VOLVO
REM-4F90 - Sensor, seat belt reminder. Signal too high
System
Rear Electronic Module (REM)
Volvo models this fault code applies to
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 rear electronic module (REM) reads the signal from the seat belt reminder sensor in the passenger seat. If that signal is too high, the code is set. The cause can be a signal wire shorted to supply voltage or a defective sensor, and a general warning lamp then lights.
Possible causes
- Signal wire shorted to supply voltage
- Defective seat belt reminder sensor
What you can do
- 1Read and note the fault code, clear it and test drive the car to see whether it returns
- 2Check the connectors at the rear electronic module and at the seat belt reminder sensor in the passenger seat for oxidation, damage and loose contacts
- 3Look for an intermediate connector in the wiring to the sensor and check it
- 4Use a multimeter to check that the signal wire to the seat belt reminder sensor has no contact with supply voltage when the ignition is off
- 5If the fault remains, have a workshop replace the seat belt reminder sensor
Symptoms you may notice1
- General warning lamp lit
General guidance for car owners. Diagnosis on the car can point to a different cause.