Here is the charcoal cannister, the "P" port comes from the throttle body "P" fitting (red hose), the black hose goes back to the gas tank (vents gasoline fumes to the cannister). The third line that exits the bottom of the cannister is the fresh air vent line and just hangs down towards the frame. It provides the fresh air that flushes out the gasoline fumes trapped inside the charcoal when the engine vacuum applies vacuum to the purge port of the cannister.   (19/26)