diagnostic codes

well the o2 sensor took me forever to find, mainly because I thought it was connected to the exhaust pipe <_< I checked the sensor and the plug that the wires connect to and found that one of the wires is broken. Maybe this is the cause? Another question I have is about the egr block-off plate. What are they and do I have to remove it to pass emissions. (Georgia, U.S.A.) The car has a custom dp, a test pipe, and a custom exhaust. If I replace the test pipe with the stock cat should I be able to pass emmisions?

Thanks a bunch suprra_girl

oh, and I didn't have the a/c ... what exactly is the tps? sorry for all the questions