WhiTeSS01

Just curious as to if anyone has had this code and figured out what it directed to. Maybe I can save some time. P0420 Catalyst system efficiency below threshold. I am looking toward the o2 sensors. car is a 01 ss no mods except k&n.

thanks
Matt

FatZ28

iTrader: (1)

Either your cats have gone bad or one of your rear 02's is shot.

WhiTeSS01

I searched through the threads and saw that this is actually covered by gm. 8year 80,000mi warranty on emission parts. Called local chev dealer that said that is correct but I have to pay the diagnostic fee to determine it first. If it is then they waive the charge of replacing it. diagnostic fee is like $88

WS6FirebirdTA00

iTrader: (33)

if its the cats go for it, if its the o2s u can get one cheaper than that. but its most likely the cats, might wanna get the fuels system cleaned out too that can help