Circuit/System Description (Battery, Charging System And Starting System)

The ECM monitors the state of the charge indicator control circuit. The ECM should detect a low circuit voltage when the key is ON and the engine is OFF or when the charging system malfunctions. With the engine running, the ECM should detect a high circuit voltage. The ECM performs key ON and RUN tests to determine the status of the charge indicator control circuit.

During the key ON test, if the ECM detects a high circuit voltage, DTC P0621 will set. DTC P0621 will also set if, during the RUN test, the ECM detects a low circuit voltage. When the DTC sets, the IPC will illuminate the charge indicator or a warning message will be displayed in the driver information center (DIC) if equipped.