p0420
 

For the longest time now i have had the p0420 code. Took to toyota many times and still no solution for it. Anybody else have this issue? anybody have any recommendations on what to check?

Did you search? Any mods on your exhaust/header?

A search for p0420 yields a ton of threads about headers and CELs.

-alex

i had this code way before i even had mods on my car. Just wondering if anybody with this car has had this code before stock?

bad 02 sensor?

or bad cat

checked the o2 sensors and not sure how to check the cat but if its is the cat then i need a whole new header im guessing...it cant be the 2nd cat because now i deleted it and im still getting 420 code

420 is not a bad code at all.
Why not get u ecutek license again and tell John to disable that code

if the sensor is fine i wouldnt worry b/c that jus means its the cat. so ur jus not as eco friendly, but if ur modding the car and changing even a catback then i doubt ur an econut anyways. other then the light being annoying its nothing. id b more worried about ur seatbelt light on if u werent wearing it lol

How did you check the sensor exactly? The secondary cat is not monitored so it wouldn't throw a P0420. If you're using stock exhaust manifold the dealer should cover it under warranty.

p0420 is a bad cat. you should get that checked out. might have a leak or something.

i had my mechanic check the plugs for me and he said they were fine...we checked for leaks and there was no leaks..when i took it to toyota they had checked everything out as well and could not determine the problem..when i clear the codes it takes a while for it to come back on so everytime they think they have fixed it ends up coming right back on. Im just going to tell them to change the plugs anyway and see if that clears the code.