The engine light came on and showed the check emission system message. I went to AutoZone to check the code. It showed P0420. They said it’s the Catalytic Converter and Exhaust Flange Gasket. I just had my emissions inspection about two weeks ago, and it passed. I filled up with gas yesterday. Is there anything that would cause this that would correct itself? I’m a single mom and want to check anything I can before I spend the money to take it to the shop.
The leaking exhaust gasket could be the cause of your problem. I recommend having that leak fixed first. Then, drive the vehicle for a few days to see if the light goes out on it own. If it doesn't, you may need to have further testing done. It's possible that you only need an O2 sensor, and not the catalytic converter, but the O2 sensors needs to be tested by a mechanic who knows how to test them.
Updated on February 15, 2019
By Eddie Carrara