What is keyless entry?

Doors that open with the brush of a hand, bootlids that lift with a wave of your foot: how keyless entry works

BuyaCar team
May 18, 2018

Keyless entry systems hope to eradicate the boring and frustrating search for keys tucked away in rucksacks and handbags.

No modern cars require you to unlock your door by physically turning a lock any more - and a fully keyless system doesn't even require any button-pushing.

Just having the key fob in your pocket is enough to unlock the doors, keeping your hands free to put valuable items securely in the car.

Once inside, you can simply press a button to start the engine, if the car has keyless start-stop as well.

How does keyless entry work?

Keyless fobs contain identity chips that are constantly listening out for radio signals broadcast by their car. The radio signals can only travel short distances - typically less than five metres.

When you put your hand on the door handle of a keyless car (in some cases you have to press a button), the car sends out the short radio signal.

If the fob is in range, it's then triggered to respond to the car, sending out its own code. The car recognises this and unlocks the doors.

The process is similar to start the car with a button and systems are usually advanced enough that they will only start the car if the key fob is inside.

Increasingly, there are keyless boot opening systems, like the one on the BMW 3-Series below, with sensors on the back bumper. Waggle your foot underneath the bumper and the boot will open automatically, without you having to touch the handle - handy if your hands are full.

What are the problems with keyless entry?

Your car doesn't automatically switch off the engine and lock itself if the fob goes out of range. This is to ensure that you're not suddenly stranded in the middle of the motorway if its battery dies.

However, this also means that you could drop someone off who has the keyfob in their bag or pocket and then drive away. As soon as you turn the engine off, you won't be able to start the car again.

There are also serious concerns about the security of keyless entry systems, with a number of ways that thieves are able to breach them. In 2011, researchers from Zurich showed how the radio signals emitted by cars could be boosted, tricking it into thinking the keyfob was nearby. Police have investigated criminals who block the signals from keyless devices, so that car doors never lock, and there are also allegations that thieves can intercept the codes that are transmitted between keyfob and car.

In 2014, after a spate of Range Rover thefts, police advised owners to fit a steering wheel lock as a second line of defence against thieves who were able to overcome keyless security. Land Rover subsequently issued a fix for their cars.

Security experts recommend that you keep keyless entry keys away from doors and windows, and in a shielded protection case, as thieves can steal the signal to replicate your key wirelessly, from outside of your house.

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