DTC Parameters

DTC P0621 will set if the generator L-terminal input voltage at the ECM is greater than 4.0 volts when:

• The conditions exists for longer than 0.5 seconds.
• The engine is NOT running.
• The ignition is ON.

DTC P0621 diagnostic runs continuously with the ignition ON and engine OFF. DTC P0621 is a type "D" DTC.