Low battery charge
Loose or missing alternator drive belt
Open or short system voltage circuit
Engine Light ON (or Service Engine Soon Warning Light)
Slow engine start
Low battery power
The battery supplies electricity to the Engine Control Module (ECM) even when the ignition switch is OFF. This electricity allows the ECM to store data such as Diagnostic Trouble Code (DTC) history, freeze frame data, fuel trim values and other data. If the battery voltage falls below a minimum level, the ECM will conclude that there is a fault in the power supply circuit. The next time the engine starts, the ECM will turn on the Malfunction Indicator Light (MIL) and a DTC will be set.