VOLVO
CEM-U001012 - Medium Speed CAN Communication Bus. General Electrical Failures. Circuit short to battery
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
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?
One of the medium speed CAN wires is shorted to supply voltage, which disturbs communication between the control modules. The instrument lighting, central locking and climate control can then work poorly or not at all. The fault most often lies in the harness.
Possible causes
- Short circuit between one of the medium speed CAN wires and supply voltage
What you can do
- 1Check whether several functions drop out together. That points to a shared fault on the medium speed network
- 2Check the harness for chafing, pinch damage and moisture where it moves
- 3Check the connectors on the network for loose connections and corrosion
- 4With a diagnostic tool, read the fault codes from all control modules and see which ones show communication faults
- 5Use a multimeter to check that the medium speed wires do not touch supply voltage when they are moved
- 6Gently flex the harness with the ignition on and see whether the functions change
Symptoms you may notice4
- The instrument and button lighting does not work
- Some gauges show faults
- The central locking does not work
- The air conditioning does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.