Hey guys,
My dad went in for emissions the other day, and they failed him cause the computer was throwing out PO420 error code. they said to replace the oxygen sensor and the cat. Does anybody out there have a description for this error code? Thanks for any info

 

Here's the OBDII code list: http://www.obdii.com/codes.html

An 0420 is catalyst efficiency below threshold. How many miles are on the truck? If you do end up replacing the cat I would just get an aftermarket highflow one, since one from the dealer will be ridiculously expensive.

 

The Truck has about 110k on it right now....

This may be a really dumb question, but what the heck is a catalyst system, and being that it has to do with bank1 only, would that be an indication of something more serious than a cat?
just curious, thanks again for the help

 

The catalyst helps remove emissions products (NOx, CO, HC) from the exhaust so that the vehicle doesn't pollute as much. I wouldn't worry about the code indicating anything more than the O2 sensor or catalytic converter (although neither one is cheap). When I've removed my cat it's caused a 420 code so your best bet is probably a high flow cat. There was a discussion on here a couple months ago about highflow cats and it had some links in it for buying them, you could probably find it pretty easily.