VOLVO
CEM-5B08 - Right seat heater. Signal too high. Intermittent fault
System
Central Electronic Module (CEM)
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 central electronic module (CEM) has registered that the signal is high or faulty on the wiring to the right seat heater. The fault is intermittent, meaning it comes and goes, so it may have arisen earlier without being active now. The cause may be a short to positive in the wire or a faulty output stage.
Possible causes
- Short to positive in the wiring to the right seat heater
- Output signal constantly high while communication is active
What you can do
- 1Clear the code and road test with the seat heater switched on to see whether the fault returns
- 2Check the connectors in the cable to the right seat heater for loose connections and corrosion
- 3Check that the wiring under the seat is free from chafing and pinching
- 4Check the fuse for the seat heater and replace it if it has blown
- 5Use a multimeter to check that the wire to the right seat heater has no contact with battery voltage
Symptoms you may notice1
- The heating in the front right seat does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.