DTC P0622: Generator "F" Terminal Circuit: Description

"L" terminal is a 2-way link between PCM and generator. PCM supplies generator with 5 volts whenever ignition is on. PCM will not supply 5 volts to generator during engine cranking if battery voltage is less than 9.6 volts. Once engine is running, generator must have 5-volt supply voltage to charge. If generator stops charging while engine is running, it will ground 5-volt supply from PCM. When PCM detects this ground, it will send a message to instrument panel cluster over Class II link to illuminate charge light. PCM determines electrical system load by monitoring generator Pulse Width Modulation (PWM) output on "F" terminal (Gray wire).