"Check Fuel Cap" LED just showed up on my dash.

[2004mountaineers]

"Check Fuel Cap" LED just showed up on my dash.
What is that about ? The fuel-cap I have had for only
since June 2023. It's almost brand-new.
Any ideas of the cause ?
(No symptoms, just a dash light.)

FWIW, this is the fuel cap:

https://www.amazon.com/dp/B000CHMLK8?tag=seriouexplor-20

2004 Mercury Mountaineer, awd, 4liter v6.

 

[olddaddy75]

I think you have the wrong fuel cap. The one in the link will not fit my 03 ex properly, and I think your mounty takes the same cap as mine. If it is the correct one, try to put some petroleum jelly on the gasket, making sure there is a good seal when closed. Other causes are a leak in the systen that goes to the charcoal cannister.

 

[2004mountaineers]

I think you have the wrong fuel cap. The one in the link will not fit my 03 ex properly, and I think your mounty takes the same cap as mine. If it is the correct one, try to put some petroleum jelly on the gasket, making sure there is a good seal when closed. Other causes are a leak in the systen that goes to the charcoal cannister.

I will try the jelly. If Amazon and Walmart are right, the part is correct; but they could be wrong.

 

[olddaddy75]

I clicked on that cap on amazon, and it stated DOES NOT FIT 2003 EXPLORER. You do NOT need a locking gas cap, there is a screen near the end of the fill pipe that prevents ANYTHING rigid from entering the fuel tank. Try the old cap, if it worked. I tried in vain to siphon fuel from these tanks, and it is not possible. I think your mounty and my explorer are the same in that area. Other possible causes of the fuel cap warning are the entire vent system that prevents gas fumes from entering the atmosphere.

 

[2004mountaineers]

I clicked on that cap on amazon, and it stated DOES NOT FIT 2003 EXPLORER. You do NOT need a locking gas cap, there is a screen near the end of the fill pipe that prevents ANYTHING rigid from entering the fuel tank. Try the old cap, if it worked. I tried in vain to siphon fuel from these tanks, and it is not possible. I think your mounty and my explorer are the same in that area. Other possible causes of the fuel cap warning are the entire vent system that prevents gas fumes from entering the atmosphere.

Yeah, I don't know why amazon and walmart say that it fits a 2004 Mercury Mountaineer.

 

[olddaddy75]

They can sell more that way LOL