Thread: P0420. Cat or 02

Car just went over 80k. I really don't want to replace the wrong one as their both expensive what would be our guys advice?

Your cat is GM warrantied to 120K miles, or is it 80? .. I forget.

The code is the pcm saying the delta from front to back sensors isn't enough. Which typically means the middle aka cat isn't working up to potential.

Call GM and ask about the warranty on the cat. Most likely they'll install a new one for free

80k damn!!