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.
Remove roof drip side finish moulding lh
Remove the 2 roof drip moulding joint covers from
the vehicle body.
Remove the roof drip side finish moulding and no. 2
Center ...
Instrument panel
Engine switch
Starting the engine/changing the modes
Emergency stop of the engine
When the engine will not start
Warning messages*1
Shift lever
Changing the shift position
Precautions against towing
When the shift lever does not move
Meters
Reading the meters/adjusting the instrument pa ...
Dtc check / clear
Check dtc
Connect the intelligent tester (with can vim) to the
dlc3.
Turn the ignition switch on and turn the intelligent
tester on.
Read the dtc by following the prompts on the
tester screen.
Hint:
Refer to the intelligent tester operator's manual for
further details.
...