VOLVO
CEM-5F11 - Relay, auxiliary 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–)
Show models by year and engine (10)
- Volvo S60 (2001–2009)2001
- 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
- Volvo S80 (1999–2006)2003–2004All engines except: B5254T2
- Volvo V70 (2000–2008)2000–2003
- Volvo V70 (2000–2008)2004All engines except: B5254T4
- Volvo V70 XC / XC70 (2001–2007)2001–2004
- Volvo XC90 (2003–)2003–2004
What does this fault code mean?
The auxiliary heater relay is an electrical switch controlled by the CEM, and the fault code is only stored when the relay is activated. The module has then registered a short between the auxiliary heater and battery voltage. The fault is intermittent, so it may have occurred earlier without being active now, and it causes poor interior heating.
Possible causes
- Auxiliary heater relay circuit short-circuited to voltage
What you can do
- 1Clear the code and road test with the auxiliary heater switched on to see whether the fault returns
- 2Check that the relay is firmly seated in its holder and is not damaged or corroded
- 3Check the auxiliary heater fuse and replace it if it has blown
- 4Use a multimeter to check that the relay wire has no contact with voltage supply
- 5Remedy what is found and check that the cabin heating improves
Symptoms you may notice1
- Poor interior heating
General guidance for car owners. Diagnosis on the car can point to a different cause.