VOLVO
CEM-DD31 - Communication with the rain sensor module (RSM). Signal missing
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 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The central module gets no communication from the rain sensor (RSM), so the rain sensor stops working. The cause may be a broken supply or ground wire to the rain sensor, contact resistance at the connections, or a faulty rain sensor.
Possible causes
- Break in the supply feed to the rain sensor (RSM)
- Break in the earth wire to the rain sensor (RSM)
- Contact resistance at the connections
- The rain sensor is not working
What you can do
- 1Check that the rain sensor fuse is intact, using the owner's manual. If it is blown, check for a short to ground in the circuit after it before replacing it
- 2Follow the wires to the rain sensor for breaks and chafing, and clean and tighten the connectors
- 3If the wires are intact, have a workshop replace the rain sensor
Symptoms you may notice1
- The rain sensor does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.