Turn key over so the Lexus emblem is visible on the back. Above where the metal key goes into the plastic is a small screw - find a screwdriver small enough to unscrew this. Once the screw is out, pull plastic backing away from metal key and up. After shell is opened, you will see the housing for battery and buttons. There are a couple of possibilities for the plastic that houses the battery:
1. The housing has 2 small screws that must be taken out in order to get to the battery. Take these out, lift off the small plastic cover, and continue to replace the battery - which should be CR2016 3V. Put everything back together.
2. The housing has no screws to take out. Instead, the housing is opened using a coin or flathead screwdriver (directions on how to take the cover off will be on the plastic itself). Replace battery and you're finished.
Once battery is replaced, make sure the battery is good by pressing the lock or unlock button and watching for the small red light to flash when button is pushed. Red light is located next to the lock/alarm button.
CR1616
CR1616
Open the key fob, remove the battery and look and see what size it is.
Use a dime to open the key fob battery door on the key fob. New batteries are typically available at Radio Shack. Salesperson at same usually know how to open it.
Probably a CR1616. Open it up and see what battery it takes.
Open it up and check and see.
If you press the unlock button two times it should unlock all the doors.
Panasonic CR 1616
How do you change the battery in mazda 5 key?
open the lid and change it.
The fob has a pry slot and prys apart.
Your Lexus dealer (Parts Dept) will change it for you for the price of the battery, I just paid $4.33 (Sept. 2008). If you want to do it yourself, purchase a CR2032 3v battery (flat disc) from somewhere like Radio Shack or Fry's Electronics. To open the key fob, hold the fob key-ring side up, and do these two things at the same time: 1) slide back the top compartment (with arrow) 2) lift that same top compartment while it's pulled back Once the top is removed, use your fingernail to pull out the battery holder, then slide the battery out of that & replace.