VOLVO
CEM-B101D12 - Auxiliary Light Relay. General Electrical Failures. Circuit short to battery
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 central electronic module (CEM) controls the power to the auxiliary lights through a control signal. The fault code is stored when the auxiliary lights are powered although they should not be. The auxiliary lights then do not work.
Possible causes
- Supply cable shorted to voltage
What you can do
- 1Check that the fuses for the auxiliary lights are intact
- 2Switch the ignition off, wait a moment and switch it on again to see whether the auxiliary lights work
- 3With the ignition off, check the cable to the auxiliary lights for chafing and pinching, especially where it may have touched a live wire
- 4With the ignition off, use a multimeter to check whether the supply cable has voltage; voltage when the ignition is off means a short to voltage
- 5Remedy the fault and clear the fault code. If it remains, have a workshop check the control module
Symptoms you may notice1
- The auxiliary lights do not work
What the fault can affect1
- The output is switched off for the current drive cycle
General guidance for car owners. Diagnosis on the car can point to a different cause.