How To Change The Battery In A Toyota Key Fob

You may know the signs of a key fob with a bad battery: having to press the button multiple times or getting close to the car for activation to kick in. Sometimes the functions engage, and at other times, they don't. You can even run into problems using proximity keyless entry (touch-sensitive door handles) or push-button start. When these symptoms appear, it's time to replace the key fob battery. Fortunately, learning how to change the battery in a Toyota key fob isn't difficult. It's one of those DIY maintenance tasks that every car owner should know how to do, along with checking the oil and adding air to the tires.

Toyota key fobs vary slightly between models and years, but most use a coin-style lithium battery (usually CR2032 or CR2025). Newer Toyotas have a rectangular-shaped key fob that only has an emergency key hidden inside the housing. For instance, the image above shows the type of key fob used with the 2025 Toyota Camry. Meanwhile, older key fobs may have a traditional key blade attached to a multi-function fob or a stand-alone, oval- or rectangular-shaped key fob with a separate key.

Always consult the owner's manual (available on Toyota's website) for your particular model for precise battery replacement instructions. However, here's an overview with step-by-step details.

Modern key fobs have hidden features you might not know about. For example, on some more recent Toyotas, you can start the car remotely by quickly pressing the lock button three times and holding it down on the third press. For newer Toyota key fobs without an integrated key blade or a separate physical key, you can replace the battery by following these steps:

1. Remove the emergency key: Slide the latch on the side of the fob to release the hidden emergency key. Pull it out and set it aside.
2. Open the key fob: Using the tip of a flathead screwdriver (depending on the unit, you may be able to use the emergency key), gently separate the two halves of the casing at the point where the emergency key is stored. Be careful not to damage the plastic housing.
3. Remove the old battery: Use the screwdriver to carefully lift the old battery away from the bracket. Avoid touching the contact terminals, and take note of the battery's orientation (positive and negative sides). Inspect the battery bracket and terminals for any corrosion (a sign of a leaking battery). If there is no corrosion, proceed to the next step.
4. Insert the new battery: Place the new battery in the bracket so the orientation matches the placement of the old battery. Usually, this has the positive (+) side facing up.
5. Reassemble the key fob: Align both halves of the casing and gently squeeze them together until the fob is snapped shut.
6. Reinsert the mechanical key: Slide the emergency key back into its slot in the fob.
7. Test the new battery: Approach the vehicle and test the key fob's functionality to ensure the battery has been installed correctly.

The process for installing a new battery in an older Toyota key fob follows many of the same steps as that of a newer model. However, there's no hidden emergency key to deal with, only a built-in key blade or a separate physical key. In addition, the function buttons can easily become dislodged on some units, and the plastic may be more vulnerable to damage due to age. If you're curious about how different key fob designs evolved, check out the best and worst car keys ever made.

Exercise caution before proceeding.

1. Identify the opening point. Locate a slot along the edge of the fob housing where the two halves meet.
2. Use the correct orientation: Place the key fob with the function buttons facing down so they don't fall out of the open unit.
3. Open the key fob: At the opening slot, gently pry apart the two halves using the tip of a flathead screwdriver.
4. Follow steps 3–5 and step 7 from the section above.

For owners who prefer video instruction, Toyota's YouTube channel offers numerous model-specific tutorials on changing the key fob battery. You may need to try different search terms as Toyota has changed terminology over the years, ranging from "keyless entry" to "Smart Key." Adding "battery" and the model and year can help narrow the options.