VOLVO
CEM-5F4F - Start attempt. Too many unsuccessful attempts
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 (8)
- Volvo S60 (2001–2009)2001, 2005–2009
- Volvo S60 (2001–2009)2002All engines except: D5244T2
- Volvo S60 (2001–2009)2003–2004All engines except: B5244S6, D5244T2
- Volvo S80 (1999–2006)1999–2006
- Volvo V70 (2000–2008)2000–2002, 2005–2008
- Volvo V70 (2000–2008)2003–2004All engines except: B5244S6
- Volvo V70 XC / XC70 (2001–2007)2001–2007
- Volvo XC90 (2003–)2003–2015
What does this fault code mean?
The control unit has indicated that a failed start attempt has taken place, and the central electronic module (CEM) then sets the code. When activated, the heater tries to start, and it makes several more attempts if it fails; the fault is registered when it receives a signal that the start failed. The fault shows when the heater is active.
Possible causes
- No fuel supply to the heater
- Flame sensor covered with soot
- Blocked combustion air flow
- Contact resistance in the control unit connectors
- Open circuit or short to voltage supply in the flame sensor control wire
- Damaged flame sensor
What you can do
- 1Check that there is enough fuel in the tank and that the battery is not weak, as the heater will not start otherwise
- 2Inspect the fuel lines for damage or leakage, and make sure nothing blocks them. Use gloves and eye protection
- 3Check that the air intake and exhaust outlet of the heater are not blocked
- 4Check that the flame sensor is not sooty, and remedy the control unit connectors if they are loose or corroded
- 5Clear the fault codes once fuel and battery are in order, as otherwise the heater locks after three failed starts
Symptoms you may notice2
- Poor interior heating
- Parking heater does not work
What the fault can affect2
- The heater is not activated
- The heater cannot start again until the fault codes have been cleared
General guidance for car owners. Diagnosis on the car can point to a different cause.