VOLVO
REM-8C21 - Relay, rear fog lamp. Signal too high. Intermittent fault
System
Rear Electronic Module (REM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
What does this fault code mean?
The fault is intermittent, meaning it is sporadic and may not be present right now. The rear electronic module (REM) has registered too high a signal from the status flag when it activates the rear fog lamp relay, which can mean a brief short to battery voltage in the relay control. The rear fog lamp does not work.
Possible causes
- The control to the rear fog lamp relay is shorted to battery voltage
What you can do
- 1Read and clear the fault code, then check whether it returns when the fog lamp is switched on
- 2Check that the rear fog lamp relay is correctly fitted
- 3Check the relay connections for oxidation, contact resistance and loose contacts
- 4Use a multimeter to check that the relay control wire has no contact with battery voltage, and repeat the check if the fault comes and goes
- 5If the fault remains, have a workshop with diagnostic equipment investigate the relay and the wiring
Symptoms you may notice1
- The rear fog lamp does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.