Alternator & Regulator: Operation

The PCM maintains a system charging voltage of approximately 13-15 volts. PCM determines a control voltage or voltage goal based on inputs from battery temperature sensor (ambient temperature near battery) and system voltage at PCM. PCM compares control and system voltages whenever engine is running. If system voltage is less than control voltage, PCM will provide more ground to field circuit. If system voltage is greater than control voltage, PCM will provide less ground to field circuit.

If a problem is sensed in a monitored circuit, a Diagnostic Trouble Code (DTC) is stored in PCM memory and the Malfunction Indicator Light (MIL) will illuminate (with a few exceptions). DTCs can be read using the MIL, the Chrysler Collision Detection (CCD) Diagnostic Readout Box (DRB) or a generic scan tool.

NOTE: DTCs remain in PCM memory for approximately 50 ignition on/off cycles. DTC will be erased from memory if failure does not reoccur.

For certain DTCs, MIL will illuminate and PCM will enter limp-in mode. In limp-in mode, PCM attempts to compensate for particular component failure by substituting information from other sources. This allows vehicle operation until proper repairs are made.