VOLVO
CEM-5B05 - Left seat heater. Signal too low. 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 to the left seat heater is too low or missing. The fault is intermittent, so it has occurred before but may not be active now. The cause may be an earth fault or an open circuit in the wiring to the seat heater, or a low signal when the communication link is not active.
Possible causes
- Earth fault or open circuit in the wiring to the left seat heater
- Low input signal when the communication link is not activated
What you can do
- 1Clear the code and road test with the seat heater switched on to see whether the fault returns
- 2Check that the wiring to the left seat heater has no chafing or pinching, especially under the seat
- 3Check the connectors in the seat heater cable for loose connections and corrosion
- 4Check the fuse for the seat heater and replace it if it has blown
- 5Use a multimeter to check that the wiring to the left seat heater has no break and no contact with ground (the body)
Symptoms you may notice1
- Front seat heating on the left does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.