What Happens if My Key Fob Battery Dies?

If your key fob battery dies, the fob will stop communicating with your vehicle or access system until the battery is replaced. This means you may not be able to unlock your car, open a gated entrance, or start your vehicle with the key fob until power is restored.

Understanding what happens and how to prepare can keep you from getting stranded or locked out.

Why Key Fob Batteries Die

Key fobs use small coin-cell batteries (often CR2032 or similar) to power the radio-frequency communication that tells your vehicle or access control system to unlock or start.

Several factors can influence how long a key fob battery lasts:

• Frequency of use — more button presses drain power faster
• Temperature extremes — heat and cold can reduce battery life
• Fob age — older fobs may draw current less efficiently

According to industry estimates, key fob batteries typically last between 3–5 years under normal use.

“Battery issues are one of the most common reasons customers contact us when their fob stops working,”  - KeyMe Locksmiths

What Happens When the Battery Dies?

When a key fob battery dies:

1. The Fob Won’t Communicate Wirelessly

Your car or access system may no longer respond when you press buttons.

• Doors may not unlock with the remote button
• The vehicle may not detect the fob for push-button start
• Access panels may not register the fob signal

This happens because the radio signal that your fob sends requires battery power to function.

2. Backup Methods May Be Available

Many systems are designed with low-power or mechanical backups. These typically include:

• A physical key blade inside the fob
• Touch-to-start or NFC backup modes in newer vehicles

These methods provide alternate access but may still require a working battery for full functionality.

“Even with a dead battery, many vehicles allow physical entry and starting methods that act as backups,”  - KeyMe Locksmiths

3. Some Systems Alert You Ahead of Time

Many modern cars and access systems provide low-battery alerts weeks before full failure. These reminders help you replace the battery before the fob stops working.

How Long You Can Go with a Dead Battery

There’s no universal cutoff, but once the battery is fully discharged, the fob will stop responding. It won’t damage the fob, but normal wireless functions will not work until the battery is replaced.

According to auto industry battery data, a dead key fob battery typically leaves the fob inoperable until a fresh battery is installed, there’s no built-in reserve once power is gone.

How to Replace Your Key Fob Battery (High-Level)

Replacing a dead key fob battery usually involves opening the fob’s case and inserting a fresh coin-cell battery. Due to variations in fob design, procedures differ between manufacturers.

KeyMe offers key fob battery replacement services when self-replacement isn’t convenient or possible.

“Battery replacement is a routine part of key fob maintenance, having a fresh battery on hand can save time and inconvenience.” - KeyMe Locksmiths

Why It’s Smart to Monitor Your Fob Battery

Keeping your key fob battery healthy can help you:

• Avoid being locked out of your car or property
• Prevent unexpected no-start situations
• Maintain full remote convenience features
• Reduce wear on mechanical locks from repeated manual use

Data from automotive service studies show that routine fob battery replacement is one of the top preventive maintenance tasks recommended by vehicle technicians.²

Frequently Asked Questions

How long does a key fob battery last?
Most key fob batteries last about 3–5 years with typical use.¹

Will my vehicle still start if the fob battery dies?
Many vehicles allow backup methods, such as physical key blades or touch-to-start features, but these vary by make and model.

Can a fob be damaged by a dead battery?
A dead battery won’t harm the fob, but normal remote functions won’t work until the battery is replaced.

How can I tell if my fob battery is low?
Many modern vehicles alert you with dashboard messages or reduced range before the battery dies completely.

Can KeyMe replace my key fob battery?
Yes, KeyMe offers professional key fob battery replacement services where self-replacement isn’t feasible.

Keep Your Fob Powered

If your key fob stops responding, a dead battery may be the simplest explanation. Checking and replacing the battery before it fails can save time and frustration.

Find Key Fob Battery Replacement Services or Explore KeyMe Fob Options

KeyMe Locksmiths — Practical Access Solutions You Can Rely On

About KeyMe Locksmiths

KeyMe Locksmiths is a leading provider of local locksmith services and key copy kiosks across 50 states and the District of Columbia. Proud to serve over 5 million customers, KeyMe Locksmiths cuts over 10 million keys annually. With more than 7,500 self-service kiosks in major retailers, an e-commerce platform delivering over 10,000 keys weekly, and a nationwide locksmith network, KeyMe Locksmiths provides fast, reliable solutions for residential, commercial, and vehicle needs. KeyMe Locksmiths is committed to delivering exceptional service backed by a 100% money-back guarantee. KeyMe Locksmiths also operates one of the