I picked up a 2009 (well it's actually an early production 2010) Sonata from my neighbor with 155k on the clock. The car was throwing a check engine light for Evaporative Emissions Control Small Leak and whenever I'd try to fill the tank, the nozzle would click off if I tried to add any more than a trickle of gas. It would take about 10 minutes to fill an empty tank. I read up on this condition and found a helpful post on this site which lead me to check out the evap system located by the left rear wheel/suspension. There is a cylindrical plastic canister (not the big rectangular charcoal can) that's about 6" long and about 2 1/2" in diameter that connects to the big charcoal canister. I removed this and tried to blow through it in both directions. It was 99% clogged. I believe this is the a filter that captures gas fumes while you're filling the tank and pushing vapor out as you pump gas in. This is a sealed unit so I used a Dremel cut off wheel to cut along the plastic seam at one end of the cylinder. When it came apart, there was a spring, charcoal pieces, a screen and a filter material. I removed the charcoal material and put the rest of it back together and epoxied the top back on. I then reinstalled it on the car. My CEL stayed on for a few drives and then went out. 500 miles later and it has not returned. I believe that this canister had become clogged from "topping off" the tank with too much fuel and the evap system getting filled with gas which soaks the charcoal and makes it clog. Anyway, problem solved and it cost me nothing!