There is a leak some where in the evap system. Check all your hoses leading to the canister. Check all your hoses at the canister. Check the gasket at the access for the fuel pump. Could also be a bad evap control valve or a vent control valve. If you don't see anything obvious you may need to take it to the dealer.
The other option is, (not legal) if you are open source or have an AP and do your own tunes, then you can simply disable the code. Anything related to the Evap system has no impact on how the car runs or performs so there should be no issues if you disable the code. Do this as a last resort though. It is better to have everything running properly IMO.