VOLVO
CPM-1128 - Combustion fan. Signal too low
System
Combustion Pre-heater Module (CPM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The CPM has registered a signal that is too low on the cable to the combustion fan. The cause may be a short circuit to earth in the cable, or a fan wheel that has jammed, for example from frost or dirt. The heater cannot be activated until the code has been cleared.
Possible causes
- The cable between the CPM and the combustion fan is shorted to earth
- The fan wheel of the combustion fan has jammed, for example from frost or dirt
What you can do
- 1Check that the fan wheel in the combustion fan turns freely by hand; if it is stuck with dirt or ice, clear it carefully
- 2Clear the code and start the heater again
- 3If you have a diagnostic tool, activate the combustion fan and listen for a buzzing sound; if there is none, the fault is probably permanent
- 4Use a multimeter to check that the cable has no contact with the body (earth); if it does, the cable is shorted
- 5If the fault remains, have a workshop check the combustion fan and the wiring
Symptoms you may notice2
- Poor heating in the passenger compartment
- The parking heater does not work
What the fault can affect1
- The heater cannot be activated until the fault code has been cleared
General guidance for car owners. Diagnosis on the car can point to a different cause.