2005 Ford Expedition check fuel cap warning… still a mystery after replacing and testing… found something strange under there

I’ve had this annoying check fuel cap message on my 2005 Expedition forever. Replaced the cap, checked hoses with a smoke test, no leaks. Today the check engine light came on with the same code… so I went under to check the hoses and found a white nozzle that doesn’t seem connected to anything. Is this normal?

Did you double-check the fuel cap? Sometimes they just don’t seal right.

Kiran said:
Did you double-check the fuel cap? Sometimes they just don’t seal right.

Yes, the cap’s brand new. My question is more about this white nozzle… it’s just hanging there unconnected. Shouldn’t it be capped or attached to something?

Could that be part of the vent system? I think it usually connects to the evap system.

Archer said:
Could that be part of the vent system? I think it usually connects to the evap system.

It’s right near the fuel tank cap. The black hose is connected, but this white one just sits there. Seems weird.

My guess? Someone may have tried to siphon fuel from the tank and put that hose in to get around Ford’s security feature on the filler neck. Maybe they left it there thinking they might need it again and just zip-tied it up.

Is there anything attached to the other end of that thin metal tube? And what did they use for the smoke test? If it’s the vent line, a smoke test would make it look like your gas tank was on fire.

On Chevy trucks and SUVs, the vent is in that same area, right behind the fuel filler. But they usually have a small filter on it to keep dust and debris out.

You could try plugging it off. The engine needs back pressure to run right, so it’s worth a shot.

Oakley said:
You could try plugging it off. The engine needs back pressure to run right, so it’s worth a shot.

Good idea! Any suggestions on how to plug it up or what to use?

Hadi said:

Oakley said:
You could try plugging it off. The engine needs back pressure to run right, so it’s worth a shot.

Good idea! Any suggestions on how to plug it up or what to use?

Maybe try a small screw? Just twist it right into the white plastic part.