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Paul, first off I can’t thank you enough for your classes. I ran across the p042 code on aGMC and remembering the rule on a 3 wire pressure sensor. Question is this, when I unplug the sensor harness and test the circuit, I have 5V ref, signal wire also has 5V. I noticed the scan data went from 0 Volts plugged in to 2V unplugged. Is the 2Volts unplugged on the the scan data what the ECM is reading half of the 5V circuit?
