VOLVO
CEM-5E01 - Sun sensor. Faulty signal
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 central electronic module (CEM) has registered a fault in the sun sensor circuit, either a short to battery voltage or an open circuit in the wiring. The sun sensor measures how much sunlight hits the car, so a fault means the climate system cannot adjust the cabin temperature correctly.
Possible causes
- Defective sun sensor
- Short to battery voltage or open circuit in the wiring to the sun sensor
What you can do
- 1Read and clear the code, then check whether the climate system works normally again
- 2Cover the sun sensor by hand, then light it with a flashlight from close range; if the climate system does not react, the wiring is probably open or the sensor faulty
- 3Check the sun sensor connector for loose connections and corrosion
- 4Use a multimeter to check that the sun sensor wire is not broken and has no contact with battery voltage
- 5If the wiring is intact and the fault remains, a workshop should replace the sun sensor
Symptoms you may notice2
- Passenger compartment temperature is not reduced in strong sunlight
- Passenger compartment temperature does not match the set position
General guidance for car owners. Diagnosis on the car can point to a different cause.