VOLVO
CEM-B103D16 - Right Headlamp Control. General Electrical Failures. Circuit voltage below threshold
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
7 modelsS60 (2011–), S80 (2007–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The right main headlamp control unit (RHCU) receives too low a voltage, according to the fault code. It drives the headlamp motors, so side and height adjustment and automatic high beam can be affected. The cause may be a fault in the supply or a damaged control unit.
Possible causes
- Incorrect voltage supply to the right main headlamp control unit (RHCU)
- Supply wire shorted to earth or voltage
- Damaged right main headlamp control unit (RHCU)
What you can do
- 1Check that the fuses for the headlamps are intact
- 2With the ignition on, use a multimeter to check the supply to the right headlamp. Too low a voltage, or none, points to a supply fault
- 3With the ignition off, check whether the supply wire has contact with earth or voltage, since that can give too low a voltage at the control unit
- 4Remedy the fault and clear the fault code. If it returns, have a workshop check the right headlamp control unit
Symptoms you may notice4
- Side adjustment of the right headlamp does not follow the steering wheel correctly, or does not work
- Height adjustment of the right headlamp is wrong or does not work
- A message appears in the information display
- Main beam with automatic high beam control does not work
What the fault can affect2
- The light range is held in a fixed setting
- Side adjustment locks in the straight-ahead position
General guidance for car owners. Diagnosis on the car can point to a different cause.