VOLVO
CEM-DD40 - Communication with the steering wheel module (SWM). Communication fault
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?
The steering wheel module (SWM), which takes in the signals from the controls in the steering wheel, cannot communicate with the central module. Several functions may be affected at once: the wipers, the washers, the indicators, cruise control and the steering wheel buttons.
Possible causes
- Short circuit between the LIN wires
- Open circuit in one of the LIN wires
- Fault in another unit on the same LIN network
What you can do
- 1Check the wipers, washers, indicators, cruise control and the steering wheel buttons, and note which ones do not work
- 2The wiring to the steering wheel and steering wheel module sits close to the airbag. Work there involves the airbag, so have a workshop check it
- 3If the fault remains, have a workshop replace the steering wheel module (SWM)
- 4Indicators are important for road safety, so do not drive with a faulty indicator switch without having it fixed
Symptoms you may notice4
- The wipers only work at the lowest speed
- Washing of the windscreen or rear screen does not work
- The indicator switch does not work
- Cruise control does not work at all
General guidance for car owners. Diagnosis on the car can point to a different cause.