Generator F Terminal

The F-terminal circuit connects the generator to the PCM. The PCM uses this circuit to monitor the Pulse Width Modulation (PWM) of the field circuit. When the key is in the RUN position and the engine is OFF, the PCM should detect a duty cycle near 0 percent. However, when the engine is running, the duty cycle should be between 5 and 100 percent. The PCM monitors the F-terminal circuit for conditions outside the normal operating range. If the PCM detects an incorrect condition, DTC P0622 will set.