How to Unlock Your Car If Your Key Fob Battery Dies

The solution is to find your mechanical key.

Jill Ciminillo | 

Jul 3, 2023 | 3 min read

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If you lock and unlock your vehicle with a key fob, you might wonder what to do when the battery dies. If you have a replacement coin cell handy, great: Just swap the fob’s battery and be on your way. If that’s not an option, there’s another way.

Mechanical Keys Still Exist

Carmakers change the design of their fobs over time and sometimes use different ones for different models. If locating the key isn’t intuitive, either check your owner’s manual or Google the phrase “How to get the mechanical key from a (year make model) fob” and you should find plenty of how-to videos.

How to Unlock the Door

Once you pull the mechanical key from the fob, you will need to find the corresponding slot on the vehicle. This may be obvious, on or near the driver’s-side door handle, but sometimes it’s on the underside of the handle or even inside it under a plastic cap. You may need to insert the key into a hole beneath the handle and pry off the cap to access the slot so it’s a good idea to consult your owner’s manual.

Unlocking your doors with the mechanical key is something you can try before you find yourself stuck with a dead key fob battery. However, if you’ve found this article after discovering the key fob issue, then consult Google or call a dealership for your brand of vehicle if you can’t figure it out.

Safeguards to Consider

Now, before you insert that key into the slot and turn it, take a minute to see if such an action will set off an alarm. You should be able to find this information in your owner’s manual or via an internet search. It’s possible that there’s a secret button or control inside the vehicle that you need to press to avoid a scene. Or you may need to start the car.

Some manufacturers program their vehicles to give owners 10 seconds or so to turn on the car after a mechanical-key entry before it’ll sound the alarm. But this presents a conundrum: How do you start a vehicle with push-button ignition if the key fob is dead? Most likely, it’s as simple as placing the dead fob in a designated spot or pocket — typically found somewhere in the center console — and pressing the ignition button.

If the alarm does sound and you’re in a panic to turn it off, disconnect the car’s battery by removing the negative (black) connector from its terminal.

Jill Ciminillo

Jill Ciminillo is a Chicago-based automotive writer, YouTube personality, and podcast host, with her articles and videos appearing in outlets throughout the U.S. Additionally, she co-hosts a weekly radio show on cars for a local Chicago station. Previously, Jill has been the automotive editor for both newspaper and broadcast media conglomerates. She is also a past president for the Midwest Automotive Media Association and has the distinction of being the first female president for that organization.