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Can You Drive a Keyless Car Without the Key? What Happens If You Drive Without the Key?

Car owner unlocking their car with their key fob.

Life these days is all about convenience. Regarding the automotive industry, car manufacturers provide this convenience by making driving as seamless as possible.

Let's take the example of push-button cars. These keyless cars ditch the hassle of manual ignition in favor of a push-button start—no need to insert and turn a metal key. Instead, press the "start/stop" button, and the keyless ignition will fire up. But there is a catch: you need to have your key fob close by so the car can detect it.

But what happens if the key fob dies? Or worse, you lose it? Can you drive a keyless car without the key? Let's find out.

Yes, you can drive a keyless car without the key, as long as the car is unlocked and the engine is already running. The car will notify you that the key fob is missing, but you can drive it until you reach a safe place.

Driving a keyless car without its key will be difficult if the engine is off.

So what happens when you drive away with your key fob behind? Let's learn!

Table Of Contents [show]

    Car owner unlocking their car with their key fob.
    Car owner unlocking their car with their key fob.

    Can a Push-Button Car Start Without the Key?

    No, a push-button car cannot start without the key. The key fob is the only way to communicate with a keyless car. You will need the fob to unlock or start the engine.

    Hotwiring is also not an option because the keyless ignition system in these cars is much more sophisticated.

    Before we explain why you can't start a keyless car without the key, let's look at how the key fob in push-button cars works.

    The key fob in a keyless car is a wireless transmitter in the form of a remote control.

    Pressing the key fob button signals the car to unlock/lock the doors, opening the trunk, and starting it.

    These transmitters are fed a unique ID tag that links them to different cars.

    Each keyless car identifies its ID tag and unlocks and triggers the keyless ignition only when it senses the correct key fob nearby.

    With it, you can start your vehicle or unlock it, for that matter. Instead, you will have to tow your car or ask a friend to bring you your key.

    If the car is already running, you can drive it even if the key fob is left behind. But once the engine stops, you will need it to restart the car.

    A BMW started by its key fob.
    A BMW started by its key fob.

    How Long Will a Car Stay Running Without the Key Fob?

    Without the key fob, a car will stay running until you turn it off or until it runs out of gas. If you don't cut the engine and keep filling the tank, it will go on and on.

    A keyless car needs its key for unlocking/locking the doors and starting the engine. So if you lose the key after unlocking and starting the car, you can continue to drive it. But once you switch it off, there is no easy way to restart it without the key.

    If you don't turn the engine off, the car will stay running until the fuel tank runs out. And, if you refill it before the engine dies, the car will keep running.

    What Happens When You Drive Away Without the Key Fob?

    When you drive away without the key fob in the cabin, the car will beep to alert you about its absence. It won't turn off, so you can keep driving until you reach a safe spot to park your car.

    There is a rumor that keyless cars cannot drive without them. Or that they stop automatically if the key fob is out of range. That is not true. Imagine having yours dying on you in the middle of the highway. It would create a dangerous situation for you and the other drivers.

    Car manufacturers realize how easy it is to lose a key fob or forget to replace its battery. That's why they have programmed the car to stay running if the key is not detected after the engine has ignited.

    Once it fails to detect the key, your car will send out warning signals to inform you that it is missing.

    For example, it might beep or display alerts at regular intervals so you can urgently drive the car back to retrieve your key or to get a new one.

    A car can drive far without key fob.
    A car can drive far without key fob.

    How Far Can I Drive My Car Without My Key Fob?

    Once the engine has started, there is no limit to how far you can drive your car without your key fob. You can drive it as far as your fuel tank can take you. The car will not stop until it runs out of fuel, so you can go as far as you want.

    The operable range of most key fobs is 20 to 50 feet. At this distance, you can use it to open the trunk and lock/unlock the doors.

    If the fob is within the operable range, you can slide in to start the keyless ignition with the car unlocked.

    Once the engine is running, you no longer need to have the key with you. You can pull away, albeit the beeping and warnings, and drive as far away as you want until you arrive at your destination and turn the car off. Now you need the key on you to turn it back on.

    But what if you don't turn it off?

    If you don't switch it off at any point, your car will travel as far as the fuel in your tank will allow.

    Conclusion

    Key fobs are fun car technology. They let you operate a car more conveniently and are safer for drivers with motion disabilities.

    Always ensure your key is with you before entering and exiting the vehicle. You cannot start a keyless car without the key. However, you can drive it once the engine has fired up with the key within operating range.

    After that, there is no limit to how long and far the keyless car will run unless you turn it off.

    For safety purposes, you should always lock the car after you have stepped out. Otherwise, anyone can obtain a keyless entry, trigger the keyless ignition, and drive away while you are close by.