You can replace a Lexus key fob battery yourself in about five minutes
Most Lexus key fobs use a coin-cell battery—usually a CR2032 or CR2050—that you can buy at any pharmacy, supermarket, or hardware store for two to five dollars. The battery typically lasts three to four years before the fob stops locking or unlocking your car reliably. You do not need to visit a dealership or call a technician. The fob opens with a small flathead screwdriver or a coin, and the battery slides out and in without tools.
The exact steps depend on which Lexus model and fob generation you have, but the process is nearly identical across all recent models. This guide covers the most common fob designs. If your fob looks different or does not open as described, your owner's manual will show the specific method for your year and model.
Key Takeaways
- Lexus key fobs use a CR2032 or CR2050 coin-cell battery that costs two to five dollars and lasts three to four years.
- You can open the fob with a flathead screwdriver or a coin by inserting it into the slot on the fob's edge and twisting gently.
- The battery slides out of its holder; note which side faces up before you remove it so you install the new one the same way.
- After inserting the new battery, snap the fob halves back together and test the lock and unlock buttons before you drive.
Identify your battery type before you buy
The easiest way to know which battery your fob needs is to open it and look at the old battery itself. The battery type is printed on the flat side—CR2032 is the most common, but some Lexus fobs use CR2050, which is slightly thicker. If you cannot open the fob yet, check your owner's manual or search online for your specific model year and fob style.
You can also call your Lexus dealership parts department with your vehicle identification number (VIN) and they will tell you the correct battery. Many dealerships sell the battery for eight to twelve dollars, which is more than a pharmacy charges, but the information is free.
Open the fob using a flathead screwdriver or coin
Look at the edge of your key fob for a small slot or seam. On most Lexus fobs, this slot runs along the side where the two plastic halves meet. Insert a flathead screwdriver or the edge of a coin into the slot and twist gently—do not force it. The fob should pop open into two halves.
If the fob does not open easily, try a different spot along the seam. Some fobs have the slot on the top edge rather than the side. Once you find the right spot and explore gentle pressure, the halves will separate. Set the back half aside in a safe place so you do not lose the small spring or contact inside.
Remove the old battery and note its position
The battery sits in a shallow plastic holder in the center of the fob. Before you touch it, look at which side is facing up—the positive side (marked with a +) or the negative side (unmarked). Take a photo with your phone if you want to be certain. This matters because installing the battery upside down will prevent the fob from working.
Slide the battery out of its holder with your fingernail or the edge of a plastic card. Do not use a metal tool, as you could scratch the circuit board. The battery should slide out easily; if it is stuck, try gently rocking it side to side.
Insert the new battery with the positive side facing the same direction
Take your new CR2032 or CR2050 battery and slide it into the holder with the positive side facing the same direction as the old battery was facing. The battery should fit snugly but not require force. If it does not slide in smoothly, check that you have the right battery type and that it is oriented correctly.
Once the battery is seated, you can close the fob. Align the two halves so the edges line up evenly, then press them together firmly until you hear or feel a click. The fob should snap shut without gaps.
Test the fob before you rely on it
Stand near your Lexus and press the lock button on the fob. You should see the lights flash and hear the locks engage. Press the unlock button and confirm the lights flash again. If neither button works, open the fob and check that the battery is installed with the positive side facing the correct direction.
If the fob still does not work after you have reinstalled the battery correctly, the circuit board may be damaged or the battery contacts may be corroded. In that case, you will need a replacement fob from your Lexus dealership. A new fob typically costs sixty to one hundred fifty dollars, depending on your model.
When to replace the battery again
A new battery usually lasts three to four years in normal use. You will notice the fob starting to fail when you have to press the buttons multiple times to lock or unlock the car, or when the range decreases and you have to stand closer to the vehicle. These are signs the battery is running low and should be replaced soon.
If you replace the battery and the fob still does not work at full range, the issue may be with the fob's antenna or circuit board rather than the battery. A dealership can diagnose this, but repair or replacement is usually more cost-effective than troubleshooting.
Frequently Asked Questions
Can I use a different battery type if I cannot find the exact one?
No. CR2032 and CR2050 are not interchangeable—CR2050 is thicker and will not fit in a fob designed for CR2032. Using the wrong battery can damage the fob or prevent it from closing properly. Buy the correct type for your model.
What if the fob will not open with a screwdriver?
Try a coin instead—a dime or penny often works better than a screwdriver because the edge is thinner. If the fob still will not open, check your owner's manual for your specific model, as some older or newer Lexus fobs have different designs. Do not force it, as you can crack the plastic.
Is it safe to handle the battery with my bare hands?
Yes. Coin-cell batteries are safe to touch. Wash your hands afterward if you prefer, but there is no risk from brief contact. Avoid touching the flat sides of the battery if possible, as skin oils can reduce contact quality, but this is not a major concern for a fresh battery.
Do I need to reprogram the fob after changing the battery?
No. Replacing the battery does not erase the fob's programming. Once you install the new battery and close the fob, it should work when ready without any reprogramming steps.
What should I do with the old battery?
Most pharmacies and supermarkets have battery recycling bins near the checkout or customer service desk. You can also take old batteries to an electronics recycling center. Do not throw them in the trash, as they can leak chemicals into landfills.