VOLVO
CEM-8F51 - Relay, headlamp wash / wipe. Signal too low
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?
Although the code is named signal too low, it means the relay coil for the headlamp washing gets too high a signal. The headlamp washer motor then does not work, caused by a signal wire shorted to supply voltage or by a damaged relay.
Possible causes
- Signal wire short-circuited to supply voltage
- Damaged relay
What you can do
- 1Replace the headlamp washing relay and activate the windscreen washer: if the high-pressure washing then works, the old relay was damaged
- 2Clear the code and check whether it returns with the ignition on
- 3Look for chafing on the signal wire where it may have touched voltage
- 4Use a multimeter to check that the signal wire has no contact with voltage when the ignition is off
- 5If no fault is found, have a workshop check the fuse box and the wiring
Symptoms you may notice1
- The headlamp washer motor does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.