The emergency flashers are used to warn other drivers when the vehicle has to be stopped in the road due to a breakdown, etc.
Press the switch.
All the turn signal lights will flash.
To turn them off, press the switch once again.

Emergency flashers
If the emergency flashers are used for a long time while the engine is not operating, the battery may discharge.
If your vehicle has to be
stopped in an
emergencyCustomization
Your vehicle includes a variety of electronic features that can be
personalized to your preferences. The settings of these features
can be changed by the meter control switches, on the audio system
screen or at your toyota dealer.
Customizing vehicle features (audio system screen)
Audio system ...