error Code P0420

[hammond]

Anyone have experience with this?

as I can read, it is the catalyst, or the catalyst sensor...

 

[samotahoe]

you need to test your 02 sensors. are there any other codes accompanying that one? i would get a scanner and check your fuel trim to see if you are running lean or rich. 90% of the time you just need 02 sensor and some cases a new cat. but you need to find out if its bank 1 or bank 2.