Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Gas cap IDIOT light, 2006 Ford Explorer

Gas cap light recently came on.

After I recently gassed up.

I find nothing wrong with the cap.

It’s screwed in. Door closes fine.


Most likely you have a leak somewhere in the fuel tank or tank vent system. The light comes on when the tank and vent system fail a pressure leak test. The fuel door has nothing to do with it.

Are you saying that you have a light that is dedicated to telling you that your gas cap is off? Or do you mean the more generic check engine light?

Remove the gas cap. Take some petroleum jelly and coat the seal on the gas cap and put it back on so it clicks three times. If the gas cap light comes back on, try replacing the gas cap.


I have never seen a car with a gas cap light. I have seen many cars with a CEL (Check Engine Light). A loose or defective gas cap is only one of many possible problems that will cause a CEL.

When that light comes on, it means the computer has noticed that something is not right. As long as it is not flashing, it is not critical (Flashing means it is critical and continuing to drive may result in expensive damage.)

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

Agree with all other comments.
Take vehicle to participating auto parts store.
Let them do scan of check engine light.
Bring code (ex: P0310) here for advice.

I have seen some Fords that do have a specific “gas cap” light. I don’t know if the OP’s is one of them, but I assumed it was.
Here’s a passage from one such owner’s manual.

“Check fuel cap (if equipped):
Illuminates when the fuel cap may
not be properly installed. Continued
driving with this light on may cause
the Check engine warning light to
come on. Refer to Fuel filler cap in the Maintenance and
Specifications chapter.
Instrument Cluster

Why do people assume that something must not exist if they have never seen it themselves?