Do I Have to Reprogram My Fob After Battery Replacement

Published on: May 1, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

As a car owner, you know an electronic car key gives you remote access to your car’s door locks, trunk, alarm system, power windows, and the ability to start the engine. All of the above functions are possible depending on your key fob’s programming level. When your key fob fails to function after you have replaced the battery, it can be pretty annoying.

The most common question we got is, “do I have to reprogram my fob after battery replacement?Indeed, you need to. Since the key fob’s battery was replaced, the key was reset, and it is necessary to reprogram the key fob to the car. Nothing with the key fob works properly unless it is reprogrammed after the battery is replaced.

When the key fob stops working, you could be puzzled by why your key fob doesn’t work after replacing the battery; then, this writing may bring peace of mind. Resetting your automobile key fob is currently more straightforward than you might think. The key fob is built so that even non-technical people can reset it.

Moreover, if you have these issues, you are unlikely to be near a qualified vehicle mechanic or engineer. Using the techniques in this article, you will be able to easily reset your automotive key fob after replacing the battery without contacting an auto dealer, saving you time and money.

do i have to reprogram my fob after battery replacement

What is a Key Fob?

Key fobs are a great way to remotely unlock your vehicle. This compact security hardware device with built-in authentication is used to secure access to different electronic devices. A randomly generated access code appears on the key fob, and it changes every 30 to 60 seconds on average. A vehicle key fob is powered by a small lithium battery and is the key to communicating with your vehicle’s relay modules. 

The History of Key Fobs

The name “key fob” refers to a key chain and various other comparable objects and gadgets. The term “fob” is believed to derive from watch fobs, which were in use as early as 1880. The term “fob” refers to a decor that is attached to the chain of a pocket watch. Fobs, or key fobs, are also used to refer to key chains, remote auto starts and keyless access devices on hotel room doors.

The Battery’s Function in the Key Fob

We all know that battery-powered electronics might suffer from battery death after continued use. Sometimes you may face your key fob malfunctioning, making it impossible to lock or unlock your vehicle doors. Additionally, you may have a key fob signal loss, which makes accessing your vehicle incredibly difficult.

All these are a sign that you may need to change the battery. But after battery replacement, sometimes it doesn’t work correctly. The most common query we got is, “why won’t my key fob work after I changed the battery?Different car brands have different configurations of a key fob.

So it is important to follow the appropriate steps. Before taking any actions, first, you may need to figure out your car’s particular model. After replacing the battery, if something goes wrong with your key fob, you can quickly fix it yourself at home by following the below steps.

How Do I Reprogram My Key Fob After Replacing the Battery?

The steps below will demonstrate how you reset the key fob after replacing the battery, as most key fobs do not function appropriately after battery replacement. Not all vehicle brands allow you to reset your key fob easily.

However, the method described here is regarded as universally applicable. If the procedure does not work for your car, you must research how to reset your car’s key fob. You can get more extensive information in the automotive manual, which is available both online and in the vehicle.

1) Battery Replacement

Once you have determined that the key fob is malfunctioning due to a weak or dead battery, you should make every effort to have the battery replaced as soon as possible after discovering the problem. An unreliable key fob battery, on the other hand, might cause significant headaches and disorientation anytime you attempt to restart it.

The majority of the time, the batteries are inexpensive, simple to change, and readily available. To make things even easier, you can easily replace the battery by lifting the plastic cover on the back of the key fob. Remember that you should avoid touching the key fob circuit and pay attention to the battery’s positive and negative orientations when replacing the battery.

2) Enter Your Car

After replacing the battery, get into your car and lock all doors. Because leaving your doors open may interrupt the key fob’s reset process.

3) Turn On Your Car’s Ignition

Do not begin driving your car’s engine until you have secured a comfortable seating position and closed all doors. Remember, while your engine isn’t running, make sure the ignition isn’t set to radio mode.

4) Button Lock

After completing the third step, turn off the vehicle key and press and hold the lock button on the key fob. Rep the process three to four times, each time with the key in the ignition on. This operation alerts your vehicle’s electrical control unit that the key is in the ignition, and the signal is saved to your vehicle’s ECU.

5) Look For The Lock Sound

After completing the steps above, listen for a lock sound. The lock sound indicates that you have entered the vehicle’s key fob programming mode. After hearing this sound and confirming the key is in programming mode, push the lock button on the fob five times. This saves all relevant data, and the programming succeeds.

6) Extra Programming Remotes

By pressing the lock button on the key fob within the next ten seconds, additional remotes can be programmed after entering the programming mode and hearing the key fob’s alarm sound.

7) Disable The Vehicle’s Ignition

Turn off the ignition system to complete the programming process after you’ve completed all of the necessary procedures to reset your key fob.

8) Testing The Reset Key Fob

You should now be outside the vehicle with all doors closed. To ensure the functionality of the newly reprogrammed key fobs, test all unlock and lock buttons. Verify that all relevant controls are operating correctly and without lag or other difficulties.


The reprogramming of key fobs varies by individual and vehicle. So, if your key fob breaks and you need to unlock the car but forgot your keys inside, it will be challenging due to the increased protection.

We hope that this little guide will answer your query of “do I have to reprogram my fob after battery replacement?To be safe, you should check your key fobs once a week to ensure they function correctly while you’re out of the car or in an emergency.

The key fobs are also quite straightforward to use, and they also come with a configurable option that allows owners to add a vehicle monitoring feature. Some automobiles’ key fobs may not work with the preceding methods; in this case, it is wise to consult with an expert hardware programmer for your vehicle.

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About This Writer

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Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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