Theory Of Operation

There are two communication lines between the Powertrain Control Module (PCM) and the Generator(s). Based on sensed Battery voltage, the PCM commands the Generator (or 'Generator'/GEN-1 and 'Generator 2'/GEN-2 in a dual charging system) to charge the Battery (or Batteries: left side Battery and right side Battery in a dual Battery system) to a desired voltage. The maximum voltage the PCM will command the Generator(s) to charge is 14.75 volts. The PCM then receives feedback from the Generator(s) reporting the charged voltage level of the Battery(s). The PCM will not illuminate the Engine Malfunction Indicator Lamp (MIL) for this fault. But, the Battery lamp should illuminate when the charging system is not operating properly.