i have a little problem if anyone can help serice engine light came on and i ran the codes it came up as po420 witch says (catalyst system efficiency below threshold) i think that means i running rich b ut what could be the problem

 

i actually just had the same code on mine. yeah, it says the same thing. well, along w/ saying bank 1. i was told its either the cat or the o2 sensor. i think i'm gonna go with the sensor first.

 

what did it cost you for the sensor and did you get it at the dealer

 

I remember on OBD-II the puter keeps track of the Oxygen sensors after the cats and reads the speed of the voltage swing to Identify the Health of the Cats. once the speed begins to match the voltage swing speed of the pre-cats oxygen sensors then the puter throws a code. If youre not runing rich or lean then its time for new cats..... well thats what it is suppose to mean by that code//

Marvin

 

I am pretty sure I am running rich but have no scan tools to prove it.

 

i was driving yesterday and the light went out hasnt came back on yet gotta love those sensitive computers