VOLVO
CPM-U300362 - Battery Voltage. Algorithm Based Failures. Signal compare failure
System
Combustion Pre-heater Module (CPM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The fault code says the heater control module and the central electronic module have different system voltages. The fault is only worth investigating if it has been active for a long time in the same driving cycle, or if you notice the heater not working. In other cases the fault code can be erased. The heater cannot be started until the fault code has been erased.
Possible causes
- Contact resistance, oxidation or loose connections
- Damaged charging system
- Open circuit or short to ground in the supply to the auxiliary heater
- Blown fuse
- Poorly charged battery
What you can do
- 1Erase the fault code and drive the car for a while. If it does not return, no action is needed.
- 2With the ignition off, check that the fuse for the heater is intact. A half-blown fuse can cause faults that come and go.
- 3With the engine off, measure the battery voltage with a multimeter. Charge or replace the battery if the voltage is weak.
- 4Look for corrosion, looseness and oxidation at the connections to the heater and to the battery. Clean or tighten them.
- 5If the fault returns although the battery and connectors are in order, have a workshop check the charging system and the supply to the heater.
Symptoms you may notice2
- Poor heating in the cabin
- The parking heater does not work
What the fault can affect1
- The heater cannot be started until the fault code has been erased
General guidance for car owners. Diagnosis on the car can point to a different cause.