VOLVO
CEM-DE30 - Communication with the electric power steering module (EPS). Signal missing
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The CEM has lost contact with the electric power steering module (EPS), so the power steering assistance is not controlled. The fault comes from supply, earth or a connector at the EPS module, or from a break in the CAN high speed network. The CEM showing the fault does not mean the CEM is faulty.
Possible causes
- No supply to the EPS module
- Open circuit in the earth wire to the EPS module
- Poor contact in the connections
- Open circuit in the CAN high speed wires to the EPS module
- The EPS module does not suit the car, for example a used module with different software or hardware
What you can do
- 1Check the main battery fuse and the power steering fuses in the engine bay and in the CEM. If one has blown, check its circuit for a short to earth
- 2Use a multimeter to check that the supply wire to the EPS module has no break and is not shorted to earth
- 3Check that the earth point for the EPS module is secure and not oxidised
- 4With a diagnostic tool, read the EPS module ID. If it reads, the communication is probably fine and the fault may be intermittent
- 5Power steering is a safety function. Have a workshop repair the fault promptly rather than putting it off
Symptoms you may notice1
- The electric power steering does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.