Replacing the battery in the key

[jambo101]

2008 sedan, used to be i could activate the lights and locks from a good distance away now i have to be standing almost next to the car for the key to unlock the doors, after 7 years i'm assuming the battery in the key is finally needing replacement. i'm also assuming its just a matter of splitting the key taking out the old battery and installing a new one..
What battery am i looking for?
Thanks.

Nevermind ..i should have checked first.
http://www.yarisworld.com/forums/showthread.php?t=40684

[IllusionX]

i'm still on my original battery, and it has not failed me so far.

I'm not sure if the chip key does something to the battery.. it shouldn't though. But it also depends where you are.. these keyless frequencies seems to be easily disrupted.

I'm able to activate it inside the office at work, while it wont do 10 cars length in a parking lot.

[CTScott]

The transponder chip is a separate device from the remote.

You do just split the case to get at it, and the battery is a CR2016.

[jambo101]

Transponder?:confused: Will it need a replacement battery at some point?

[CTScott]

Transponder?:confused: Will it need a replacement battery at some point?

No. It is a passive transponder, which gets powered by the radio frequency from the reader which is built into the ignition switch assembly.

[auxmike]

So glad my 2008 doesn't have that. I put in the $49 Viper keyless entry....
Also, I can get my keys made at the hardware store for about $2.50. No transponder chip!