Since I did my Th400 install from a M6 my service engine soon light has been on.Is there somthing I can do to get it off?Im guessing it has to do with some of the M6 harness stuff not being plugged in anymore

 

You are correct the check engine light and trouble codes can be programed out. Find someone with LS1 edit (shop edition) or similar programmer and they can take care of the light for you. Some sponsor on this site will eventually see this post. Post where you are located for them. I sent mine out for programming but I found and documented all of the related trouble codes first.