VOLVO
CEM-U001700 - Medium Speed CAN Communication Bus (-) High. General Failure Information. No sub type information
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 fault code means that the negative (high) wire in the medium-speed CAN bus has contact with voltage. The bus links the control modules in the car together, and a wire lying against voltage stops messages from getting through properly. The instrument lighting, gauges, central locking and climate control may therefore work poorly or not at all.
Possible causes
- Chafed or pinched wiring lets the negative MS-CAN wire touch a live wire
What you can do
- 1Read the fault codes from all control modules, clear them and road test the car to see whether the code returns
- 2Switch the ignition off and inspect the negative wire for chafing, pinch damage and loose connectors near live cables
- 3With the ignition on, use a multimeter to confirm the negative wire has no contact with voltage. Move the wiring during the test
- 4If the code returns, have a workshop with diagnostic equipment check the bus. Replace the CEM only if testing shows it is faulty
Symptoms you may notice4
- Instrument or button lighting does not work
- Gauges in the instrument panel do not work properly
- Central locking cannot lock or unlock the car
- Temperature control and air conditioning do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.