VOLVO
CPM-B1D2311 - Overheat Sensor. General Electrical Failures. Circuit short to ground
System
Combustion Pre-heater Module (CPM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsV40 (2013–), V40 Cross Country (2013–)
Show models by year and engine (2)
What does this fault code mean?
The CPM has logged a signal from the overheat thermostat that reads too low. This may be caused by the cable being shorted to earth, poor connections or a damaged thermostat. The heater cannot be activated until the fault code has been cleared.
Possible causes
- The cable between the CPM and the overheat protection thermostat is shorted to earth
- Contact resistance, oxidation or loose connections
- Damaged overheat protection thermostat
What you can do
- 1Clear the code and check whether it returns when the ignition is switched on
- 2Disconnect the connector at the overheat protection thermostat and check that the contacts are secure and free from oxidation
- 3Use a multimeter to check that the cable has no contact with the body (earth); if it does, the cable is shorted
- 4If you have a diagnostic tool, activate the heater and check that the temperature rises; if it does not, suspect the thermostat
- 5If the fault returns, have a workshop measure the thermostat resistance and check the wiring
Symptoms you may notice1
- 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.