Replacing a key battery is as simple as driving to your Lexus dealership and having them replace it. However, if you want or need to do it yourself, check your owner's manual to get the correct battery size before you head out to the auto-parts store. Then you can get down to the business of opening up your key and replacing the battery.
Locate the screw. It is on the side opposite the control buttons.
Remove the screw with the screwdriver. Carefully store the screw in a safe place.
Open the cover by pushing it away from the key. You may need to exert pressure to slide it off.
Remove the battery/button control module by lifting it from the key frame.
Remove the two screws from the module and take off the lid. Carefully store the two screws in a safe place.
You will see a rubber O-ring and the battery in the center. Take out the used battery and replace with a new one. The positive side should be up.
Reposition the O-ring if it was dislodged while replacing the battery.
Place the lid on the module and install the two screws.
Place the module in the original position of the key frame and secure the key cover by installing the screw. All done.
