VOLVO
CEM-8F62 - Relay, heated rear windshield. 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 too high a signal on the driver circuit for the rear defroster relay. The rear window heating then does not work, because the signal wire has come into contact with voltage.
Possible causes
- Short to supply voltage
What you can do
- 1Test the rear window defroster with the ignition on: if it does not start the fault is permanent, and if it starts the fault has occurred before
- 2Check that the rear defroster relay sits firmly and is not loose
- 3Use a multimeter to check that the signal wire has no contact with voltage when the ignition is off
- 4Look for chafing on the signal wire where it may have touched voltage
- 5If the fault returns, have a workshop repair the wire or replace the relay
Symptoms you may notice1
- The rear window heating does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.