VOLVO
CEM-B10EA12 - Positive temperature coefficient heater. General Electrical Failures. Circuit short to battery
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
In some markets, diesel cars have an electric additional heater (PTC element). The CEM controls the power drawn by the heater through an output. The code is stored when the signal from the output is too high, which is caused by the signal cable having contact with supply voltage. Heating of the cabin then becomes weaker.
Possible causes
- The signal cable has contact with supply voltage
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
- 2Check the cable to the additional heater for chafing and pinch damage
- 3Use a multimeter to check whether the cable to the additional heater has voltage when the heater should be switched off
- 4Check that the connectors in the cable are secure and not oxidised
- 5If the fault returns, have a workshop with diagnostic equipment check the wiring and the control module
Symptoms you may notice5
- Poor heating in the cabin
- Heating in the front section is not warm enough
- Heating in the front section comes on slowly
- Heating in the rear section is not warm enough
- Heater does not work
What the fault can affect3
- The additional heater switches off in the driving cycle in which the fault is detected
- If the fault remains, it switches off permanently after 100 driving cycles
- Clearing the fault codes and starting a new driving cycle resets the output
General guidance for car owners. Diagnosis on the car can point to a different cause.