Keyless Car Theft & Relay Attacks: How to Stop Them
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Quick answer
A relay attack uses two thieves and a signal relay: one stands near your front door boosting your key fob's signal, the other stands by your car, which thinks the key is beside it — so it unlocks and starts. The car never needs your actual key. The defence is simple: block the signal. Keep fobs in a faraday pouch or metal box at home, away from the front door, and your car can't be relayed.
How a relay attack works
Your keyless fob constantly emits a short-range signal, waiting for the car to ask for it. Thieves use a relay device to capture that signal near your house and transmit it to a second device held next to your car. The car receives a valid-looking key signal and unlocks; the thief gets in, presses start, and drives away. The whole thing takes under a minute and leaves no damage — which is why victims often don't realise until morning.
Which cars are at risk
Any car with keyless entry and push-button start is theoretically vulnerable, though some newer models have motion-sensor fobs that sleep when stationary. If your fob doesn't sleep, your car is a candidate. High-value and commonly targeted models get hit most, but relay theft is opportunistic — thieves walk streets at night trying door handles of anything that unlocks.
Practical defences that work
These are cheap and effective:
- Faraday pouch for every fob — test it by trying to unlock the car with the pouch closed
- At night, keys in the pouch, stored away from the front door and windows
- A steering-wheel lock as a visible deterrent — thieves want the easy car
- Park in a garage or well-lit spot where a driveway box or camera is visible
- Ask your dealer whether keyless entry can be disabled on your model — many allow it
What to do if it happens
Call the police first and report the theft, then your insurer. If the car is recovered — relay-stolen cars sometimes are, dumped after a joyride — have the keys checked: the thieves may have cloned or added a key, so a security check and possibly erasing unknown keys from the immobiliser is sensible. We can check which keys your car recognises and remove any that shouldn't be there.
What we won't do
A note on honesty: we don't supply or fit aftermarket security systems like Ghost immobilisers. If you want that kind of protection, talk to a specialist installer. What we can do is diagnose key and immobiliser issues, code and erase keys, and give straight advice.
Related questions
Does a faraday pouch really stop relay theft?
Yes — it blocks the fob's signal, so there's nothing for thieves to relay. Test yours: put the fob in, close it, and try to unlock the car. If the car stays locked, the pouch works.
Will my car alarm stop a relay attack?
No — the car thinks a valid key is present, so it unlocks and disarms normally. The alarm never triggers because, as far as the car knows, nothing is wrong.
Should I keep my keys in the fridge or microwave?
It can work as a makeshift faraday cage, but it's awkward and risky (microwaves get switched on). A proper faraday pouch costs little and does the job properly.
Need a locksmith, not just a guide?
Call 07425 435697 — open 24/7 across Birmingham. Tell us the make and model and we'll give you an honest price before we set off.
Open 24/7 — nights, weekends and bank holidays included.