VOLVO
CEM-B11DB87 - Battery Monitoring Module. Bus Signal / Message Failures. Missing message
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
7 modelsS60 (2011–), S80 (2007–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The battery monitoring sensor (BMS) measures the battery status and sends the data to the CEM, which controls alternator charging. The fault is stored when messages from the sensor are missing on the LIN bus, and The cause may be an open circuit in the LIN connection, a damaged sensor, or a fault in another control module on the same part of the LIN network.
Possible causes
- Open circuit in the LIN connection between the CEM and the battery monitoring sensor
- Damaged battery monitoring sensor
- Internal fault in another control module on the same part of the LIN network
What you can do
- 1Check that the fuses are intact
- 2Check that the sensor receives power from the battery positive and that the wire has no breaks or short circuits to earth
- 3Check the signal wire between the sensor and the CEM for intermittent short circuits to earth and for oxidised or loose connectors
- 4Have a workshop with diagnostic equipment check whether another control module on the LIN bus is blocking communication
- 5If no fault is found in the wiring, the sensor probably needs replacing, which is a job for a workshop
Symptoms you may notice3
- The automatic start/stop function does not work while driving or at idle
- A red warning symbol and a text message appear in the display
- The charging warning lamp does not work as it should
General guidance for car owners. Diagnosis on the car can point to a different cause.