This question came about because our reader wanted to know whether they should buy a Faraday pouch. These block the signals emitted by keyfobs to keep cars safer. The reader has a car where you press the button on the keyfob to unlock the door. But to start their car, you just have to press a start/stop button on the dash, provided the key is in the car.
What is a keyless car?
Back in the day, you used to enter your car by putting your key into the door lock, like at your front door. You would then put the key into another lock, in the form of the ignition to start the engine.
Keyless technology changed that. Rather than a physical key, the unlocking is done by radio signals. These bounce between the car and its key fob. A car is now considered keyless if you can either unlock it, start it, or do both, without touching the key.
But there are some cars, like our reader’s, where you unlock it by pressing a button on the keyfob. You then just have to press a button in the car to start the engine.
This is keyless start and is more common – particularly in slightly older or cheaper models – than the more modern (and expensive) keyless entry and start.
How do keyless cars work?
Keyless technology works by the car sending out short-range radio signals and the keyfob picking these up. When the keyfob communicates back to the car, the car unlocks. The keyfob then tells the car it is present inside the vehicle, the immobiliser disengages and the engine will start.
When do you need a Faraday pouch?
A Faraday pouch blocks the signals between the car and key. This prevents anyone ‘grabbing’ the signal when the keyfob isn’t in the car and opening the car illegally. In an ideal world, you need a Faraday pouch when a car is both keyless entry and start.
If a car is just keyless start do you need a Faraday pouch?
The reason you have a Faraday pouch is to stop the criminal lowlife performing what’s known as ‘relay theft’. This is when they take the signal emitted from the key and use a secondary device to bounce it to the car. This fools the car into thinking the key is present and that it should unlock and start.
But if a car doesn’t have keyless entry, the reasons to have a Faraday pouch are far fewer. The thief will have to use a much cruder method to unlock the car – assuming they haven’t nicked the keyfob. Once they’ve unlocked it (or smashed a window), they can in theory take advantage of the keyless system’s vulnerabilities to start the engine.
If someone is going equipped to perform a relay theft, they’re unlikely to want to break into the car. This will possibly damage it and may well set the alarm off. And once, they’ve done that, they’ll have to get busy with their computer gear. All of which increases the likelihood of getting caught.
I’ve been writing about cars and motoring for more than 25 years. My career started on a long-departed classic car weekly magazine called AutoClassic. I’ve since pitched up at Autosport, Auto Express, the News of the World, Sunday Times and most recently the Daily Telegraph. When I’m not writing about cars and motoring, I’m probably doing some kind of sport or working in my garden.
