I don't know if this helps, but on my 2000 Trooper the PCM is a GM PCM. The codes are GM codes. I have a scantool called EFIlive for my Camaro and it will pull the codes and tell me what they are for the Trooper also. It will also give me realtime data. Do you have the drive by wire Throttle body? Those are similar to the ones I had when I forgot to plug mine back in.

2000 Trooper 4x4, Auto, TOD pretty much stock at the moment.

2001 Camaro Z28, M6, fully loaded and too many mods to list! AKA Dark Angel