P0420 Code... Need help
 

4 weeks ago, got a shop that installed for me a mxp headers,overpipe and catback. Now this P0420 code appeared. I dont want to go the dealership coz for sure they will void my warranty.... Need help!

Did you get a tune? Every stage 2 flash turns that off, and any custom tune should do so as well, as long as the tuner remembers to do it.

If you didn't get a tune with a catless header then A. you'll pop a code, and 2) you're missing out on a lot of power.

Im scheduled on the 26th for a tune up.... Im glad to know it will fix it... For now i was able to clear the light by resetting it..


Thank you!

By "tune up" do you mean dyno/ECU tune? If so, then yes, that will fix it.

The light is a catalytic converter efficiency light. It measures both before and after the cat in the header. Since you've removed the cat from the header, the light will keep coming back until you get the car tuned.

Yes, ecu tune up..... So much knowledgeable members here...

Ty for your inputs sir!