Hey my CEL just popped on shooting out a code p0420!!!! I have already tried the search options, with little help... has anyone had this pop up and what did they do to fix the problem so the code doesn't come back?

Please tell me a turbo back exhaust will fix this!!!!!

Thanks,
Paul

 

Check your catalytic converter.

 

Ya I got that part through the searches but has anyone else had this problem

 

P0420 is a catalyst efficency code. Could be your converter going bad, or it could indicate an issue with the downstream o2 sensor. Or in some cases just a fluke/improper reading. Clear it and see if it returns.

Are you running a test pipe or High flow cat?

 

so you have a stock exhaust is what i gather. try removing the rear 02 sensor and putting in two anti foulers. you will have to drill one of them out to get the 02 sensor to fit but its simple to do. many people do this when they run a test pipe or high flow cat. not sure why this is happening with a stock exhaust. here is the detailed write up

https://www.evolutionm.net/forums/ev...cel-light.html