80k miles. Evap system but this is a capless tank.

I won't be home to take a look at it for a week but want to hit the ground running when I do. In the mean time I will have my wife fill up and exercise the fill tube cover by putting the nozzle in and out several times. Grok tells me it could be a cracked hose or a gasket somewhere in the system. Wife doesn't smell any fuel that she can recall.

Are there any parts in this system more prone to failure than others that I should start with? Appreciate the insights.

More info, code started yesterday but she got gas today. Maybe it will cycle off? Either way I want to be prepared in the event that it doesn't.

Quick & Easy "Fix" for "Capless Fuel Systems" | BobIsTheOilGuy

Capless isn't really capless. There is a flapper door inside the filler neck that gets gummed up and doesn't close properly.

Yea that's why I recommended she push the nozzle in and out several times to try and free it up to work properly. That's my best guess but want to be prepared to move quickly on to the next thing if that's not it. We have a road trip coming up and I will have about two days to deal with this before we head out.

Use some type of cleaner too.
They mentioned it could be prone to freezing in cold weather also.

The next thing would be a stuck purge valve. I believe that is the issue with my 2020 Escape. Apparently a problem on Ecoboost engines of that age.

I get the light and it stumbles/dies immediately after fueling.

On my car the valve has about 4-5 lines attached that apparently you have to replace as a unit. Haven't got to that yet. Runs fine although the Check engine light is on.

Thanks I'll look in to that. She hasn't noted any issues with running improperly. From from SETX to Houston yesterday I assume it came in sometime during that trip or after.

Mine only does it on the first start after filling. By the time I get on the road, no issues.

I am going to fix it, just haven't made the time yet.

Does your fob still start it when the check engine light is on ? Mine doesn't and that's what ticks me off.

That's a good question. I will ask my wife.

Yes it still works.

That's good. I can clear the code and get one start with it then the code is back and it's useless again.

Ok so i have not got this warning to go away. I cleaned out the gas fill and that did nothing. Looking underneath around the charcoal canister I can slightly smell fuel but don't see any signs of leaking. Idk if that smell is just a byproduct of the purpose of it or not. Can't see or feel any damaged hoses or anything like that.

Don't see anything that sticks out around the gas fill underneath the car either.

Grok says it's most likely downstream of combustion process as the car is running fine.

Really need to get this fixed so we can sell this thing.

Ok so i have not got this warning to go away. I cleaned out the gas fill and that did nothing. Looking underneath around the charcoal canister I can slightly smell fuel but don't see any signs of leaking. Idk if that smell is just a byproduct of the purpose of it or not. Can't see or feel any damaged hoses or anything like that.

Don't see anything that sticks out around the gas fill underneath the car either.

Grok says it's most likely downstream of combustion process as the car is running fine.

Really need to get this fixed so we can sell this thing.

Well I cleared the codes with the neighbors scanner yesterday and it said that two were unable to be cleared but now the CE light is gone so I don't know what to think.

probably need a smoke machine to pinpoint where the leak is.

did you clean up the filler capless thing? or just look at it

I cleaned it up to what I thought was satisfactory but have no idea how to verify that.

Any clue how long it would take to throw the code again after clearing? We've taken the car out about 4 times since codes were cleared and it still isn't popping up. I never cleared them after starting this thread and then cleaning the fill tank as I assumed they clear themselves but maybe not? Maybe it was just a remnant of the fill cap issue and it's just been waiting for me to clear it?

Most codes will come back within 30 minutes of driving or so

Yea that's what I figured and it is still not back. I would have thought that once the issue was resolved the code clears but I guess you have to clear it. I bought a code reader so I'll chick it out tomorrow.

Check engine light is back. I'll check the codes when I get home b

Evap system still there but now it appears there's an issue with the electrical in the EVAP system.

This is what grok said

The image shows diagnostic trouble codes (DTCs) from a Powertrain Control Module (PCM) on your 2021 Ford Expedition XLT. Here's a breakdown of the codes and their potential issues:
P0455:00-EC - EVAP System Large Leak Detected
Meaning: This code indicates a significant leak in the evaporative emission control (EVAP) system, which manages fuel vapor emissions. The system isn't sealing properly, allowing vapors to escape.
Possible Causes:
Loose or damaged gas cap.
Cracked or disconnected EVAP hose.
Faulty EVAP canister or purge valve.
Leaking fuel tank or filler neck.
Next Steps: Start by checking the gas capensure it's tight and undamaged. Inspect EVAP system components like hoses, the canister, and purge valve for leaks or damage. A smoke test can help pinpoint the leak if it's not obvious.
P04F0:00-EC - EVAP System Purge Control Valve "A" Circuit Low
Meaning: This code points to an issue with the EVAP purge control valve circuit, specifically a low voltage condition, which suggests a potential electrical fault.
Possible Causes:
Faulty purge control valve.
Wiring issues (short, open, or poor connection) in the purge valve circuit.
Problem with the PCM itself (less likely).
Next Steps: Test the purge valve with a multimeter to check its resistance and functionality. Inspect the wiring and connectors for damage or corrosion. If the valve and wiring are fine, the PCM may need further diagnosis.
P0563:00-68 - System Voltage High
Meaning: This code indicates that the system voltage is higher than expected, typically above 16 volts, which can affect various electrical components.
Possible Causes:
Overcharging alternator or voltage regulator failure.
Faulty battery or battery connections.
Jump-starting or charging issues causing a voltage spike.
Next Steps: Use a multimeter to check the battery voltage with the engine runningit should be around 13.514.5 volts. If it's higher, the alternator or voltage regulator may be faulty. Inspect battery terminals for corrosion or looseness.
General Recommendations:
Start with the basics: Address the simplest issues first, like the gas cap for P0455 and battery connections for P0563.
EVAP Issues (P0455 & P04F0): Since both EVAP codes are related, they might share a root cause, like a faulty purge valve or a wiring issue affecting the EVAP system. Focus on the purge valve and its circuit first.
Voltage Issue (P0563): The high voltage could potentially cause other electrical issues, so prioritize checking the charging system to prevent further damage.
Clear Codes and Retest: After addressing each issue, clear the codes with a scan tool and see if they return. This helps confirm if the repair worked.
I don't have access to Ford-specific technical service bulletins (TSBs) or repair manuals for a 2021 Expedition, so I can't check for known issues or recall-related problems. If you'd like, I can search for more detailed information, such as TSBs or common Expedition-specific fixes for these codes. Would you like me to do that?

if that scanner has advanced functions you could check that the purge valve is functional. and as I said before try and find a smoke machine to test for any cracks or leaks in the system

i will see if there are any advanced features like that. it is brand new to me so i am not 100% on its capability although i did have to reuse it to reset the BMS because we were getting an alert after we replaced the battery.

I checked the codes twice last week and that voltage issue was not listed so i dont think that has anything to do where would i introduce the smoke to the system?

i contacted my local mechanic and offered to pay him for his time to help me diagnose it so we will see what he says to that.

hopefully getting my truck back from the shop today for evap problem as well. apparently had to replace the fuel pump control module. Could be similar to your troubles?

was yours under warranty or are you out of pocket? was yours throwing the same codes?

Sea Speed said:

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was yours under warranty or are you out of pocket? was yours throwing the same codes?

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out of warranty. 2020 gmc truck. code p0498

Ah ok.

Alright finally smoke tested it and didn't see any smoke coming out of anywhere.

Cleaned gas fill again and hit it with some lubricant before I smoke tested and there was no smoke coming out there either. Maybe that was it?

New code came up this time around though so that's no good.

Drove to Houston and back, about 3.5 hours total drive time and the check engine light didn't come back on. Hope it remains that way. Maybe I just had not cleaned the fill port enough.

were you able to check the purge valve function in the tool?

No I couldn't find that option on mine. It is normally open and when I smoke tested it I tested it without the purge capped first and it was open, then I plugged the purge line and tested the rest of the system.

Light is back this morning, not sure if reoccurring codes yet.

i suspect your purge valve might be stuck open or sticking open when it shouldn't be. if you haven't found any external leaks with smoke