VOLVO
CEM-5F41 - Overheat thermostat. 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 (12)
- Volvo S60 (2001–2009)2001, 2005–2009
- Volvo S60 (2001–2009)2002All engines except: D5244T2
- Volvo S60 (2001–2009)2003All engines except: B5244S6, B5254T2, D5244T2
- Volvo S60 (2001–2009)2004All engines except: B5244S6, B5254T2, B5254T4, D5244T2
- Volvo S80 (1999–2006)1999–2002, 2005–2006
- Volvo S80 (1999–2006)2003–2004All engines except: B5254T2
- Volvo V70 (2000–2008)2000–2002, 2005–2008
- Volvo V70 (2000–2008)2003All engines except: B5244S6, B5254T2
- Volvo V70 (2000–2008)2004All engines except: B5244S6, B5254T2, B5254T4
- Volvo V70 XC / XC70 (2001–2007)2001–2002, 2005–2007
- Volvo V70 XC / XC70 (2001–2007)2003–2004All engines except: B5254T2
- Volvo XC90 (2003–)2003–2015
What does this fault code mean?
The overheat protection thermostat in the heater has tripped, and the central electronic module (CEM) treats this as a fault and sets the code. The thermostat trips when the heater becomes too hot, for example when the flow of water through it is restricted. The fault shows when the heater is active and causes poor heating in the passenger compartment.
Possible causes
- Air in the cooling system
- Cooling system blocked
- Defective overheat protection thermostat
- Defective water temperature sensor
- Open circuit in the fuel pump circuit
What you can do
- 1Read and note the code, clear it and start the heater to see whether the fault returns
- 2Check that the hoses to and from the heater are not blocked, kinked or damaged
- 3Check that the coolant level is correct and that the cooling system contains no air
- 4If you have a diagnostic tool, read the water temperature in the heater in live data and compare it with the engine temperature with the engine running
- 5Have a workshop check the overheat protection thermostat and replace it if it is damaged
Symptoms you may notice1
- Poor heating in the passenger compartment
General guidance for car owners. Diagnosis on the car can point to a different cause.