VOLVO
CEM-U001300 - 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?
On the V40 the positive wire of the medium speed CAN is shorted to earth, which disturbs communication between the control modules. The instrument lighting, gauges, central locking and climate control can then be affected. The fault most often lies in the wiring where it may have rubbed against the body.
Possible causes
- Short circuit between the positive wire of the medium speed CAN and earth
What you can do
- 1Note which functions have dropped out. Several systems dropping out at once points to a fault in the network
- 2Check the harness for chafing and pinch damage where it may have touched the body
- 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 positive wire has no contact with earth or the body along its length
- 6Gently flex the cable with the ignition on and see whether the functions change
Symptoms you may notice4
- The instrument and button lighting does not work
- Some gauges do not work properly
- The central locking does not work
- The climate control does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.