Generator & Regulator: Operation

The Powertrain Control Module (PCM), maintains a system charging voltage of approximately 13-15 volts. PCM determines a target voltage based on inputs from battery temperature sensor (ambient temperature near battery). PCM compares target and battery voltages whenever engine is running. If battery voltage is less than target voltage, PCM will provide more field current. If battery voltage is greater than target voltage, PCM will provide less field current.