What to Do When Your Smart Key Battery Dies: How to Unlock and Start Your Car

July 2, 2025

You’ve just taken an exit off the Bruce Highway and you’re grabbing a coffee and a hot pie to keep you fuelled up for the rest of the journey. Everything is going just as planned until you get back to your car and your key fob is dead. You press it—nothing. You’re locked out of your car and you’re stranded at a servo. What do you do next? How do you unlock your car and get back on the road? Do you need to call an auto locksmith?

We’re about to share some info on what you need to do to unlock car when key battery dies.

Warning Signs of Smart Key Battery Dying

Prior to a smart key battery dying, you will often see some warning signs. Initially, you may notice that the distance from which your smart key can unlock your car is reduced when the remote buttons are pressed. Another sign of coming battery failure is when your smart key’s performance becomes inconsistent. At times, it might unlock your vehicle right away and yet in other instances it could take a couple of tries to get it to work.

In more modern cars, you may see a dashboard warning or an alert that lets you know the battery on your smart key is low. This message may appear when you start your engine. Older keyless systems, however, might not show this specific warning, making it even more important to pay attention to other warning signs.

Tips to Unlock Car When Key Battery Dies

In Australia, smart keys are a standard component on many modern vehicles. Designed to communicate wirelessly, these devices let a driver unlock their car or ute without having to take the smart key out of their bag or pocket. They won’t be able to communicate wirelessly when the battery fails. Fortunately, it’s still possible to access your car if the smart key battery is dead.

All smart keys come with a mechanical key hidden inside the fob called the ’Emergency Key’ or ’Emergency Blade’. This may be accessed via a latch or small release button on the smart key fob. The emergency key can be used to mechanically open the driver’s door using the keyhole on or near the handle. Often the keyhole is hidden by a small, liftable portion of the handle itself, and can be the same colour as your car. You may need to use the key as a lever to gently lift it off an expose the keyhole. Look closely – it’s there somewhere! Certain car models may even offer an option for a keyless entry system code that can be used wuth your mobile phone to unlock or lock the doors if the fob battery dies.

Starting Your Car When the Smart Key Battery Dies

If your smart key battery fails, you’ll also need a way to start your car. The good news is that your smart key WILL still be able to start your car. The smart key needs to be close enough to the car’s security aerial to register the presence of the key. With a dead key batter, the key no longer ’projects’ the signal from your pocket or handbag as it normally would. For many brands of vehicle the aerial is located in a circle around the ’Start Engine’ button. So you can use the fob itself to push the Start Button with your foot on the brake pedal as usual, to start the car. Some brands of cars have different spots within reach of the driver’s seat where the aerial is located. Some will have a small picture of a key on the lining below the steering wheel, others may have a spot inside the drink holder in the centre console. For these cars, hold the smart key fob against the key symbol, place your foot on the brake and hit the Start button.

If your car or ute has a smart key, you’ll want to recognise warning signs so you’ll know your smart key battery is about to fail. It’s also important to know how you can still unlock your car and start your engine if smart key fob isn’t working.

Knowing what to do, and keeping a spare key battery available, can save you trouble and continue on your journey. For more information, visit Northside Car Keys.