remains, have a workshop with diagnostic equipment check the siren and the bus
Symptoms you may notice3
- The alarm gives false alarms
- The alarm does not sound, and no visible or audible signal appears
- Yellow warning symbol and text message in the display
General guidance for car owners. Diagnosis on the car can point to a different cause.