VOLVO
CEM-5F40 - Fuel pump. 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 that the signal in the fuel pump circuit is too low. The cause may be poor contact, an open circuit or earth fault in the wiring, a damaged fuel pump or a damaged overheat protection thermostat. The fault shows when the heater is active and causes poor heating in the passenger compartment.
Possible causes
- Contact resistance in the control unit or fuel pump connector
- Signal wire short-circuited to ground
- Open circuit in the signal or voltage wire
- Damaged fuel pump
- Damaged overheat protection thermostat
What you can do
- 1Read and note the code, clear it and activate the heater to see whether the fault returns
- 2Check the connectors at the fuel pump and the control unit for loose connections and corrosion, and remedy if needed
- 3If the heater works again after the connectors are repaired, the fault was probably poor contact
- 4Have a workshop check the overheat protection thermostat and replace it if it is damaged
- 5Use a multimeter to check that the wires to the fuel pump have no break and no contact with ground (the body)
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.