VOLVO
CEM-B112C83 - Interior motion sensor. 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?
The interior motion sensor is part of the alarm system. The CEM communicates with it over a shared LIN bus. The code is stored when the message from the sensor is incorrect. The alarm then does not start, and no visible or audible signal is given.
Possible causes
- Contact resistance, oxidation or looseness in connectors or connections
- Damaged movement sensor (IMS)
What you can do
- 1If you have a diagnostic tool: check whether the CEM has other fault codes ending in 86 or 88 and deal with those first, since they point to the LIN bus
- 2Check that the connectors to the interior motion sensor are secure and free from oxidation
- 3Check that the relevant fuses are intact. Their locations are in the owner's manual or on the fuse box cover
- 4If you have a diagnostic tool: read the motion sensor status in live data and check that it responds
- 5If the fault returns, have a workshop with diagnostic equipment check the bus and the sensor, and replace the sensor if needed
Symptoms you may notice1
- The alarm does not start and gives no visible or audible signal
General guidance for car owners. Diagnosis on the car can point to a different cause.