VOLVO
CEM-B1C5514 - Horn Relay. General Electrical Failures. Circuit short to ground or open
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
6 modelsS80 (2007–), V40 (2013–), V40 Cross Country (2013–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The CEM controls the horn relay and checks the drive signal to it. The fault is stored when the signal is too low or missing when the horn is activated. The cause may be a relay drive circuit short-circuited to earth, a break in the signal wire, or a damaged relay itself.
Possible causes
- The relay drive circuit is short-circuited to earth
- Break in the signal wire to the relay drive circuit
- Damaged relay with a short circuit in the relay coil
What you can do
- 1Check that the fuse for the horn is intact
- 2Activate the horn and check whether it sounds, then clear the fault code and road test
- 3Check the signal wire to the relay for breaks and chafing
- 4Use a multimeter to check that the signal wire has no contact with earth (the body) with the connectors disconnected
- 5If the fault returns, have a workshop check the relay and the control module
Symptoms you may notice1
- The horn does not work
What the fault can affect2
- The function switches off permanently after 100 driving cycles where the fault was detected
- Erasing the fault codes resets the output
General guidance for car owners. Diagnosis on the car can point to a different cause.