Auto Lock Function

WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

When the door is not actually opened within 30 seconds after the door has been unlocked by the unlock switch on the transmitter, all the doors are automatically locked. If any of the following conditions are detected, the wireless door lock does not function.

Any door is opened.
The ignition key is inserted into the ignition switch.
When the unlock detection switch of all the doors are locked.