Quote: Originally Posted by
lipton1 
I have a 0420 code that just popped up, wht does catalytic 1/1 effeciency mean?
Ok well im going to take a wild guess and say you dont have a Cat on right now and that you prolly replaced it with a Needswings or with another aftermarket... and your still on a stock pcm...
Well if this is true then i dont think its really much to worry about... i never did... If you plan on atleast staging to 1 then it wont ever show up again... I think it means that its sensing that your cata has a higher flow then before and the effecincy is being lost thru a "leak" in the exhuast...(again if you have a dump then hell yea thats a huge leak)... but nothing to really worry about...
