I have a P0420 problem, I replaced my O2 sensor but now I have to replace the cat. Could I just replace the cat with a resonator and will this pass emissions? Also will I need to reset the ECU and how can that be done? Any knowledge would be greatly appreciated, Thanks

 

Replace the cat, use a spark plug non-fouler to extend the O2 sensor out of direct exhaust flow (this sometimes works) or use an O2 sim.

 

To reset the ecu disconnect the negative terminal on the Battery for a couple minutes

 

Tpy, you don't need to start a 2nd thread on the same subject. Your other thread has been closed.