VOLVO
CEM-U300317 - Battery Voltage. General Electrical Failures. Circuit voltage above threshold
System
Central Electronic Module (CEM)
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 central electronic module (CEM) monitors the battery voltage and has found it too high for a while with the engine running. The cause may be a damaged generator or a damaged battery. The fault is stored with the engine running, once the high voltage has lasted long enough.
Possible causes
- Damaged generator (GEN)
- Damaged battery
What you can do
- 1Check the battery: if it is swollen, leaking or will not hold its charge, it should be replaced
- 2If you have a diagnostic tool, read battery voltage in live data with the engine running and check that it is steady and does not climb over time
- 3Have a workshop check the generator and the charge regulator, since a faulty generator can supply too high a voltage
- 4If the fault returns after the battery has been checked, have a workshop check the charging system
Symptoms you may notice5
- The battery discharges
- The generator warning lamp comes on with the engine running
- A red warning symbol and a text message appear
- The battery seems to be dead
- The engine does not start
General guidance for car owners. Diagnosis on the car can point to a different cause.