I just got done with the ls1 lid mod and when I went to go start it up for the first time the service engine light wouldnt go off. So right now the car is sitting with the ground unplugged from the battery. What could cause this? I had a lt1 RA box on and it didnt have any problems. Could it be the computer needs to learn what going on? or could I have messed up a sensor?

 

There's no point in guessing so have it scanned.

Also, make sure your IAT and MAF are both plugged in.