VOLVO
CEM-U001600 - Medium Speed CAN Communication Bus (-) Low. 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 (low) wire in the medium-speed CAN bus has contact with ground, meaning the car body. The bus is the network the control modules use to exchange information, and a grounded wire disturbs those messages. The instrument and button lighting, gauges, central locking and climate control can then stop working as they should.
Possible causes
- Chafed or pinched wiring lets the negative MS-CAN wire touch the car body
What you can do
- 1Read and note the fault codes in the control modules, clear them and road test the car to see whether the code returns
- 2Switch the ignition off and check the negative wire for chafing and pinch damage, especially where it can touch body metal
- 3With the battery negative lead disconnected, use a multimeter to confirm the wires have no contact with ground. Wiggle connectors 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.