Toyota Prius c 2014 Owner's Manual page 56

1-3. Opening, closing and locking the doors
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Electronic key battery-saving function
When battery-saving mode is set, battery depletion is minimized by stopping
the electronic key from receiving radio waves.
54
Press twice while pressing and
holding . Confirm that the electronic
key indicator flashes 4 times.
While the battery-saving mode is set, the
smart key system cannot be used. To
cancel the function, press any of the elec-
tronic key buttons.