VOLVO
CEM-B103D83 - Right Headlamp Control. Bus Signal / Message Failures. Value of signal protection calculation incorrect
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?
Central electronic module (CEM) and the right main headlamp control unit (RHCU) communicate over the LIN bus. The fault code is stored when the data from the RHCU becomes incorrect in transmission, and the right headlamp adjustment and high beam can then be affected.
Possible causes
- Contact resistance, oxidation or loose connections in connectors or joints
- Damaged right main headlamp control unit (RHCU)
What you can do
- 1Check the connectors and wiring to the right headlamp for oxidation and looseness, and gently move the wiring with the ignition on
- 2With a diagnostic tool, check for other fault codes in the same control unit that end in 86 or 88, and deal with them first
- 3Clear the fault code and road test. If it returns, have a workshop check the control unit, since this needs diagnostic equipment and sometimes new software
- 4After the repair, check that the headlamp adjustment works, and have a workshop adjust it if needed
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 level
- Side adjustment locks in the straight-ahead position
General guidance for car owners. Diagnosis on the car can point to a different cause.