Couple things....


KOEO .489VDC on the grey reference wire: Red DVOM probe to the grey wire and black DVOM probe to a good ground? 4.89VDC would be very close to what you're looking for, Are you sure of the placement of the decimal?


The grey wire at pin 27 is Vref from the PCM going to the sensors. If you test voltage on the wire that you cut, where it exits the PCM, it must show Vref, (~5.0VDC) with KOEO.

 

Yup. .489v not a misplaced decimal.

Even the DTCs confirm that.

Which is why I was wondering if whoever rebuilt the PCM used the wrong resistor (e.g 100ohm vs 10ohm) bringing it down one decimal place too far.

I will dive in to it on Sunday, as I'm off work.

Cheers

 

Sorry to be on a bit of a hiatus... Life happened.

Anyway...

I went and tinkered with the blazer the other day. Just for fun I took measured the voltage at the EGR. And I was astounded to see that it was displaying 4.88v There was no excitement. Just kinda threw a curve ball in there as it was the first time I was seeing what I was supposed to.

I could rock the truck and see the voltage change on my meter. I thought that was crazy. Eventually found out that it was a short to ground on the Pin 12 side. Did a few overlays, and bingo! Good as new! Drives great. Still a couple codes but they can wait. Im going to sit and enjoy my somewhat amount of success.

Yay? lol