Entry Answer-back Buzzer does not Sound: Description
WARNING: This page is about a different car, the 2013 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
The smart key system uses the wireless door lock buzzer to perform various vehicle exterior warnings. When the conditions of each warning are met, the certification ECU (smart key ECU assembly) sends a buzzer signal to the wireless buzzer, and the wireless door lock buzzer sounds.