The emergency flashers are used to warn other drivers when the vehicle has to be stopped in the road to a breakdown, etc.
Press the switch.
All the turn signals 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
emergencyProblem symptoms table (2006/01- )
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms
are listed in order of probability in the "suspected area"
column of the table. Check each symptom by checking the
suspected areas in the order they are listed. R ...
Removal
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove generator assembly
Remove the generator assembly from the vehicl ...
If a warning light turns on or
a warning buzzer sounds
Calmly perform the following actions if any of the warning
lights comes on or flashes. If a light comes on or flashes, but
then goes off, this does not necessarily indicate a malfunction
in the system. However, if this continues to occur, have
the vehicle inspected by your Toyota dealer.
Actions to ...