VOLVO
CEM-B1C8414 - Heated rear window relay output circuit. General Electrical Failures. Circuit short to ground or open
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
4 modelsS80 (2007–), V70 (2008–), XC60 (2009–), XC70 (2008–)
Show models by year and engine (4)
What does this fault code mean?
The central electronic module (CEM) controls the rear window defroster. The code is set when the signal from the output is too low, which can be caused by the supply wire being shorted to ground or having an open circuit.
Possible causes
- The supply wire to the rear window heater is shorted to ground
- Open circuit on the supply wire to the rear window heater
What you can do
- 1Read and clear the code, then see whether the rear window heater works after it is switched on
- 2Check the rear window heater fuse and make sure it is intact
- 3Use a multimeter to check that the supply wire has no contact with ground (the bodywork)
- 4Use a multimeter to check that the supply wire is continuous between its two ends
- 5If the wire is intact, have a workshop with diagnostic equipment check the module output
Symptoms you may notice1
- Electric heating of the rear window does not work
What the fault can affect2
- The function switches off permanently after repeated driving cycles in which the fault was detected
- Clearing the fault codes resets the output
General guidance for car owners. Diagnosis on the car can point to a different cause.