VOLVO
CEM-B1A7911 - Rear Fog Lamp Circuit. General Electrical Failures. Circuit short to ground
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 CEM supplies the rear fog lamps directly from an output, and the fault is stored when the wire supplying the fog lamps is short-circuited to earth.
Possible causes
- The supply wire is short-circuited to earth
What you can do
- 1Check that the fuses are intact
- 2Check the wiring from the CEM to the rear fog lamps for chafing and pinch damage, particularly where it may have touched the body
- 3Use a multimeter to check that the supply wire has no contact with earth (the body) with the connectors disconnected
- 4Clear the fault code and check whether it returns when the fog lamps are switched on
- 5If the fault returns, have a workshop with diagnostic equipment fault-trace the control module and the wiring
Symptoms you may notice2
- The rear fog lamps do not work
- A message appears in the display
What the fault can affect3
- The fog lamps switch off during the driving cycle in which the fault is detected
- If the fault remains, the function is switched off permanently after 100 driving cycles where the fault was detected
- Erasing fault codes or starting a new driving cycle resets the output
General guidance for car owners. Diagnosis on the car can point to a different cause.