VOLVO
CPM-3341 - Overheat protection thermostat. Signal too high / Signal missing
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 combustion preheater module (CPM) has registered a signal from the overheat protection thermostat that is too high. The thermostat protects the heater from overheating, and the fault can be caused by a short to supply voltage in the cable, a damaged thermostat or poor contact. The heater cannot be activated until the 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
- 2If you have a diagnostic tool, activate the heater and check that the temperature at the overheat protection thermostat rises
- 3Disconnect the connector at the overheat protection thermostat and check that the contacts are secure and free from oxidation
- 4Use a multimeter to check that the cable carries no voltage when the heater is off; if it does, the cable is shorted to positive
- 5If the fault returns, have a workshop measure the thermostat resistance and check 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.