VOLVO
CEM-B112C87 - Interior motion sensor. 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 CEM sends and receives information over the LIN bus, and checks the motion sensor. The code is stored when communication with the motion sensor is lost for a set time. The alarm then does not work as it should, and a text message may appear in the display.
Possible causes
- Break in the voltage supply to the movement sensor (IMS)
- Break in the ground lead to the movement sensor (IMS)
- Contact resistance in the connections
- The movement sensor (IMS) does not work
- Break or short circuit on the LIN bus to the movement sensor
- Break in the LIN cable
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 relevant fuses are intact. Their locations are in the owner's manual or on the fuse box cover
- 3Check that the connectors and the ground lead to the motion sensor are secure and not oxidised
- 4Use a multimeter to check that the supply cable to the motion sensor has voltage and is not broken
- 5If the fault returns, have a workshop with diagnostic equipment check the LIN bus, the wiring and the sensor
Symptoms you may notice4
- The alarm does not start and gives no visible or audible signal
- Text message in the display
- The alarm has other problems
- Yellow warning symbol and text message in the display
General guidance for car owners. Diagnosis on the car can point to a different cause.