How to Change the Battery in a Smart Key

by Pilar Ethridge
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Smart Key generally refers to a type of keyless electronic entry system for automobiles. Since 1999, several manufacturers have used this system by different names. In particular, Toyota refers to its keyless entry devices as Smart Key Systems. Not only do Smart Keys unlock the car's doors; in some instances, they can also turn on the lights and start the engine. Fortunately, the battery in a Toyota Smart Key System can be changed without the help or cost of a technician.

Step 1

Call a local Toyota dealership to find out what type of battery you need to get for the Smart Key. You will then need to locate the battery at a supply store or home improvement shop. By purchasing the battery before you attempt to replace it, you'll eliminate the guesswork.

Step 2

Pull out the mechanical key that is at the bottom edge of the Smart Key. Use only this key as your tool to probe the Smart Key. You will not need a knife, pencil or other sharp object to get to the battery.

Step 3

Pry open the smart key by locating a thin slot in which the mechanical key fits into comfortably. You should not have to force the key into any part of the outer casing.

Step 4

Turn the key as if it is a lock and you should see the outer casing open in half. Pull it apart carefully.

Step 5

Look for the round battery on the small circuit board inside the Smart Key. If the battery is not on the side of the circuit board that faces you, use the mechanical key to lift the circuit board from the casing and you will find the battery on the other side.

Step 6

Remove the old battery and insert the new one in its proper place. Then put the two sides of the casing back together and insert the mechanical key into its proper slot.

Step 7

Test the key right away to make sure you have successfully completed the installation.

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