How Long Do CR2032 Batteries Last In A Key Fob?

If you're old enough to remember when cars had simple key ignition switches and not start buttons, you may find modern key fobs frustrating. With your key in hand, the only dead battery that could leave you stranded was the one in your vehicle. Modern key fobs, which do a lot more than unlock your vehicle, can also leave you stranded. Inside that little device is a button cell battery, often a CR2032 type. If that battery dies, you may be left standing in your garage, frustrated and late for work.

Key fobs have evolved from a simple way to lock and unlock your car. Many offer other functions, allowing you to open the trunk or back gate, lower your windows, and remotely start the car. Modern key fobs also talk to your car's security system, transmitting a code that disables the immobilizer system and allows your car to start. So what happens if the battery in your key fob dies?

Luckily, key fobs typically drain batteries very slowly, and a CR2032 battery should last several years, perhaps up to five. Its life will partly depend on how often you use the fob, exposure to extreme temperatures, or a damaged or malfunctioning fob. Your key fob may require a bit more maintenance and care than a simple car key, but it also offers convenience that's hard to beat.

If you've owned your car long enough that the new car smell has worn off and or you bought your car pre-loved, you may worry that your fob may soon need a new battery. Luckily, there are several ways to tell. The first is the easiest, and doesn't even require that you pay much attention. Some car apps, including KiaConnect and the Toyota app, will alert you if the battery is getting low, though be aware that this feature is not universal and may require a paid subscription. Similarly, however, you may receive a notification on your vehicle's dashboard that your fob battery needs to be replaced.

You may also notice that the range of the key fob has decreased and your vehicle won't unlock or lock unless you're standing very close. Sometimes the fob loses sensitivity, and the buttons may be unresponsive or working intermittently. These are all signs of a dying battery. 

Once you know the fob needs attention, check your vehicle's manual if you're unsure how to get it open to swap the old battery for a fresh one. If you're out and about and the fob suddenly dies, don't panic. Most cars will still start if you simply press the fob up against the ignition button, and some automakers even hide a physical key inside the fob that you can use to gain access to your vehicle or start the engine. CR2032 batteries are readily available, and if you're worried, keep one on hand in case your fob dies unexpectedly.