Fuel Tank Cap: Inspection

WARNING: This page is about a different car, the 2007 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT FUEL TANK CAP ASSEMBLY
1. Visually check that the cap and gasket are not deformed or damaged.
  If the result is not as specified, replace the cap assembly or gasket.
  
  Fig 1: Inspecting Fuel Tank Cap And Gasket Are Not Deformed Or Damaged
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002