VOLVO
CEM-U300316 - Battery Voltage. General Electrical Failures. Circuit voltage below 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 low for a while with the engine running. The cause may be a battery that is not charging enough, corroded connections or a generator that is not charging. The fault is stored with the engine running, once the low voltage has lasted long enough.
Possible causes
- Poorly charged battery or corroded connecting cables
- Damaged generator (GEN)
- Damaged battery
What you can do
- 1Check that the battery terminals and earth connections are tight and free from corrosion
- 2Check that the battery is in good condition; a battery that will not hold its charge may need replacing
- 3If you have a diagnostic tool, read battery voltage in live data with the engine running and check that it stays steady
- 4If the generator warning lamp is on or the voltage drops when the engine runs, have a workshop check the generator
Symptoms you may notice5
- The battery discharges
- The generator warning lamp comes on with the engine running
- The engine is hard to start or cranks slowly
- A text message appears in the display
- The engine does not start
General guidance for car owners. Diagnosis on the car can point to a different cause.