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 capOccupant classification sensor power supply circuit malfunction
Description
The occupant classification sensor power supply circuit consists of the
occupant classification ecu and
the occupant classification sensors.
Dtc b1793 is recorded when a malfunction is detected in the occupant
classification sensor power
supply circuit.
Wiring diagram
...
Reassembly
Bearing position
Standard bearing position
Install differential gear lube apply tube
Install the apply tube and clamp to the transaxle
housing with the bolt.
Torque: 9.8 N*m (100 kgf*cm, 87 in.*Lbf)
Notice:
Make sure to insert the pipe to the stopper.
Instal ...
Gcwr, twr and unbraked twr
Confirm that the gross trailer weight, gross combination weight, gross
vehicle weight, gross axle weight and tongue weight are all within the
limits.
Gcwr*
2Wd models: 5985 lb. (2715 Kg)
Awd models: 6100 lb. (2765 Kg)
Twr*
1500 Lb. (680 Kg)
Unbraked twr*
1000 Lb. (450 Kg)
*: ...