Refueling Vapors through Canister System
Refueling vapors vent through the canister while refueling. Fill is conventional (non-venting).
Refueling Vapors through Fuel Fill System
Refueling vapors bypass canister and vent through a vented fill to the fuel pump. This line is then closed with a sealed cap after refueling and diurnal vapors forced through the canister. This approach provides the least restriction during refueling.