I got a 2000 T/A. The way I bought it is has long headers to a straight through X pipe setup. My ECM never throws an O2 sensor code.(only secondary air once in a while). Does anyone have an idea how the last owner could have set this up? I have no problems with it and it runs fast as hell, I just don't want to get caught with my pants down if something goes wrong.
As for the last owner, I'll just say that I can't get in contact with him.

 

The codes and/or SES light can be turned off in the PCM. If the PCM is told to ignore the lack of a signal coming from the rear O2 sensors...it'll do just that.