Overfill Check Valve
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2003 Toyota Tundra, 2003 Toyota Tacoma, 2003 Toyota Sienna, 2003 Toyota Sequoia, and 2003 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
Individual component testing is not available from manufacturer. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister, overfill check valve and fuel EVAP system. See appropriate FUEL EVAP SYSTEM TEST.