Like any battery-operated device, periodically changing a battery in a key fob is necessary. Unresponsive car key fob batteries or the fob’s inability to recognize your vehicle might mean dead batteries. Knowing how to change the battery in a key fob prevents unexpected lockouts.
Replacing the key fob battery is easier than you think. Steps can vary between manufacturers, but the overall process remains similar. Tough, urgent situations may require help from a professional automotive locksmith. Although, you can usually change the car key battery yourself.
“Knowing how to change the battery in your key fob is a great thing to know. If your key fob stops working, you’ll be able to fix it yourself – saving the cost and hassle of hiring someone else to do it.”
– Steven Radja, Quicksmith
This article will show you how to replace a car key battery. We’ll go over the key fob battery replacement steps and what to do if replacing the fob battery doesn’t work.
How Do You Change the Battery in a Key Fob?
Before we get into how to change car key batteries, let’s take a quick look at how key fobs work and their anatomy.
A key fob is essentially a miniature remote control. Like TV remotes, car remotes use a microchip and antennae to detect signals. These are the parts of a typical fob.
- RFID chip: An RFID (Radio-Frequency Identification) chip creates electromagnetic fields to detect its associated objects, like your car. Your fob’s RFID chip is inside its casing.
- Antenna: A key fob’s antenna emits the RFID chip’s frequencies to locate the object. The antenna is usually small, internal, and unseen on modern car fobs.
- Buttons: Most car fobs have a small button or buttons on their casing. The buttons trigger the chip and antenna to release a frequency.
- Plastic casing: The plastic case protects all the fob’s internal parts.
These components (except the casing) can’t do their job without power. That power comes from the fob battery. As such, it’s crucial to replace the car remote’s battery whenever that power runs low. Here’s how to change the battery in your car key fob.
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1. Check to See Which Batteries You Need
Your fob won’t work if you replace the fob battery with the wrong one. The type of key fob you have determines the types of batteries you need. The plastic casing should indicate the required kinds of batteries. Look for this indication and purchase your replacements accordingly.
2. Find the Seam on Your Key Fob
You need to open your fob to change the battery. Car key fobs open in a clamshell style. That means you can snap the fob open or close along a seam that separates it into two halves. On most fobs, this seam is along the side and divides the back and front.
3. Gently Pry Open the Fob
Knowing how to open your car fob is just as important as knowing how to change the fob battery. Vehicle manufacturers have different styles of key fobs, and each open slightly differently. Refer to your drivers manual for specific instructions on how to open your vehicle’s key fob.
A general guide to do so is below.
How to Open a Key Fob
Use a flat screwdriver, small coin, or tough fingernail to open your fob at its seam. Be gentle with the process to avoid internal or external damage.
- Press the coin, your fingernail, debit card edge, or other sturdy, flat object between the two pieces of your fob’s case. It will be along the side of the fob. Do not try to pry your fob apart at the buttons or back surface, this will damage the device.
- Gently twist the tool you’re using to ease the fob casing apart. Go slow so you don’t crack the case or damage the delicate wires within it.
- If you can’t gain access, try prying the fob open from a different spot along the fob’s seam. Or try a different tool.
4. Locate Each Battery’s Positive and Negative Ends
Car key batteries are flat and round. Each side is embossed with a positive or negative symbol. Locate these symbols on your old and new batteries. It’s important to know how to replace the car key battery with the correct orientation. Otherwise, the charge won’t flow properly.
5. Replace Car Fob Battery
Replace the remote car key battery by inserting the new one in the same positive/negative orientation as the old one. Your old batteries should pop out easily thanks to an inbuilt spring. If not, add some extra force with the same device you used to open your casing.
6. Put the Key Fob Back Together
After replacing the battery in the car key fob, close the casing. Check to make sure changing the car key battery fixed the problem. Test your fob’s lock/unlock features or any other functions to ensure they’re working correctly.
If your fob still isn’t working, review how to change the battery in the car key fob. A small error at any point in the process could affect your results. For example, make sure each battery is secure and correctly oriented.
Knowing how to answer the question: “how do you change a battery in a key fob” should help you in most emergency lockout situations for your car. Battery replacements are the most common key fob issue. However, there are other potential problems that a new battery won’t fix.
| Did you know… Audi key fobs need to be opened in a unique way? Check out how in the video below. |
What if Your Fob Still Doesn’t Work After You Replace Car Key Battery?
If a car fob battery replacement doesn’t help, there may be a different issue. Here are four common key fob problems that replacing car key fob batteries won’t solve.
1. Damage
If your transmitter is damaged, your fob can’t detect your car. Electrical damage, water damage, or trauma, such as frequent drops, can damage your fob. Even if you know how to change the battery on your car key, you may not know how to fix this damage. You’ll need professional help.
| Tip It’s best to keep your car and house keys separate. Too many keys on one keyring can cause confusion and the extra weight can damage your ignition or car fob. |
2. Deprogramming
RFID chips are specifically programmed to pair with certain objects. That’s why your car’s fob only works for your car. Replacing the battery on your fob won’t help if your chip is corrupted. Instead, check your user’s manual to see how to reset your fob or contact a locksmith.
3. Worn Buttons
Your buttons could be why your fob isn’t working after you change the battery on the key fob. Fob buttons connect to an internal circuit board that communicates with your RFID chip. Worn-down buttons don’t connect as well. In this case, you need to replace your fob.
4. The Problem is the Car Lock
Sometimes, the problem isn’t with the fob, it’s with the car. Broken car door latches could leave your car doors stuck in the lock position. Manually turn the key in your car door lock to test if the lock is the issue. Contact a locksmith to get you into a car that’s stuck on lock.
| Tip Most keyless fobs have a small backup key inside their casing. Check for a small sliding button on the back of your fob. Slide or press this button to pull the key from its casing. |
Frequently Asked Questions
1) Where can I get my key fob battery replaced? | You can replace your key fob battery at most hardware stores, automotive shops, or electronics retailers. Many car dealerships also offer key fob battery replacement services. If you prefer professional assistance that’s quick, Quicksmith’s automotive locksmiths can handle the replacement for you. Our mobile team will come to you and provide fast, reliable service to ensure your key fob is working properly. |
2) Do I have to reprogram my key fob after I change the battery? | In most cases, you do not have to reprogram your key fob after changing the battery. The key fob should retain its programming even when the battery is replaced. However, if your key fob is still not working after the battery change, you might need to reprogram it. Check your car’s user manual for reprogramming instructions or contact a professional locksmith for assistance. |
3) How do I know my key fob needs a new battery? | You might need a new key fob battery if your car is not responding to the fob’s commands or if the range at which the fob works has decreased significantly. Other signs include the key fob working intermittently or the buttons requiring multiple presses to function. Replacing the battery is usually the first step in troubleshooting a malfunctioning key fob. If these issues persist, consider consulting a professional for further diagnosis. If you’re located in Illinois, Quicksmith is a top emergency locksmith you can call. |
4) How can I charge my car key battery? | Most key fobs have batteries that cannot be recharged and must be replaced when they run out of power. These typically use small, round lithium coin batteries like CR2025 or CR2032. However, certain brands, such as BMW and Land Rover, offer key fobs that charge while inserted in the vehicle’s ignition. This allows the battery to recharge automatically as you drive. Always refer to your car’s user manual for specific instructions related to your key fob. |
Call Quicksmith if You Need More Than a Simple Car Key Battery Replacement
Some manufacturers make changing batteries in your key fob more difficult than others. If these steps don’t work for the battery in your key fob, Quicksmith’s professional locksmiths can figure it out for you or show you how to replace the battery in your key fob.
Alternatively, we can troubleshoot other issues to see if a car key battery change really is what you need. If we find another problem, we’ll fix it.
Our team has experience across a range of car makes—whether you need help with a Toyota, Audi, GM, Subaru, or Honda key fob, our fast-acting locksmiths will find a way to get you into your car. We provide 24/7 service in Naperville, Aurora, and surrounding areas.
Give us a call at 866-205-6412 for lightning-fast automotive locksmith services. If you have an ongoing issue or know that your car key batteries are dead, contact us for a free assessment.