VOLVO
CEM-U001088 - Medium Speed CAN Communication Bus. Bus Signal / Message Failures. Bus off
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
Faulty messages are sent or received on the medium speed CAN, and the module has switched itself off the network, so-called bus-off. The cause is most often a break in one or both CAN wires in part of the network, or a short between the internal CAN wires.
Possible causes
- Open circuit in one or both CAN wires in part of the medium speed network
- Short circuit between the internal CAN wires
What you can do
- 1Clear the fault codes, start the car and read them again. If bus-off returns straight away, the fault is active
- 2Check the harness on the medium speed network for breaks, chafing and pinch damage
- 3Check the network connectors for loose connections, corrosion and moisture
- 4With a diagnostic tool, read the fault codes from all control modules. The module that has gone into bus-off often shows no other faults
- 5Gently flex the harness with the ignition on and see whether the fault code changes
- 6Have a workshop measure the resistance on the network, since the network must be separated
Symptoms you may notice4
- The instrument and button lighting does not work
- Some gauges show faults
- The central locking does not work
- The climate control does not work
What the fault can affect2
- The module switches itself off (bus-off) and stays off until its power supply is cut
- At the next power-up the module makes new attempts to communicate
General guidance for car owners. Diagnosis on the car can point to a different cause.