Entry Answer-back Buzzer does not Sound: Description
WARNING: This page is about a different car, the 2012 Lexus LS 460. However, it is still accessible from the selected car via links, so may be relevant.
The smart access system uses the wireless door lock buzzer to perform various vehicle exterior warnings. When each warning's conditions are met, the certification ECU sends a buzzer signal to the front light ECU, and the wireless door lock buzzer sounds.