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**Boog** · 02-24-2011, 12:12 PM

Scott there is probably a list of PO codes already posted here somewhere. It might be helpful to make a sticky out of that. Just a suggestion.

I know the PO430 is "catylitic activity below threshold". It means the cat ain't doin as much as it should. It can be a cat just gone bad and it can be something upstream has caused it to go bad. Burning overly rich, burning oil and burning antifreeze can all cause a cat to go bad.
The 02 sensor behind the cat monitors the cat's activity only.
How well does the truck run upon cold startup and when warm? Strong smell of gas when cold? Down on power when warm?

I don't remember what the PO420 code is for.
Scott?

02-24-2011, 12:12 PM	#3
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 12,947	Re: po420 and po430 Scott there is probably a list of PO codes already posted here somewhere. It might be helpful to make a sticky out of that. Just a suggestion. I know the PO430 is "catylitic activity below threshold". It means the cat ain't doin as much as it should. It can be a cat just gone bad and it can be something upstream has caused it to go bad. Burning overly rich, burning oil and burning antifreeze can all cause a cat to go bad. The 02 sensor behind the cat monitors the cat's activity only. How well does the truck run upon cold startup and when warm? Strong smell of gas when cold? Down on power when warm? I don't remember what the PO420 code is for. Scott? __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross