PCM Controlled Generator

The PCM controls generator charging by supplying 5 volts on the generator L-terminal circuit whenever the ignition is turned On or the engine is running. This control voltage is necessary for the generator to charge once the generator begins to spin. With the ignition On, engine Off, the generator will ground the generator L-terminal circuit through a resistor. When the engine is started and the generator begins to charge, the generator will open the circuit (still using the 5 volt control voltage) signaling to the PCM that the generator is charging.

CHARGE TELLTALE - If the voltage at the PCM generator L terminal is low or if the circuit is grounded when the engine is running, the PCM will send a message to the I/P cluster over the Class II link to turn On the Charge telltale.