i have a 20 f350 stake body that has p0420 code took it to dealer. they said it needs new catalytic converter 4000.00$. only 63000 miles. dealer said no warranty coverage. warranty only goes to 36000 on f350 converters. anybody have any solutions ?

 

I would check the coils for corrosion, and the plugs for wear.

 

would that cause a code p0420,

 

Id bet your downstream O2 sensor is faulty. Do you have the means to test the sensor yourself, or are you solely reliant on a mechanic?

 

What is your GVWR? I can't get into the final link at ford.com/support.

5/50 and 7/70 on expensive emissions components is mentioned, but commercial use and high gvwr are killers for the warranties.

Looks like some things to run down if it's just that code and you haven't been running it with the code for a year:

https://www.autocodes.com/p0420_ford.html

If you do a search by the code, you will get a bunch of hits for Ford.

 

i paid $1300 for converters for my 2014 from tasca ford 2 years ago. than another $120 for 02 sensors.

 

The price of replacing converters has gone up since a couple of years ago. I had to replace one a few months ago, and it set me back $440 at the local muffler shop. The quality of the converter is nothing like one from Ford but I highly recommend to get an aftermarket one from a muffler shop. It last a long time and it's much cheaper. That code does not necessarily mean however that the converter is bad. A good mechanic can test the converter and tell you if it is good or bad. It may be just a bad O2 sensor

 

Was the truck presenting any symptoms? Or did you just take it to have the code checked out?