VOLVO
ECM-U300300 - Battery Voltage. General Failure Information. No sub type information
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS80 (2007–), V70 (2008–)
Show models by year and engine (2)
What does this fault code mean?
The ECM monitors the battery voltage and checks it against the reference that the central electronic module (CEM) broadcasts on CAN. The code is set when the voltage the ECM measures is lower than the value sent over CAN. The fault may be caused by contact resistance, oxidation or a poor connection in the connections.
Possible causes
- Contact resistance, oxidation or poor contact in the connections
What you can do
- 1Check that the fuses are intact.
- 2Check the battery and its connections, and the connections to the engine control module. Look for oxidation, play and loose connectors.
- 3If the code returns, have a workshop read out and troubleshoot the voltage with diagnostic equipment, as this requires measurement.
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.