i have a 2002 s s and my check engine light is on and i had the codes read and I'm getting the code p420 and the print out they gave me doesn't seam to be any of the problems with my car could it just be a bad 02 sensor??

 

Could be a bad 02 sensor, but most likely it's your stock catalytic converter is clogged.

See if they can replace it for free under an extended warranty just for the Cat, if not start exhausting other options, but DON'T let them charge you to replace with another cat because that WILL BE very expensive. There are cheaper and better alternatives if the case arises.

 

Yeah, it's either the cat or an O2 sensor. I've also heard of a p04xx code that is thrown because the gasket on your gas cap has gone bad - so it could be as simple as a gas cap.

 

extended warranty? How would I go about getting that?

 

Since the Cat has to do with your emissions, GM will cover that longer than your drivetrain.

Just ask your mechanic if you have a bad cat would they replace it for free, if they say yes then do it. If they say no, they'll want to charge you ~$700, so come back for better options lol

 

Okay I had a tune up done and both o2 sensors changed cleared the code and my mechanic said my cat has already been changed..so I drove it for a couple days and my cel came back on..could that cat be going bad????

 

When was the cat changed? And tell him to do a back pressure test on the cat to make sure

 

Idk when it was. Changed but I took it to a muffler shop and he looked at it said its a brand new one on there cause its not the stock one that the car comes. With??

 

its the P0440 code mine just came on yesterday..gettin it looked at tomorrow...its in the fuel evap system..

more or less the gas cap.

 

Well then if it's not the stock Cat and it was changed recently, then it's throwing the code because the stock cats SUCK, that's why my P0420 code was thrown, I put on a high-flow cat with my ZZP Downpipe.

Could have been replaced with a higher flowing Cat, and that will throw the code always. Nothing is wrong, but the code will be thrown because the car thinks since the flow is so much better than it was stock, something MUST be wrong.