OBD2 error code: P0420 Freeze Frame sub code: fuelsys1 CL

[franbasi]

I got a "check engine" light 50 miles after filling my almost empty gas tank with cheap gas.
some advisors on the web say "look no further, you need a replacement catalytic converter"
others say it could be a problem with the capless gas tank filler. And there are those that say it "could" be the cheap gas.
Is there anyone with experience in this area?
Ford Fiesta 2012 SEL fuel injection

 

[SyntheticAtmosphere]

One tank of cheap gas isnt going to severely damage your converter. Perhaps if you had been using unleaded. But chances are the converter was tired.
First I would look at the whole of the exhaust system for leaking connections, bad gaskets or pin holes. Be diligent, a small leak can affect the sensors and throw a P0420.
The sensors also need to be scrutinized. It would be unfortunate to have an o2 sensor misreading. Check sensor age, condition, wiring etc. A good mechanic can diagnose the sensors to see if they are operating within allowable requirements.
I have had improper venting of the charcoal canister/fuel tank purge trigger P0420. It would be valuable to have a good mechanic take a look if you dont have the tools and knowledge.
Fuel pressure out of spec high or low can also over time cause issues with the catalytic converter.

What constitutes cheap gas?

 

[Handy Andy]

"Cheap Gas"?

Did you use E85? Then just (somehow) drain the tank asap and refill with fresh 87 (+ or above) octane.

Then run the system until the tank is empty - see if this clears up.

Lots of times the sensors are sending data about the converter - but are using the values present if the programming of the DTC codes were pre-determined - as example like; "If you ran the right fuel - this symptom results in this" - condition. The system looks up the "Best guess" and thows that code at you.

Does not mean it is the correct guess, but that it fits the facts present - which if you had run regular fuel - the the condition is true, does not mean that it's destroying the system, just that it means "Hey! What'cha trying to do to me here?"

Try to correct the condition using proper fuel asap - and see if it recovers.