ORing on the capless fuel system is to seal vapors and pressure in the tank. While fueling, 8 times out of 10 the Oring catches on the spiral of the fuel fill up nozzle, dragging it out and riding on top of the flapper in the fill neck. Within a short period of time, the check engine light comes on but will go out after a couple of hundred miles of driving. Poorly designed and when explaining it to service writers, they look at you like a calf looking at a new gate. A fix would be to keep the Oring in place instead of being able to be dislodged by the fuel nozzle.