If its after the o2 sensor then I wouldnt think it would affect it. You can always repair it and see what happens.

 

So i swapped the Oxygen Sensor and then had both p0430 and p0420 code up. I was like WTF so i did this. I went out and got some spark plug non-foulers and screwed them on to both sensors, reset code and drove it 50 miles no check engine light and it passed emissions.

 

I have a 2008 mustang bullitt with a manifold back Magnaflow x pipe and its throwing a p0430 code on the bank 2 side. i replaced both sensors and checked the fuse in reguards to a mechanic saying that the sensors werent registering on the diagnostic. what else could be the issue?