I was wondering how to identify an upgraded PCM. I bought a 2001 Grand prix GTP and i am finding new upgrades that i didn't know about and i wanted to know if the PCM is upgraded.

If it is upgraded by a company like DHP they will mark it with a sticker or other identification. If it was done by an individual the only way to tell would be to get it scanned using a scanner that will give you the programming. I think Autotap will do this but I am not certain. Otherwise there may probably no way to tell.

I agree with Lynn. DHP or Intense will put their logos/decals on the re-programmed PCM and revision number. You'll need to physically inspect the PCM if it is still mounted in the air box. My PCM sits in a tray under the Thrasher CAI so it is easy to get to.