P0420 Ford -

Question

I have a 2004 Ford F 150 with the 5.4 liter engine it through the P 0420 code after we put a new exhaust on it. They had drove it without an exhaust with it just cut right behind the catalytic converters. So with it being that way could it have ruined the catalytic converters or what is going on here thanks.

Answer 1

its possible the exhaust "leak" caused the light to come on. Try to reset the code and see if it comes back