Keyless entry is wonderfully convenient - walk up, the car unlocks, push a button, drive off. The flip side is relay theft, a quiet, fast technique that can steal a keyless car from a driveway in seconds, often without a sound. The good news is the defences are mostly cheap and simple. Here's how relay theft works and what genuinely helps.
How a relay attack works
Your keyless fob is always listening for the car. When it's close enough, it answers, and the car unlocks and allows a start. A relay attack exploits this: one thief stands near your house with a receiver that picks up the fob's signal, then relays it to a second device held by an accomplice next to the car. The car thinks the key is right there and unlocks. The whole thing can take seconds and leave no broken glass.
It works because the fob's signal reaches through walls and doors. The trick is to stop the signal reaching a receiver in the first place.
Free habits that help
Keep your keyless fob well away from the front of the house and the car - the further inside, the better, so the signal can't be picked up from outside. Don't hang keys by the door or on a hall console; that's the easiest place for a receiver to reach. Some fobs can be set to a sleep or off mode that stops them transmitting when not in use - check your handbook, as not all fobs have it, but it's worth knowing.
Low-cost tools
A Faraday pouch or box blocks the fob's signal entirely when the key is inside it. They're inexpensive and effective - the signal can't get out, so a relay attack can't pick it up. Keep one by the door for your everyday keys, and store spares in one too. A steering wheel lock is an old-fashioned but visible deterrent that adds a physical barrier the relay trick can't bypass, and some insurers like seeing one.
What doesn't help (much)
Hiding the fob in a metal tin can work, but it's unreliable - not all tins block the signal fully, and it depends on the tin. A proper Faraday pouch, tested by locking the car with the key inside it, is the dependable version of the same idea. Removing the battery overnight isn't practical for daily use, though it would of course stop the signal.
If the worst happens
If your keyless car is stolen, the fob may still be in your house - which is exactly how relay theft works, and a sign of how it happened. Report it immediately. If you suspect your fob's signal has been compromised or a key is missing, a locksmith can erase the compromised key from the car's memory and code a fresh one so the old fob can no longer start it.
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Quick questions
Do Faraday pouches really work?
Yes, when used properly. A good Faraday pouch blocks the fob's signal so a relay receiver can't pick it up. Test yours by putting the fob inside and trying to unlock the car - if it doesn't unlock, the pouch is working.
Can a locksmith help after a relay theft attempt?
Yes. We can erase a compromised fob from the car's memory and code a fresh one so the old key can no longer start the vehicle - the key side of securing the car after an attempt.