does any one know how to fixe P0420 code i just got the code after the front o2 sensor was melted and it says (po420 catalyst efficiency below threshold bank1) so i thought it was the front o2 sensor then i replaced the new front o2 sensor but the code come back when the car run passed 130 miles (i thought it sohuld be fine if the car run passed 50 miles and the ECU should recognized it but it 's not )Does anyone has the same experience? Any recommend ?, need help !!

thanks a lot

 

i believe thats the rear 02 not the front one

The rear is what would be for hte cat converter, I belive. That or your cat is bad.

 

i got cat delete and i also got the o2 fixed in the rear o2 sensor . Since i got my car and i never got the code before , it was pop up when i took off the front o2 sensor and it said bank 1 so i thought i should be the front one. It's that can be cause by exhaust leaking ?

any recommed? need help

 

hmm then in that case im not sure. It could be a damaged connector maybe for where the 02 sensor wiring clips into?

Not sure that is weird. Just delete the code with your tuning software

 

need help!

 

i got the same code but as posted before it was for the rear one.