Well, if it'* built into the PCM, wouldn't make sense cause the new PCM had the same issues. I'm gonna take her to a dealer next Tuesday when I'm off.

its not necessarily the pcm that has the failure, shorted wiring on the qdm output is a common cause

Where should I search and how would I diagnose? Do know that water got into the car in the back half...and it was quite a bit. Shortly after my original PCM failed (stopped talking to ICM) and now I have Mike'* in my car.

95% of that wiring would be in the engine harness, so you have figure out why the scanner and pcm arent talking.

On-board diagnostics - Wikipedia, the free encyclopedia
scroll down to obd 1.5, and see if you have +12 on 16, continuity to ground on 4 and 5 and pin 9 is data cant really check that but if you have power and ground you might have to take that engine diagram and test from the data pin on the port to the data wire at the pcm, check for continuity. and for loose or corroded pins. if you can hook up the scanner and get the code it will narrow your trouble shooting significantly.

Check both of your ground buss'* if you already havent. I'm not completely sure what'* all tied into the passenger side buss, but the drivers side has power windows/locks/fuel pump and tail lights. Who knows whats on the passenger side.

https://www.gmforum.com/electrical-1...1999-a-303224/

I don't know why some of the images are not coming up. But, just pull the plastic trim piece next to the front doors off the floor and you will see a bundle of wires towards the front kick panels.

Already did the ground busses, they were 85% perfect and I cleaned them up with a light wire brush on my dremel.

Continuity check from the OBD connector to the PCM connectors.

the pic i posted went away when you moved it.

What pic?

It shouldn't of. I copied everything over like normal. The other images stayed Hmmm. must go fix it.