P0420
 

Any idea on what might cause this code?
I have reset it and it comes back over again for the last week or so.
Is it the O2 Sensor or the Cat Converter?


thanks in advance. : )

code said bank 1, so its the oxygen sensor 1 right?
What should I do to fix this CEL? Keep reseting them won't work :(

Get a new catalyst, probably. They fail pretty often.

:-/

What are your symptoms?

Well there's the cel...

I have the same P0420 code as well the car was running fine then all of a sudden the car started running rich and the CEL came on there is a strong smell of gas fumes when you walk around the car and coming into the cabin when at a stop light. Everyone I have talked to about it including the dealer is telling me to change the cat on it, but who makes a decent cat that will last a bit longer?

One of your coils probably failed. A failed cat won't cause you to run rich, but running rich (due to improper burning, due to ignition failure) will cause a cat to fail.

Replace your ignition (coils, plugs, and wires) then either do a decat or get an OEM replacement from somewhere.

I had the same code come up after I installed a new cat and rear o2 sensor. I replaced the upstream o2 sensor and it solve the problem. Hope this helps.

I recently just got the same code when to get it check and now I'm freaking out since cats are like 1200 dollars could I use an after market one instead of a stock I hope some one can help

Just don't use one. It's free.

haha thought about it but i sadly have to pass the emission to get plates

I'm not sure how strict your laws are, I'm in Missouri.
My cat was dead at less than 20k because of misfires.
I replaced it with a BHR midpipe, and bought a Walker direct fit cat for less than $200 that I installed just for inspection, and took it off after.
I got a 2 year sticker, so it's not a big deal for me.