P0420 OBD Code

[msymms]

Hi All,
My 2011 Versa is throwing the P0420 Code. I have done some research and I realize that this may be O2 sensor related. So, has anyone had this issue and resolved it? Should I try the O2 sensors first before the Cat? Can this be DIY? I want to avoid the trial and error system of car repair. I did that enough in high school.

TIA
-mark

[jasonkg]

Bringing this one back from the dead in hopes of helping someone else in the future. Wish I would have saw this post sooner...

I had the same code and performed a series of trial by error repairs... I replaced both O2 sensors first, that did not fix the problem. Then I bit the bullet and replaced the Cat which ultimately fix the issue. Since O2 sensors are replacement parts I didn't mind replacing them since their bound to go out eventually. I had about 90000 miles on my car when this occurred about 1.5 yrs ago. Hope this helps anyone else that gets this code in the future.