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PCM or Wire Failure? EGR p0405
So I'm working on a 2001 Impala 3.4L. It had a p0405 code.
What I know so far:
Did some backprobe testing on the EGR connector. Pin E is reading 12v. Pin D is reading the 5v ref. Which is good, but on C (position signal to PCM) it would jump sporadically between .05 to .5v. Confirmed EGR is faulty. Plugged in a new EGR and now I'm getting a steady .79. Sweet, but here's the problem I noticed next...
Running the car the .79v doesn't change (except maybe +/- .01v) regardless of throttle. So... checked pin A and I'm getting 0.0v. What confuses me is that I can take this wire on pin A, ground it and that .79v still doesn't change. Which means I'm unable to manually command EGR. I'm concerned that this will simply throw a p0401 or some similar code when the computer goes to test emissions. Has anyone else had this issue? Does anyone have a wire diagram for this car? I would like to check for continuity to the computer but I don't know which pin it goes to. And I believe the wires feed into the side of the harness which would make it difficult (if not impossible) to figure out which wire goes to which pin. Does this sound like a bad computer?
Any advice would be much appreciated!