VOLVO
CEM-8A04 - Main beam relay. Signal missing. 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 main beam relay must not be activated for this code to be set. CEM then registers that the high beam circuit is not closed, meaning there is a break. The fault is intermittent and may have occurred earlier without being active now, and the front lamps then do not work.
Possible causes
- Open circuit in the main beam relay circuit
What you can do
- 1Check that the main beam relay is correctly fitted in the fuse box
- 2Check the connections to the relay for loose connections and corrosion
- 3With the ignition off, use a multimeter to check that the wire to the relay has no break
- 4Remedy what is found and check that the high beam works again
Symptoms you may notice1
- Front lamps do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.