VOLVO
CEM-E001 - Control module communication. Faulty communication
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
What does this fault code mean?
A module on the low speed network registers a serious disturbance, and CAN communication is blocked. The fault code can only be read out when the fault is intermittent, because the module cannot be reached while the fault is present. The gauges, instrument lighting and remote control may be affected in the meantime.
Possible causes
- Short circuit between CAN wires on the low speed network
- Open circuit in one of the CAN wires on the low speed network
- Internal fault in the module
- Another module in the same part of the CAN network disturbs communication
What you can do
- 1Note which fault codes are stored in which modules, so you can see where the communication breaks
- 2If the CEM holds codes for lost communication, work through those first
- 3Check the connectors on the low speed network for loose connections and corrosion
- 4Gently flex the cable with the ignition on and see whether the communication changes
- 5Use a multimeter to check that the CAN wires have no break when the supply is off. This is best left to a workshop
- 6If a module is still in bus-off after the repair, disconnect the battery negative lead for a while and reconnect it
Symptoms you may notice3
- No gauges are working
- The instrument lighting does not operate
- Cannot be operated with the remote control
What the fault can affect1
- The module switches itself off (bus-off) and stays disabled until the power supply is cut
General guidance for car owners. Diagnosis on the car can point to a different cause.