VOLVO
CPM-B1D2315 - Overheat Sensor. General Electrical Failures. Circuit short to battery or open
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 combustion preheater module (CPM) has registered a signal from the overheat protection thermostat that is too high. The cause may be a short to supply voltage in the cable, a break, a damaged thermostat or poor contact. 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 supply voltage
- Break in the cable between the CPM and the overheat protection thermostat
- Damaged overheat protection thermostat
- Contact resistance, oxidation or loose connections
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 carries no voltage when the heater is off; if it does, the cable is shorted to positive
- 4Use a multimeter to check the cable is intact between the heater connector and the thermostat connector; a break means the cable must be replaced
- 5If the fault returns, have a workshop measure the thermostat resistance
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.