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Summary
  • A vehicle with a keyless entry system is locked and unlocked using a small electronic device called a key fob.
  • If the key fob’s LED light doesn’t turn on, has bad signal strength, and needs multiple clicks to work, then it most likely has a dead battery.
  • Even if your key fob isn’t working, you can still start your car by using the emergency blade that usually comes with the fob.

A key fob can make locking and starting your car fast and easy, especially when you have your hands full. However, it can also become inconvenient when its battery starts to go bad. It’s best to learn about the different symptoms of a dead key fob battery you can look out for.

What Is a Key Fob Battery?

A vehicle with a keyless entry system is locked and unlocked using a small electronic device called a key fob . It has a short-range radio transmitter that sends distinct codes to a receiver in the vehicle.

key fob for a 2006 ford explorer
This fob is for a 2006 Ford Explorer and has the kind of button battery usually found in remote key fobs. | Image Source: Richard McCuistian

A key fob battery powers the electronic circuits within the fob. Most car manufacturers use non-rechargeable button cell batteries, which are small round lithium batteries commonly used in watches, thermometers, and calculators. Because the key fob relies on its battery to function properly, it’s important to know when to replace it.

How Do I Know If My Key Fob Battery is Dead?

Diagnosing a dead key fob battery doesn’t have to be hard. Here are some signs you can watch for:

LED Light Doesn’t Turn On

Key fobs once came with a small LED light that would illuminate when the fob is activated, but most key fobs since the early 2000s don’t have this feature.

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If the key fob does have the small LED light that turns on every time you click a button, just look at that LED when you press the button.

Key fobs once came with a small LED light that would illuminate when the fob is activated, but most key fobs since the early 2000s don’t have this feature.

– Richard McCuistian, ASE Certified Master Automobile Technician

One obvious way to tell if the key fob battery is low or dying is when the LED doesn’t light up.

If the LED light turns faint or stops lighting up, then this is likely a sign of a dead key fob battery.

, Dead Key Fob Battery Symptoms and FAQ

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: You can sometimes simply clean the battery contacts with a new pencil eraser and clean the battery the same way. Sometimes, this will bring the fob back online, but usually the battery needs to be replaced if the fob gets weak or inoperative.

Bad Signal Strength

Most key fobs have a signal range of 30 to 60 feet, so you can unlock your car with ease even if you’re still across the parking lot. However, if you notice you have to stand closer and closer to your car for the doors to unlock, then this might be a sign of a dying key fob battery. A dying key fob battery causes the transmitter to lose its range, limiting your distance from the car when using it.

Key Fob Needs Multiple Clicks to Work

One of the symptoms of low battery in your key fob is needing multiple clicks for it to work. A key fob with a working battery should only need a single click to work. If you have to click two or more times to make sure it locked or unlocked your vehicle, then it might be time for a battery replacement.

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Delays in Locking and Unlocking

If there are delays in locking and unlocking your car, then this can be a sign of a dying key fob battery. A one to two-second delay might not seem like a big deal at first, but it can be quite inconvenient down the line. As a preventive measure, consider having your key fob checked immediately.

Key Fob Battery FAQ

Can a Dead Key Fob Stop Your Car From Starting?

Even if your key fob isn’t working, you can still start your car by using the emergency blade that usually comes with the fob. An emergency blade, or E-blade, is a mechanical key inside the fob that you can access by unlocking the fob cover. You can use it like a traditional key to start your vehicle.

Depending on the car model, the key fob can also contain a security chip that will work even without a battery. To use it, however, you need to hold it close to the ignition button or insert it into a slot to start your car. If you aren’t sure which emergency measure applies to your vehicle, you can check your owner’s manual for more information.

What Is the Average Life of a Key Fob Battery?

A regular key fob battery typically lasts for four to six years, while a smart key fob usually lasts for two to three years. A smart key fob has a receiver that has to communicate often with the car, which drains its battery much faster.

Can You Replace the Key Fob Battery Yourself?

Most car manufacturers make it easy to replace the battery with just a small screwdriver in hand, so if you want to save on labor fees, you can try replacing it yourself. Just be sure to get the correct battery type.

Most car manufacturers use CR2032 3-Volt batteries. Other common types include the CR2025, CR2016, and CR1616. If you aren’t sure what your key fob uses, you can simply check the old battery, which should come with a printed identification number.

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Get a New Key Fob Battery Delivered to Your Home

If the key fob battery drains and dies, you might want to stop taking your car or truck out for a drive until you get a replacement battery. It’s best to avoid issues like getting no response when wirelessly locking or unlocking the doors, or engaging or disengaging the locks at the wrong time. Fortunately, you can order a new key fob battery from CarParts.com, which ships replacement parts where you need them.

CarParts.com delivers affordable, reliable key fob batteries and other parts and accessories to your doorstep. We operate several distribution centers in strategic locations across the US, which helps reduce delivery times. The nearest center processes your order using the latest technology before shipping your new part to your address. You don’t have to wait more than several business days for your replacement part to arrive if you live in the continental US and place your order before 12 p.m. ET. Furthermore, we guarantee the reliability and performance of our key fob batteries by exclusively sourcing our parts from trusted manufacturers.

When it’s time to replace the key fob’s depleted battery, turn to CarParts.com. Order one of our key fob batteries today and enjoy quick delivery of replacement parts!

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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