Need help, fuel concerns 2020 GT

[Creamsicle5.0]

Forscan will cycle the vent valve and the purge valve. I wonder if your charloal canister is filled with liquid fuel?

I’m pulling the canister off tonight hopefully to check for air flow and fluid. I’m wondering if there’s a way to check purge valve mechanically without Forscan by chance?

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[Creamsicle5.0]

I’m pulling the canister off tonight hopefully to check for air flow and fluid. I’m wondering if there’s a way to check purge valve mechanically without Forscan by chance?

(UPDATE)
Good news!! I figured it out (I believe)
I had a faulty PCM Relay in the fuse box. When I pulled all relays and bench tested them, they all worked fine. I swapped most around, the other night as well and didn’t notice anything different. Tonight I decided to buy a replacement relay (just in case), plugged it into the PCM relay slot and she fired alive! Took it for a 20~ mile trip, and it’s running great. Entirely unsure how i didn’t find the relay before after bench testing them all and swapping them around but i won’t complain!

 

[KingKona]

.....my car also has long tube headers and cold air so warranty would be voided.

No, it absolutely wouldn't be voided.

Seriously, we need to quash this bad information.

 

[Garfy]

Cheap code readers will read the codes just fine BUT
If you plan on working on your own cars a bidirectional scan tool is worth the money. They can run from a couple hundred dollars to several thousand. Good ones for a serious diy guy are $600 - $1k. The things they allow you to test and do make them worth the investment. Look into Autel for examples of what they can do.

What is your definition of a healthy battery voltage?
FWI, a fully charged battery is the first step when diagnosing anything on a modern car.

Definitely get that bidirectional scanner. You can turn things on/off, etc. like your fuel pump to see if it's actually being activated. With the other electrical warnings, it kind of seems like an electrical problem. Especially since he drove 40-50 miles which would consume up to 2 gallons of fuel; seriously doubt that extra tap after the nozzle clicked off would put 2 gallons of added gas in the tank.

 

[ORRadtech]

With the other electrical warnings, it kind of seems like an electrical problem. Especially since he drove 40-50 miles which would consume up to 2 gallons of fuel; seriously doubt that extra tap after the nozzle clicked off would put 2 gallons of added gas in the tank.

It doesn't have to be much extra fuel to get fuel into the charcoal canister. Repeatedly topping off the tank can cause a multitude of emissions problems.
I am not sure how the protocol is set up on the Mustang but evap codes can set other random fault codes in an effort to make sure the evap code is fixed. For example on some cars a p0420 code (failing cat converter) can set traction codes and set codes that can stop the ac from working.
An example

 

[D Bergstrom]

Yes, when I fill up I always wait a few seconds after the pump clicks and click it one more time.

I have done the same thing for the last 6 years between my 2017 mustang and my current 2020. Have also done it for the last 5 years on my 2018 F-150 and the last two years on my wife's Nissan Rogue. (All of them have the same cap less fill system.) Have never had an issue with any of them. Now if you have fuel dumping out of the tank after removing the nozzle, that could be an issue, but one more click after the first click shouldn't cause a problem, it's not overfilling it.

Glad you got it fixed! Kind of concerning a relay went out that soon on a 2020, makes me wonder about my 2020.

Doug

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