Theory Of Operation

The Powertrain Control Module (PCM) contains two internal 5-Volt Sensor Supply sources; Reference Voltage 1 and Reference Voltage 2. Each of these 5-Volt Supply sources are split internally into parallel circuits to provide a 5.0 volt reference to multiple three wire sensors. For self protection, if the 5-Volt Supply circuit is shorted to ground or if one of the sensors is internally shorted, the PCM will turn off the 5-Volt Supply circuit until the next ignition cycle.