Why Hyundai key fob is not working after battery change

The primary responsibility of every car owner is to ensure the machine is running efficiently whenever called to action. However, problems arise.

As most modern vehicles use electronic control units, issues might halt our plans, whether mechanical or electronic parts.

Most vehicles nowadays rely on key fobs or electronic car keys to function. Key fobs control almost every activity when you want to run your car.

For instance, you need the key fob to unlock the car, start the engine, open and close the trunk, manage the alarm system, and even power windows.

But key fobs use batteries to function, and at some point, the battery drains. So you will need to replace it. Unfortunately, the key fob battery might fail to work after replacing the key fob battery.

So, what could be the problem? And what could be the source of that problem? This is an issue many car owners rely on the key fob for most functionalities experiences.

Your car’s key fob might not work after replacing the battery because of various issues like;

  • You mishandled the key fob circuit
  • The key fob’s buttons are worn out
  • The key fob is spoiled and many other reasons.

Luckily, these problems can be solved and get your key fob on track. Keep reading to learn more about these and other causes of key fob failure to work after changing the battery.

Why is my Key Fob not Working after Replacing the Battery?

Your key fob might have other problems that never surfaced until you changed the battery. So, when you replace the key fob’s battery, various issues might hinder it from functioning. Let us get deeper into these problems.

Worn out Key Fob Buttons

Key fob buttons are not there to last forever so they will wear out over time. Sometimes, the buttons might be worn out but remain in contact with the circuit.

However, with slight interference when charging the battery, the buttons fail to function. You can notice this by repeatedly pressing the button when the button functions after squashing it in a certain way or when one button functions and the other does not.

Also, if the covering plastic is out of place, it signals a problem in the key fob. You can open the remote and align the buttons to create contact with the circuit, and if it fails, you get another key fob.

Broken Door Lock

Sometimes problems coincide. When you change the key fob battery, your car lock might fail to work, not because of the key fob but because the lock is broken and the problem has just surfaced.

This might leave you wondering, but it is easy to discover this problem. These signals can help you know if the lock has a problem.

  • The lock fails to function even after opening it manually or with a key.
  • The key fob opens some door locks.
  • The door locks fail to open, whereas the signal light has flashed.
  • The lock moves without thoroughly engaging or disengaging.

Spoilt key fob

Car key fobs can quickly spoil due to certain factors like water. But these problems might not surface until there is a slight change in the key fob. So, when you change the key fob battery, it might fail to work. Some signs can confirm the key fob is spoiled. They include:

  • The spare key is working
  • Buttons failure to move
  • The key fob is broken
  • If the key fob is damaged, the only solution is to replace it.


When you change the key fob’s battery, high chances are the key will reset and will fail to function after that. These two signals can help you realize the problem faster.

  • If all spare key fobs fail to function too
  • The key fob entirely stop functioning

If this is the problem, you can summon a professional to reset the key fob or do it yourself by following these steps.

  1. After changing the battery, get in the car and close all the doors to avoid reset process disruption.
  2. Turn on the vehicle’s ignition system without starting the engine.
  3. Press and hold the remote’s lock button and turn off the vehicle key. Repeat the process three or four times.
  4. After the third step, listen for the car’s lock sound, which indicates you have entered the key fob’s programming mode. After the sound, press the remote lock button again within five seconds.
  5. If there are other remotes you want to program, this is a significant step. After entering the programming mode, press the key fob’s lock button within ten seconds. This will program the other additional remotes.
  6. Turn off the car’s ignition system to close the programming process.
  7. Step out of the car and lock all the doors to test the key fob. Test all the lock and unlock buttons to affirm the key fob is appropriately functioning.

However, this programming method does not work on all vehicles, so you should first consult before trying the process to avoid damaging your vehicle’s ECU.

Does Resetting the Key Fob Fix the Issue?

If the key fob problem resulted from resetting itself after changing the battery, resetting the key fob can fix the problem. However, if the origin of the key fob problem was not resetting itself, this process cannot fix the problem. Also, you should never attempt to reset the key fob without consulting because some vehicles’ ECU can be damaged.

Should you Reprogram the Car after Replacing the Battery?

Yes, you need to reprogram the car after changing the battery. Like I said earlier, changing the battery disrupts the regular program of the vehicle. So you will need to reset it.

Can you start a Hyundai car Without a Key Fob?

Hyundai vehicles have a digital key feature to open the car with your smartphone. It is an application owners can rely on if their key fobs are not functioning.

The only setback is that the application is only available on specific Android devices and can be achieved through NFC.
So, yes, you can unlock and start Hyundai without a key fob, but you must have the digital key feature on one of the specified android devices.

How do you Start a Hyundai with a Dead Key Fob?

You might be wondering how one can start a car with a dead-key fob, but Hyundai cars are unique. There are two ways you can start your Hyundai with a dead key fob.

  • Use the end or back of the dead key fob to press the start button while pressing the brake.
  • Put the dead key fob in the smart key slot with buttons facing up and press the start button while pressing the brake.


Most modern vehicles use electronic car keys to operate, but the key fobs use batteries that need replacement after some time.

As discussed above, the fob might fail to function after changing the key fob battery due to various causes. Some problems can be fixed, while others require key fob replacement.

There are various ways you can fix the issues and keep your key fob functioning. Most importantly, it is better to note that you will need to reprogram the car after changing your key fob’s battery.

Hyundai vehicles are unique and can start with a dead key fob following the above-mentioned processes. Learn the basics of these key fobs so that whenever a problem arises, and you are in the middle of nowhere, you can solve the problem.

The signs above can help you determine the cause of the problem and will be easier for you to solve the problem.

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