[219673]

hey i got the code P0420 yesterday. i have a grimmspeed gesi downpipe, and i know thats the issue, im just curious if its fine to drive with the code cleared for a couple weeks until it gets pro tuned which i hope will solve the problem

I really really hope you have some sort of tune on that car right now for the downpipe.

There is no solution for it. Cobb doesn't even support emission modifications and even if its tuned for ypull have the code.

 

[219673]

Interesting, I thought the whole reason to get the gesi j pipe was to prevent the code.

Hypothetically they meet emissions regulations while offering better exhaust performance. They work in places where they are part of the original engine management and engine design.

In practice they are not perfect although there are a few companies working to make them 100% EPA compliant now that the wording has been updated.