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It definitely could be related. If the gas cap is loose the car will put out a P0455 Large EVAP Leak error code. If you just ignore the light after you tighten the cap, it should go out after a few drive cycles, (drive cycle being; key on, start vehicle, drive several miles to warm the vehicle up, then several miles after its warmed up then parking and turning the vehicle off) Either that or you can go to a dealership or another shop and they can scan it and clear the code for you if it is indeed that related code. I would imagine it is, as I have seen this countless times in my career. Good luck!
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