VOLVO
CEM-B103C87 - Left Headlamp Control. Bus Signal / Message Failures. Missing message
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?
The central electronic module (CEM) is waiting for messages from the left main headlamp control unit (LHCU) and receives none. The fault code is stored when the messages are missing, and the headlamp adjustment then cannot be checked.
Possible causes
- Contact resistance, oxidation or loose connections in connectors or joints
- Damaged left main headlamp control unit (LHCU)
- Break in the communication bus to the control unit
- Break in the earth connection or supply to the control unit
What you can do
- 1Check that the connectors to the left headlamp are secure and dry
- 2If you have a diagnostic tool, check whether the left headlamp control unit appears in the list of control units and responds
- 3With the ignition on, use a multimeter to check whether the earth connection and supply to the left headlamp are intact
- 4Clear the fault code and road test. If it returns, have a workshop check the wiring and control unit with diagnostic equipment
- 5If the fault only shows up now and then, it may be a temporary disturbance. Have a workshop assess it if it returns
Symptoms you may notice4
- Headlamp side adjustment does not follow the steering wheel correctly, or does not work
- Headlamp height adjustment is wrong or does not work
- Amber warning symbol and text message in the display
- Main beam with automatic high beam control does not work
What the fault can affect2
- The headlamp light range is held constant
- Side adjustment is locked in the straight-ahead position
General guidance for car owners. Diagnosis on the car can point to a different cause.