Smart Door Lock Function
WARNING: This page is about a different car, the 2008 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
If the driver gets out of the vehicle carrying the electrical key and pushes the lock SW on the door handle, then when all doors are being locked, the certification ECU sends a signal both inside and outside the passenger room to confirm the location of the electrical key. If the key is confirmed to be outside the vehicle and not inside it, then the doors will be locked. Additionally the door ajar alarm will sound whenever a door is not shut properly when the lock SW on one of the door handles is pushed.