VOLVO
CEM-1A10 - Secondary battery Signal to low
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (4)
What does this fault code mean?
This fault only applies to cars with automatic engine start and stop. The CEM monitors the secondary battery voltage. If the voltage is too low or too high, the automatic start and stop function does not work.
Possible causes
- Contact resistance or oxidation in the terminals
- Damaged fuse for the voltage supply
- Open circuit on the voltage supply from the secondary battery, or on its ground cable
- Poorly charged battery or corroded connecting cables
- Damaged battery
- A battery charger with the wrong voltage has been used
What you can do
- 1Check that the battery is charged and that the battery terminals are clean and tight
- 2Check the fuse for the voltage supply from the secondary battery
- 3Has a battery charger been used recently? Check that it is meant for this car
- 4Clear the code and road test the car to see whether it returns
- 5If the fault remains, have a workshop check the secondary battery
Symptoms you may notice2
- Automatic engine start and stop does not work
- Idling with automatic engine start and stop does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.