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 capTerminals of ecu
Check instrument panel junction block (main body ecu)
Measure the voltage of the connectors.
If the result is not as specified, the junction block
(main body ecu) may have a malfunction. ...
Rear airbag sensor
Components
On-vehicle inspection
Check rear airbag sensor (vehicle not
involved in collision)
Perform a diagnostic system check (see page rs-
49).
Check rear airbag sensor (vehicle
involved in collision and airbag has not
deployed)
Perform a diagnostic system check ...
Diagnosis system
Description
The occupant classification ecu controls the functions of
the occupant classification system on the vehicle. Data
of the occupant classification system can be read in the
data link connector 3 (dlc3) of the vehicle. When the
system seems to be malfunctioning, use the intelligen ...