about a month ago i got some codes pulled and they were all dealing with my o2 sensor/ emissions from my down pipe......i replaced both sensors and even put non foulers on the after cat sensor so it wouldnt show emissions...go the codes pulled again after and it still says something like no activity detected on sensor 2....does anyone have any idea to why there is no activity...connection looks fine, so i dont know what could be wrong.

 

any ideas?