VOLVO
CEM-2F61 - Twilight sensor. Signal too low
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The CEM receives light information from the twilight sensor and uses it to set the brightness of the instrument lighting. The fault means the signal wire is short-circuited to ground, so the signal is too low. The night light level is then used, and the instrument lighting may not behave correctly.
Possible causes
- The signal wire is short-circuited to ground
- The twilight sensor is not working
What you can do
- 1Check that the connector at the CEM and at the twilight sensor is seated and not corroded
- 2Cover the twilight sensor with your hand, then shine a torch on it. If the instrument lighting clearly changes brightness, the sensor is probably fine
- 3Use a multimeter to check that the signal wire to the twilight sensor is not short-circuited to ground
- 4If the wire is intact and the fault remains, replace the twilight sensor with an identical one
- 5After the work, clear the code and check that the instrument lighting works
Symptoms you may notice1
- Instrument panel lighting is out
What the fault can affect1
- The night light level is used
General guidance for car owners. Diagnosis on the car can point to a different cause.