Entry Answer-back Buzzer does not Sound: Description
WARNING: This page is about a different car, the 2011 Toyota Corolla. 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 each warning's conditions are met, the certification ECU (smart key ECU assembly) sends a buzzer signal to the wireless door lock buzzer, and the wireless door lock buzzer sounds.