VOLVO
CEM-8C10 - Relay, front fog lamps. Signal too high
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?
Although the code is named too high signal, the central electronic module (CEM) registers too low a power consumption at the output that feeds the front fog lamp relay. The fault comes from the signal wire to the relay having contact with battery voltage. On vehicles with daytime running lights, the relay instead feeds the fog lamps, and troubleshooting is the same.
Possible causes
- The signal wire to the front fog lamp relay is short-circuited to battery voltage
What you can do
- 1Switch the fog lamps on and then off. A click from the relay when the fog lamps are switched off shows that the relay is working
- 2If the fog lamps cannot be switched off, the fault is most likely permanent. If they can but the code was stored earlier, the fault is intermittent
- 3Switch the ignition off and check that the relay is correctly fitted and that its contacts are clean
- 4With the ignition off, use a multimeter to check that the wire to the relay has no contact with battery voltage
- 5If the fault remains, have a workshop replace the relay and check the circuit
Symptoms you may notice1
- The front fog lamps do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.