VOLVO
CEM-B112E22 - Twilight sensor. General Signal Failures. Signal too high
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 CEM receives information about the light conditions from the twilight sensor and uses it for the brightness of the symbols and instrument lighting. The code is stored when the signal level from the twilight sensor is too high, which is caused by the signal cable touching supply voltage or by the sensor not working. The instrument and button lighting then does not work.
Possible causes
- The signal cable touches supply voltage
- The twilight sensor does not operate
What you can do
- 1Check that the relevant fuses are intact. Their locations are in the owner's manual or on the fuse box cover
- 2Use a multimeter to check whether the signal cable to the twilight sensor has voltage when the ignition is off
- 3Look for chafing and pinch damage on the signal cable to the sensor
- 4If you have a diagnostic tool: read the twilight sensor value in live data and check that it changes when the light changes
- 5If the fault returns, have a workshop with diagnostic equipment check the sensor and the wiring
Symptoms you may notice1
- Instrument and button lighting does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.