Keyless Go Theft: How Relay Attacks Work and How to Stop Them
TOCA · KNOWLEDGE
By TOCA Editorial · 2026 · 6 min read
Your car is locked. Your keys are inside your house. And someone drives away in it in under 60 seconds. This is not a hypothetical scenario. It happens every day and your keyless entry system is the reason.
What is a relay attack?
A relay attack is a method car thieves use to exploit the way keyless entry systems work. Your car key continuously emits a weak radio signal. As soon as your vehicle detects that signal nearby, it unlocks. Practical, convenient and exploitable.
Two thieves work together. One stands outside your home, close to the front door or a window. The other stands next to your car on the street. The first thief uses a relay amplifier to pick up the faint signal from your key inside the house and boost it. The second thief's device receives that boosted signal and transmits it directly to your vehicle. The car receives what it thinks is your key right beside it, and unlocks.
The entire process takes less than 60 seconds. No broken window. No alarm. No trace.
"No broken window. No alarm. No trace. The entire process takes less than 60 seconds."
Which vehicles are affected?
Any vehicle with a passive keyless entry system, meaning one that unlocks automatically when the key is nearby without pressing a button, is potentially vulnerable. This includes vehicles from BMW, Mercedes, Audi, Volkswagen, Toyota, Ford and most other major manufacturers produced in the last 15 years.
A 2023 ADAC study found that the vast majority of keyless vehicles tested were still susceptible to relay attacks, including newer models. The technology that creates convenience also creates the vulnerability.
Why locking your car is not enough
A common misconception is that properly locking your car provides sufficient protection. It does not. The attack happens before the car is even selected as a target. Thieves scan residential areas for active key signals. If your key is near the front door, in the hallway or next to a ground-floor window, the signal can be captured through the wall.
"The vehicle is not the weak point. The key is."
How to effectively protect your vehicle
There are several approaches, from free habits to physical products. Not all are equally effective.
Store your key in a signal-blocking pouch
This is the most reliable and practical solution. A Faraday pouch, a small sleeve lined with conductive shielding material, completely blocks your key's radio signal when it is correctly sealed inside. No signal means no relay attack is possible.
The key word is "correctly sealed". A loosely folded pouch or one with a damaged seal does not provide reliable protection. Look for pouches with a roll-top or fold-seal closure system. Test your pouch by placing the key inside, sealing it, then walking to your car. If it does not open, the pouch is working.
Keep your key away from doors and windows
If you do not have a Faraday pouch, store your key at least in the centre of your home, well away from exterior walls. The further the key is from outside, the weaker the signal thieves can capture. This is not a secure solution, relay amplifiers are powerful, but it reduces the risk.
Disable the keyless function
Some manufacturers allow you to disable the passive proximity function, so the vehicle only responds when the button on the key is physically pressed. Check your vehicle manual or contact your dealer. This eliminates the relay attack vulnerability entirely, though at the cost of convenience.
What about when you are out and about?
Most advice focuses on protection at home. But relay attacks also happen in everyday situations, in shopping centres, car parks, restaurants and anywhere people carry their keys in a bag or jacket pocket.
If your key is in your jacket pocket while you are sitting in a café, someone with a relay amplifier can capture the signal and pass it to a partner waiting outside next to your car.
"Most people protect their keys at home. Hardly anyone thinks about what happens on the go."
This is where a compact signal-blocking sleeve for everyday carry becomes relevant, not just something kept by the door at home. A slim sleeve that fits in a bag or jacket pocket provides the same protection on the go.
How to test your Faraday pouch
Not all signal-blocking products on the market perform equally. Some cheap pouches attenuate the signal rather than blocking it completely. Here is how to test yours:
- Place the key in the pouch and seal it correctly
- Walk to your car and try to open it. It should not respond.
- Press the unlock button on the key while it is inside the pouch. The vehicle should not respond.
If your vehicle responds to either test, the pouch is not blocking effectively. A correctly functioning Faraday pouch completely isolates the key from all external signals.
The practical reality
Relay attacks are not theoretical. Insurance companies across Europe and the US are recording significant increases in keyless vehicle theft. Authorities including the Metropolitan Police, West Yorkshire Police and the German ADAC recommend signal-blocking pouches as the most practical countermeasure available to drivers.
Keyless entry technology was not designed with this attack vector in mind. Until manufacturers implement more robust solutions, such as ultra-wideband (UWB) positioning or motion-sensing keys that go to sleep in a pocket, the responsibility for protection falls to the driver.
"The simplest protection works at the source: block the signal before it can be captured."
TOCA produces and designs signal-blocking sleeves and bags for car keys, smartphones and other devices. DEKRA certified. Designed in Germany. Built for everyday use. Find out more.