STEPS
TOOLS
Slide the switch on the fob to remove the key.
Once the key has been removed flip over the fob.
Remove the four screws to get access to the battery.
Remove the old battery.
Replace the battery with a fresh CR2032 battery.
Screw all the screws back in.
Put everything back together by lining up the hinges on the fob and the backplate.
Gently slide the backplate all the way down while pressing in the same switch that you used to remove the key.
Everything should be perfectly lined up!
Slide the key back in and your fob should have all the original functionality.
1.0 Prius key fob
1.0 CR2032 battery

How to replace the battery in a toyota prius key fob

Here's how to replace the battery on a 2004-2009 Prius remote entry key fob. You'll know your battery has died when the car won't start without the key in the ignition and keyless entry stops working.