Blog Car Care Advice Key Fob Battery Low Warning: What It Means + How to Fix
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Key Fob Battery Low Warning: What It Means + How to Fix

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You’ve clicked your fob button multiple times, but you still can’t get your car door open. After several attempts and pulling at your door handle, you finally get the door to unlock.  

Now that you’re inside, you notice a ‘key fob battery low’ light on your dashboard which brings several questions to mind, like what it means, how to replace the fob batteries, and how to start your car with a low fob battery

Well, we’ve got you covered! 
We’ll discuss all that and answer some other key fob-related questions

This Article Contains

Let’s unlock the information.

What Does the “Key Fob Battery Low” Light Mean? 

The dashboard warning light system helps update drivers on the status of their vehicles. 

The ‘key fob battery low’ light on the dashboard represents a low battery warning for your keyless remote battery. Ignoring this low battery indicator means you’ll start experiencing issues. 

Worst case scenario: 
If you disregard this low battery warning and the keyless remote battery dies, you could end up locked out of your car or even stranded. 

However, the fob is not powered through your car battery, but rather by a CR2032 battery inside — so it’s neither a costly nor difficult fix. As such, it’s best to replace a low key fob battery ASAP

To avoid the worst-case scenario, let’s see how you can tell your keyless remote battery is low. 

What Are the Signs of a Low Key Fob Battery?

There are a few things that point to your key fob battery being low:

Now that you’re certain about a low fob battery, let’s see how to replace it to avoid having a fob with a dead battery.

How To Replace a Key Fob Battery

Luckily, the battery replacement process is very straightforward. 
Here’s how to do it:

1. Get the Right Battery

There should be an embossed number on the side of your car key indicating the type of battery you need. Purchase a new battery as indicated on your car key fob.

2. Open the Fob Key

Locate the latch, switch, or screw at the back of the car key fob and open it using your fingernails or a small flathead screwdriver. Pull apart the two halves once your fob’s battery cover is open.

3. Remove the Old Battery

Some fobs may have paper in between the old batteries. If so, carefully remove the old battery set one at a time and don’t damage the paper. 

4. Do a Battery Change

Place the new battery inside the fob like you removed the old ones. Be extra careful not to break the paper between the two batteries (if it’s there) when doing the battery replacement. 

5. Close Up the Fob and Test the Fob Button

Once the battery change is complete, test to see if everything works fine. If your fob button isn’t working, try to reset the programming instructions. Here’s a summary of the reset programming instructions:

If you don’t have access to new batteries and need to open your car immediately, we’ve got the solution. 

How Do You Unlock Your Car With a Dead Fob Battery?

Car manufacturers considered the dead battery issue when designing the fob. They’ve installed a backup mechanical key inside the fob, so you don’t have to visit a service center. 

Here’s how to access the mechanical key:

  1. Locate and press the small release switch behind your fob.
  2. Remove the battery cover.
  3. Open the fob to access the spare metal key — and voila, you can now open your car!

You can also refer to your owners manual to check where to find the spare key. 

Additionally, some manufacturers have a remote unlock app you can use to get into your car with a dead remote battery:

Now that you’ve gotten in your car, wondering how to start your vehicle with a low fob battery? Let’s discuss. 

How Do You Start a Car With a Low Battery Fob

Vehicles with the standard insert key ignition can use the spare metal key. But key battery low situations are different for push start button vehicles. They rely on a signal from the smart key to activate your ignition

Try holding the low battery fob key directly against the start button so it can detect the signal. Some push start vehicles might even have a slot on the dash, steering column, or console where you can insert the fob key to start your car. Check your owners manual to find out.   

Are there other key fob questions rattling around in your brain? 
Let’s get to them. 

4 Other Key Fob FAQs

Here are the answers to some frequently asked questions about key fobs: 

1. What Type of Batteries Do Fobs Need?

Key fobs usually use a 3V button cell CR2032 battery. Your fob might also use CR2016, CR1616, CR2025, and CR2450. 

2. How Much Does Replacing Fob Batteries Cost?  

This is an easy DIY job, so you’ll only have to buy the replacement battery for your remote key fob. The replacement battery can cost approximately $6-7, depending on the brand and amount of batteries you buy.

For example, an Energizer original battery pack of two costs around $6, while a Panasonic original battery pack of four costs $7. You can easily purchase the battery packs at Walmart — no need to go to a service center. 

3. How Long Do Fob Batteries Last?

The battery life depends on whether you’ve got a regular remote key fob or a smart key.

A smart key fob battery can last up to 2 to 3 years. A regular fob battery can last around 4 to 6 years. There are signs pointing to a low fob battery you should notice.  

4. What’s the Difference Between a Smart Key and a Key Fob?

A key fob has respective buttons, to lock or unlock your vehicle or to open your boot. A smart key fob uses radio pulses to lock and unlock your vehicle, allowing keyless entry. Sensors on your vehicle pick up the signal when the car key is close enough and activate keyless entry. 

Modern push-start vehicles also use this technology to start the ignition, allowing for a button start. Your car must register the smart key in proximity for the remote start to work. 

Final Thoughts

Something as simple as a low fob battery can cause a lot of inconvenience. Your dashboard lights, like the low battery light, can help you deal with minor issues before they become a big problem. 

Need some help diagnosing various dashboard lights? 
Call AutoNation Mobile Service today. 

Our qualified mobile mechanics will come straight to your driveway and fix any car issues you’re facing. Whether it’s a car key replacement or fixing a car door problem, all AutoNation Mobile Service repairs come with a 12,000-mile/12-month warranty. 

Use our convenient online booking services to schedule a mechanic visit easily.