After refueling, turn the fuel tank cap until you hear a click. Once the cap is released, it will turn slightly in the opposite direction.

Caution
When replacing the fuel tank cap
Do not use anything but a genuine toyota fuel tank cap designed for your vehicle. Doing so may cause a fire or other incident which may result in death or serious injury.
Opening the fuel tank capRemoval
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the lh side.
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and ...
Opening the fuel tank cap
Pull up the opener to open the
fuel filler door.
Turn the fuel tank cap slowly to
open.
Hang the fuel tank cap on the
back of the fuel filler door.
...
Ventilation valve
Components
Removal
Remove no. 1 Engine cover (see page em-22)
Remove ventilation valve sub-assembly
Disconnect the ventilation hose from the ventilation
valve.
Using a 22 mm deep socket wrench, remove the
ventilation valve.
Inspection
Inspect ventilation val ...