You say the passenger side, so the drivers side is free and not sticking, so the roof is scewwiff, (out of alignment) open it all the way (if its some kind of ratchet system and on rails when its open all the way back try giving it a push on the passenger side, forcing it back on the rail and track, it might realign it up again, other than that you have something stopping it from fully closing, check that out, it could be anything, a wire on the inside or even the cloth has come lose and is dragging along and caching on the window as it closes, take a good look at it as you open and close it a few times, (is the motor still trying to close it up when its stops fully on the drivers side?) you may have to take it apart to investigate it, i know nothing about the sun roof though, just a few suggestions for you to try, good luck