Why Does My Key Fob Not Work After Replacing Battery? (9 Reasons Why)

Key fobs are nifty inventions you can use to open your car doors without needing your keys. While a key fob is convenient to have, there are times when it can start malfunctioning.

If your key fob stops working after replacing the battery, you may wonder what happened. We looked up the facts, and here is what we learned about the matter!

Why Does My Key Fob Not Work After Replacing Battery?

Key fobs do not work after replacing the battery because the contacts under the buttons get worn out. Additionally, damage to the key fob or wiring system for the car can affect the key fob. Also, a key fob can get accidentally deprogrammed, or you may be using the wrong sequence for your car.

Are you interested in learning more about why your key fob did not work after a battery change? We compiled a list of possibilities below, so read on!

1. Worn-Out Buttons

A common reason your key fob does not work after you replace the battery is that your key fob’s buttons are worn out.

Typically, your buttons have contacts, and when you press the button, the contacts will send signals to a circuit board.

But, if you have an old key fob that you use a lot, the button contacts in the key fob will eventually wear out.

Normally, you will know that you have worn out contacts when the plastic on the key fob is coming off, and you can see the contact.

Also, not all of the button contacts may be worn out. For instance, if you can open your doors but cannot close your doors, your key fobs lock buttons are worn out.

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Usually, it is best to get a new key fob that is compatible with your car instead of trying to fix the contacts on the key fob.

2. Deprogrammed Key Fob

Key fobs are usually programmed to lock and unlock doors, but your key fob could stop working because it was deprogrammed.

When your key fob gets deprogrammed, all the existing keys will be removed from the access list, so the key fob will not work on your car.

Typically, deprogramming occurs if you press a series of buttons on your key fob, which would trigger a sequence to deprogram the key fob.

As such, you need to refer to your key fob’s manual to see how to reprogram the key fob to your car.

3. Broken Lock

In some cases, your key fob’s battery may not be the problem because the issue could be with your car’s door lock.

Therefore, you need to fix your car door lock to open your car doors and use your key fob, but you need to determine what is wrong with your car door lock first.

For instance, the door panel could have a broken connection that is keeping the door lock stuck, or the door latch is busted.

Normally, you will know you have a door lock issue if you cannot manually open the door with a regular key, or you can open the other car doors with your key fob.

4. Multiple Vehicle Programming

Some key fobs can be programmed to be used on multiple vehicles, which can be why your key fob does not work despite a battery change.

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Further, if your key fob is programmed to multiple cars, you need to use a sequence to decide which vehicle the key fob will open.

Therefore, you may use the wrong sequence of buttons for your car or not realize that your key fob is currently in a programmed state for a different car.

Usually, you can just use the button sequence for your targeted car to make your key fob work again.

5. Damaged And Disconnected Wires

Damaged And Disconnected Wires

If you recently removed and reinstalled side panels or dashboard panels, it could be the reason your key fob does not work.

That said, wires get exposed when the panels are removed, which can lead to disconnection or damage.

Usually, you can tell that it is a wiring issue if other electrical devices do not work, such as your lights, car horn, etc.

As such, you need to have a mechanic look for any disconnected or damaged wires to fix the issue.

6. Wrong Battery

If you got a new battery without checking the exact type that your previous key fob used, you probably got the wrong battery.

Generally, you can tell if you got the right battery by checking the voltage, and most key fobs will use batteries that show 3 to 3.6 volts.

Therefore, be sure to carefully inspect your key fob’s previous battery to compare it to the new one to find out if you have the same type of battery.

7. Damage To The Key Fob

Other than normal wear and tear, physical damage to the key fob can make the key fob stop working.

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Usually, the damage will occur due to blunt force, water, circuit board scratches, and such. Plus, the damage does not have to be visible to make it affect your key fob.

8. You’re Too Far Away From Your Car

Occasionally, some key fobs will only work when you are at a specific distance from your car.

That said, if you got a new battery, but your key fob does not work, try to use your key fob next to your car to see if the distance was the issue.

9. Blown Fuse

Sometimes, the fuse for a module or control circuit of your keyless entry system can blow, so your key fob will not work.

To fix this, you have to find the corresponding fuse in your car and replace it to use your key fob again.

To know more, you can also read our posts on Ford Focus key fob is not working, why your key won’t come out of the ignition, and how to turn off car alarm without key.


Normally, key fobs just need a battery change to start working again, but that will not always fix the problem.

Still, key fobs can stop working despite a battery change due to damage, blown fuses, worn-out button contacts, and more.

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