Warning - Key battery low

You can replace it yourself. Go out and buy a CR1632 battery (or equivalent). Remove the metal key and use the tip to pop open the fob. (There's a little indent that matches the end of the key.) Gently lift up the circuit board to find the battery. Pop the old battery out. Put the new battery in. Carefully reassemble the key and you are good to go.

(I did this last week.)

 

Link to a good post of some step by step w/ pictures. For gen 3
Toyota Prius Smart Key Fob Battery Replacement Guide - 2010 To 2013 Model Years - Picture Illustrated Automotive Maintenance DIY Instructions

 

You might as well do both FOB's at the same time. My two FOB's quit within 2 weeks of each other.
Thankfully I had purchased a 4 pak of batteries.
Simple to replace!
They lasted from 03/2008 till now, 07/2013
5.5 years is not bad on a battery like that!

 

Yep, Wife wants hers too, a few $ now for peace of mind...
here is a you tube for gen 2, key fob batt replacement,

 

I change the batteries every year when I change my homes smoke detector batteries. I do this whether they need changing or not.

 

Here's a video for the 3rd Gen battery key FOB, no tools necessary!

 

changing batteries well before needed is kind of a waste, and they are not good for the environment.

 

The message has been going off on my for about a month now... suppose now that I know how, I should do it. Thanks for the instructions!

 

My Camry fob battery died one day. I didn't panic because I knew that holding the SKS key fob next to the Start button for a few seconds would work. Whew.

But, yeah change the batteries in your fobs.

SCH-I535

 

I ignored "key battery low" alert for about 2 months until the other evening when my smartkey wouldn't work. I pulled out the emergency key blade to gain entry and to retrieve the replacement battery I kept in the center console. It was very easy to install new battery. I used emergency key blade to pry smartkey open.

 

If you had the spare battery, why didn't you just change it?

There was a post here where someone changed the battery to the fob inside the car and dropped one of the screws down the center console.

Yes, the slot on the fob case is designed to be opened/pried with the end of the spare mechanical key.

SCH-I535

 

If you are paranoid about the battery doing dead, just purchase an extra battery and keep it in the glove compartment. It takes up no room. Personally, that isn't an economical way of dealing with the battery as the extra battery will lose some life just sitting in the glove compartment. But at least when you get that warning, you can immediately change the battery and have a lot of time to get to the store to buy a new battery.

 

No one is paranoid, and no need to hurry. I started getting low battery notices over a month ago. Finally I got a delivery of cheap CR1632 batteries from china. The 4-year old battery was 2.8V, not too bad. The new ones are 3.3V.

 

Glad I ran across this thread. Very good info.

 

That's a good time to clean the fob as well. It can get kind of gross from being in a pocket for so long Definitely an easy job -- and do both fobs at the same time for sure.

 

Where can these batteries be bought? Hopefully they are very common and can be picked up at Lowe's or even a grocery store (Kroger, Publix, etc), or even Wal-Mart.
I bought my Prius about a week ago and while the dealer finally found the 2nd keyfob, I didn't test it. He confirmed that it is the *correct* keyfob, but nothing makes it work, not even holding up to the start button.

Also, how long does the 'low battery' light stay on?

My 2 keyfobs are slightly different from each other...if it's truly for my Prius, shouldn't they be identical?

 

I got two identical fobs with my 2013, but as long as they both function, I would not worry about it. Have you checked the mechanical keys to make sure they open your door lock? This is your emergency entry method in case your electronic unlock function fails.