Newbie help on codes

[drd217]

I ordered a code reader on line and it came up with P0420 and P0442. After doing research online I see P0442 is a leak. Could this be causing the P0420 code, which apparently means a new cat?

I'd probably have to take my car to a shop to do this kind of work, so should I get them to check for the leak first and see if that corrects the problem before replacing the cat?

I have a 2004 base Vibe with 211,000 miles on it. It's been a great car, and I've never changed the cat or oxygen sensor (if it ain't broke don't fix it methodology).

Thanks for any help

[trb]

Looks like the P0442 code is the evaporative emissions control, most of the time the gas cap. It says the fuel system is not properly sealed, and the most common cause for this code is not completely turning the gas cap until it clicks. My daughter did that, and the light came on. When Autozone read the codes, the guy walked to the gas door and sure enough, the gas cap was not secure. If yours is tight, then the seals could be bad on it or you could have a small leak someplace in the evaporative emissions control system that is letting gas vapors escape the gas tank. It's probably not leaking raw fuel, but just letting vapors vent instead of containing them in the canister that is designed for this. Now I doubt this is related to the converter code, but I would check it out anyway before spending a lot on a new cat.