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 capCatalyst system efficiency below threshold (bank 1)
Monitor description
The ecm uses sensors mounted in front of and behind the three-way catalytic
converter (twc) to
monitor its efficiency.
The first sensor, the air-fuel ratio (a/f) sensor, sends pre-catalyst
information to the ecm. The second
sensor, the heated oxygen (ho2) sensor, se ...
Removal
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 seat belt pretensioner activation.
Remove radiator support opening cover
Remove front wheel rh
Remove no. 1 ...
Check for intermittent problems
Hint:
Inspect the vehicle's ecm using check mode. Intermittent
problems are easier to detect with the intelligent tester when
the ecm is in check mode. In check mode, the ecm uses 1
trip detection logic, which is more sensitive to malfunctions
than normal mode (default), which uses 2 trip detec ...