P2138 Chevrolet - Should the output voltage between the two sensors match?

Question

I have one sensor that reads .5VDC (pedal not pressed) to 2VDC (pedal floored).
The other sensor is 1VDC (pedal not pressed) to 4VDC (pedal floored)
Should they be the same or are they directly proportional?

Answer 1

P2138 Accelerator pedal position (APP) sensor 1-2 correlation

The APP sensor 1 signal voltage at rest should be near the low referrence and increase as the pedal is depressed  and should be a 0.33 at idle to 4.59 WOT. The APP sensor 2 at rest position is also near the low refference and increase as the pedal is depressed. APP should be near 0.16 at idle and 2.30 volts at WOT. Test your 5 volt reference , if the refrence is is less than 4.8 volt you will need to replace the ECM. If it also is greater than 5.2 volts you will need to replace the ECM. For now look into a TSB bulletin number 07-06-04-019D.this is about a intermeiitent P2138 being cause by water intrusion entering into the harness in the instrument panel and causing poor connection.