VOLVO
CEM-B109714 - Heated Windshield 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:
2 modelsV40 (2013–), V40 Cross Country (2013–)
Show models by year and engine (2)
What does this fault code mean?
The CEM controls the front windscreen defroster through a relay. The fault shows that the relay supplying the defroster stays closed although the defroster is not switched on, so the defroster receives power unnecessarily. The fault is checked when the ignition is on and the defroster is not activated.
Possible causes
- The control wire to the defroster relay is shorted to ground
- Open circuit in the control wire to the defroster relay
What you can do
- 1Read off and note the code, clear it and check whether it returns when you switch the defroster on
- 2Check that the fuses for the front windscreen defroster are intact
- 3Check that the connectors in the defroster wiring harness are fully engaged and not corroded
- 4Use a multimeter (ignition off, connector unplugged) to check that the relay control wire has no connection to ground and no break
- 5If you have a diagnostic tool, activate the front windscreen defroster with the tool and check whether it starts
- 6If the fault remains, have a workshop check the relay and the wiring
Symptoms you may notice1
- Windscreen defog and defrost does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.