DTC P2419, P2420: Evaporative Emission Pressure Switching Valve Stuck ON; Evaporative Emission Pressure Switching Valve Stuck OFF: Description
WARNING: This page is about a different car, the 2006 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
The circuit description can be found in the Evaporative Emission (EVAP) system (see EVAP System (2005/05-2006/01) ).