VOLVO
CPM-3702 - Control module. Supply voltage 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 logged a supply voltage that stayed too low for some time, and this sets the code. The cause may be a poorly charged battery, poor contact at the module connections or a blown fuse. The heater cannot be activated until the code has been cleared.
Possible causes
- Poorly charged battery
- Contact resistance in the module connections
- Blown fuse
What you can do
- 1Check the battery: charge it if needed and check that the terminals are tight and clean
- 2Replace the fuse feeding the CPM with a new one if it has blown
- 3Check that the connectors at the CPM are secure and free from oxidation
- 4If you have a diagnostic tool, read battery voltage in live data as the heater starts and see whether it drops sharply
- 5Clear the code and start the heater again; if nothing is found, it may have been a temporary fault
Symptoms you may notice3
- Poor heating in the passenger compartment
- The parking heater does not work
- An information lamp is lit
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.