VOLVO
CEM-B1C7719 - Rear Wiper Relay. General Electrical Failures. Circuit current above threshold
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsV40 (2013–), V40 Cross Country (2013–)
Show models by year and engine (2)
What does this fault code mean?
The central electronic module (CEM) controls the rear wiper through a relay in the engine bay fuse box. The code is set when the signal wire to the relay is shorted to voltage, so the control module detects that the circuit is drawing too much current.
Possible causes
- Short to voltage on the signal wire
What you can do
- 1Read and clear the code, then run the rear wiper and see whether the fault comes back
- 2Check the rear wiper fuse in the engine bay fuse box; a blown fuse is a sign that the circuit is overloaded
- 3Use a multimeter to see whether the signal wire has voltage with the ignition off, which shows contact with a live wire
- 4Look for chafed cables or damaged insulation on the wire between the control module and the relay, especially where it may have been pinched
- 5If the wire is sound, have a workshop with diagnostic equipment check the relay and the control module
Symptoms you may notice1
- The rear wiper does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.