Trying to diagnos a problem that has me a bit confused. Thinking it might be a PCM problem, but here goes. Car started Mil light six months after rebuild. The strange part of it is, smog shop changed one sensor, drivers side. Checked ohmage myself from terminals at PCM to sensor plug-in on harness. Ohms were .5 on passenger side and 1.7 on drivers side. When clearing trouble code, car starts and Mil is out. I can drive the car with little if any noticeable decrease in performance and no Mil light. As soon as I shut car off and restart, the light comes on. What the heck is that? Is the code only set on second restart? Any ideas would be gggggrrrrreeeeaaaattttly appreciated.

 

First, it almost for sure isn't the PCM. Get to it the very last thing you consider, just before scrapping the car!!

All codes have criteria (many set by law) - see the codes PDF (in FAQs / JTIS).

You'll need to follow the new member stuff you've not so far done (post an intro in the right place etc) but welcome in advance LOL

I'd get an OBD tool which does live data so you can read what the PCM actually sees. USB elm327 is great but some of the cheap clones don't work on the early (pre 2003) cars

You really really want the codes PDF as it has a lot of other good data.