VOLVO
CEM-B1D1A12 - Interior Lights Circuit "C". General Electrical Failures. Circuit short to battery
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
7 modelsS60 (2011–), S80 (2007–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The central electronic module (CEM) supplies the roof lighting through circuit C. The code is set when the signal from the output is too high, which is caused by the supply wire being shorted to voltage.
Possible causes
- The supply wire to the roof lighting is shorted to voltage
What you can do
- 1Read and clear the code and switch on the roof lighting to see whether it works
- 2Check that the fuse for the roof lighting is intact
- 3Use a multimeter to see whether the supply wire has voltage with the ignition off
- 4Look for chafing on the supply wire to the roof lighting, especially where the cable may have been pinched
- 5If the wire is intact, have a workshop with diagnostic equipment check the module output
Symptoms you may notice2
- The roof lighting does not work
- The roof lighting does not switch off when the engine is running
What the fault can affect3
- The function switches off during the driving cycle in which the fault is detected
- After repeated driving cycles with the fault, the function is switched off permanently
- Clearing the fault codes and starting a new driving cycle resets the output
General guidance for car owners. Diagnosis on the car can point to a different cause.