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
Sep 22, 2016

Few modern cars require you to use a mechanical key to unlock the doors. Instead, most locks can be operated by remote control. You point the key at the car, and press it to unlock the doors.

Full keyless entry doesn't require any button-pushing. Just having the key fob in your pocket is enough to unlock the doors.

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 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

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