VOLVO
CEM-5F3D - Heater fan. Signal too low
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–)
Show models by year and engine (10)
- Volvo S60 (2001–2009)2001, 2005–2009
- Volvo S60 (2001–2009)2002All engines except: D5244T2
- Volvo S60 (2001–2009)2003All engines except: B5244S6, D5244T2
- Volvo S60 (2001–2009)2004All engines except: B5244S6, B5254T4, D5244T2
- Volvo S80 (1999–2006)1999–2002, 2005–2006
- Volvo S80 (1999–2006)2003–2004All engines except: B5254T2
- Volvo V70 (2000–2008)2000–2003, 2005–2008
- Volvo V70 (2000–2008)2004All engines except: B5254T4
- Volvo V70 XC / XC70 (2001–2007)2001–2007
- Volvo XC90 (2003–)2003–2015
What does this fault code mean?
The central electronic module (CEM) has registered too low a signal or no signal from the heater fan in the parking heater. This can be caused by contact faults, breaks in the wiring, a short to ground or a defective fan. The fault shows when the heater is active and gives poor heating in the passenger compartment.
Possible causes
- Contact resistance in the control unit or fan connector
- Open circuit in the signal or voltage wire
- Signal wire short-circuited to ground
- Defective heater fan
What you can do
- 1Read and note the code, clear it and activate the heater fan to listen for a buzzing sound
- 2Check the connectors at the fan and the control unit for loose connections and corrosion, and remedy if needed
- 3If the fan works again after the connectors are repaired, the fault was probably poor contact
- 4Use a multimeter to check that the wires to the heater fan have no break and no contact with ground (the body)
- 5If the wiring is intact and the fault remains, a workshop should replace the heater fan
Symptoms you may notice2
- Poor interior heating
- Parking heater does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.