VOLVO
CEM-2E02 - Relay, horn 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?
The CEM has registered that the horn relay is short-circuited to supply voltage. The horn does not work in this case. The fault is most often caused by a broken relay.
Possible causes
- A damaged relay
What you can do
- 1Check the horn fuse in the engine bay fusebox. If it has blown, replace it once
- 2Replace the horn relay with an identical one. If the horn then works, the old relay was probably faulty
- 3Check that the connectors at the relay and at the CEM are seated and not corroded
- 4With the relay removed, use a multimeter to check that the horn wire has no short to supply voltage
- 5After the work, test the horn and check that the code does not return
Symptoms you may notice1
- The horn does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.