I have a '13 Dodge Durango Crew 3.6 that displays the fuel cap light when I use ethanol free gas. Has anyone else experienced this?

 

Longshot. From page 313 of my '13 OM.
Certain conditions, such as a loose or missing gas cap,
poor fuel quality, etc., may illuminate the light after
engine start. The vehicle should be serviced if the light
stays on through several of your typical driving cycles. In
most situations, the vehicle will drive normally and will
not require towing.

How the car knows that the fuel is different is a question to ask a dealer unless someone here knows.

 

if its not a flex fuel vehicle it has no way of knowing the OH content of the fuel.

All vehicles know when a refueling event has happened. the vehicle probably is running gross leak check after the fueling event and is not seeing the esim close. there probably is other dtc set besides the gross evap leak/cap missing.

 

Out 2012 Dodge Durango SXT does turn on the check engine light (evap leak codes) or turn on the gas cap light when we fill up with grocery store brand gas.

Claus