Code P1401, Already replaced fuel canister.
 

I recently took my 2003 Accent to a mechanic to address difficulties I was having with fueling up the car. Specifically, the gas pump repeatedly cut off on me as if the tank were full when it really wasn't. They replaced the fuel canister and cleared the code, and although it did fix the problem I had with pumping gas, the code returned after a few days, and it was P1401 again. Can anyone tell me what else might be causing this code to come up?