Good day folks,

I have a 2020 STX w/ 2.7L and lately it as been spitting out two codes very randomly, sometimes it can take 2-3 weeks before it comes back after clearing. It has 150,000Kms.

Does anyone know what might be causing this? I refuse to believe that both my cats are already done. I used to own a 2010 w/ 5.4L and I sold that truck to the scrap yard with 480,000kms and never had a cat code once.

I'm thinking that Ford program thresholds are too low and it triggers the code once in awhile.

I have monitored the cats temperatures on Torque during a 2 hours drive and they match perfectly and so do the O2 sensor outputs, therefore I don't believe my cats are blocked from crap.

Finally, there is no oil consumption, no sweet smelling smoke or blue smoke and my coolant level isn't decreasing so the engine isn't burning anything it shouldn't.

Bottom-line is that I don't want to throw new cats on and have the issue come back since it's a programming issue, if it's a programming issue.

Maybe some US folks on here heard of a TSB that addresses this issue since up here in Canada, we don't have those.

Thanks again everyone!

Cheers!

EDIT: I did run a bottle of "Extreme Catalytic Converter cleaner" a month ago and didn't see any real change.

 

Found a TSB that explains how to de-sulfate the cats, did anyone try it and if you did did it solve the issue?

I attached the TSB writeup to this post.

 

Yes, it solved the issue for me, at least so far. The first week of 2024 I bought a 2021 with 19k miles. 3 days after bringing it home I got a check engine light with codes PO420 and PO430. I initially scheduled an appointment at the dealer but it was almost 2 weeks out. During the wait I did some research and found the same TSB you did. A few days later I took the truck out, drove it around for 20 minutes to warm it up, and then found some isolated back roads and did some WOT pulls from 20-70mph, and a fair amount of high rpm driving in manual mode. The check engine light went out after about 15 minutes of this. This was 3.5 weeks ago, and I've put 1200 miles on it since then and it hasn't come back on. MPG seems to have gone up about 10% too since I did this. I assume the cats were partially plugged with soot.

 

Update!

A few weeks later, PO420 came back. Took it to dealer, but light went out on the way there. Dealer checked it over, took it for a test drive (I suspect they were full throttle most of the time, as they went 30 miles and used just over 1/8 tank of gas). Handed me back the truck, told me that the cat passed all checks and was good. About 10 days after this, the code came back again. Dealer is ordering me a new cat. PO430 has not come back though, just PO420 and that is the cat they're replacing.