VOLVO
CEM-B101C86 - Right Headlamp Control. Bus Signal / Message Failures. Signal invalid
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 right main headlamp control unit (RHCU) sends incorrect data to the central electronic module (CEM) over the LIN bus. The fault code is stored when the data does not match, and it mainly affects headlamp adjustment and automatic high beam.
Possible causes
- Contact resistance, oxidation or loose connections in connectors or joints
- Internal fault in the right main headlamp control unit (RHCU)
What you can do
- 1Check the connector to the right headlamp for oxidation and loose connections, and gently move the wiring with the ignition on
- 2If you have a diagnostic tool, see whether the side adjustment of the right headlamp changes in live data when you turn the steering wheel
- 3Clear the fault code and road test. If the beam setting is wrong once the fault has gone, have a workshop adjust the headlamp
- 4If the fault remains, have a workshop check the control unit for the right headlamp
Symptoms you may notice3
- 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
- Main beam with automatic high beam control does not work
What the fault can affect2
- The light range stays fixed at one constant level
- Side adjustment is locked in the straight-ahead position
General guidance for car owners. Diagnosis on the car can point to a different cause.