VOLVO
CEM-1A03 - S-Power supply. Signal too low. Intermittent 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 CEM has registered an open circuit or a short to ground in the S-supply from the ignition switch, and the fault is intermittent. This means it was present at an earlier time but is no longer there. The starter motor may then work at times and fail at others.
Possible causes
- Contact resistance in the terminals
- Open circuit or short to ground in the S-supply
- The key is not recognised
- Defective ignition switch
What you can do
- 1Check that the connectors at the CEM and the ignition switch are secure and free from corrosion
- 2Lightly move the wiring at the connectors and see whether the fault returns
- 3Check with a multimeter that the wire reads battery-level voltage with the key in the ignition switch
- 4If the fault returns, have a workshop replace the ignition switch
Symptoms you may notice1
- The starter motor does not turn
General guidance for car owners. Diagnosis on the car can point to a different cause.