They show up at your driveway in seconds: thieves use cheap signal-boosting gadgets to make a car think its key fob is nearby, then unlock and start the vehicle. You can stop this by keeping key fobs in a signal-blocking pouch and changing habits that leave keys near doors or windows.
This piece explains how those relay attacks work, why certain cars remain vulnerable, and what practical steps to take now to protect a vehicle and its keys. Expect clear, no-nonsense tips on simple products and behavioral changes that cut the theft risk.
Understanding Keyless Entry Relay Attacks
These attacks let thieves open and start cars without physical keys by capturing and relaying the key fob’s radio signal. Drivers should know how criminals do it, why newer cars are vulnerable, and what signs indicate targeting.
How Relay Attacks Work
A pair of attackers use two compact wireless devices. One stands by the vehicle and the other moves near the house or pocket where the key fob sits.
The device near the key amplifies or repeats the fob’s signal to the device by the car, which tricks the vehicle into thinking the fob is present.
Once the car accepts the relayed signal it will unlock and allow engine start in push-button systems. Thieves often perform the operation in under a minute, then drive away.
Physical locking or alarms don’t stop the signal relay; the attack exploits radio communications, not mechanical access.
Why Modern Vehicles Are at Risk
Keyless entry and push-button start rely on low-power radio exchanges that assume proximity. Manufacturers prioritized convenience, so many systems respond to a weak signal without strict distance validation.
Cars with passive entry and no secondary authentication are the most exposed.
Aftermarket key fobs, spare keys left at home, and dealer-programmed spare keys increase risk because multiple functioning transmitters widen the attack surface.
Some manufacturers offer signal-disable options or firmware updates; drivers should check dealer guidance and security bulletins like those from local auto-security advisories (for example, see guidance on protecting vehicles from relay attacks: https://jactautosecurity.co.uk/blogs/news/protecting-your-vehicle-from-keyless-entry-relay-attacks).
Common Signs Your Car Might Be Targeted
Unexplained unlock attempts or lights flashing when no one uses the key fob can indicate a relay probe.
Neighbors reporting suspicious individuals loitering near homes or vehicles is another red flag.
If a car is stolen without forced entry, relay theft is a plausible cause.
Repeated attempts to lock or unlock remotely, or finding the key fob drained faster than normal, can also suggest someone is attempting to capture or stimulate its signal.
How to Prevent Keyless Entry Car Theft
Keep keys out of range, add physical locks or signal-blocking pouches, and consider electronic or mechanical aftermarket barriers that interrupt thief access to the vehicle’s systems.
Practical Tips for Securing Your Vehicle
They should store key fobs in a Faraday pouch or metal container when at home to stop relay devices from amplifying the fob signal. Placing keys away from doors, windows, and letterboxes reduces the chance a thief captures the signal through the front of the house.
They should disable passive unlock if the car allows it, or use the manual lock button on the fob. When parking, they should choose well-lit areas and lock the steering column or wheel with a visible device as a deterrent.
Keep spare keys off the property and reprogram keys after buying a used car. Regularly check software and recall notices from the manufacturer for patches that close remote-attack vectors.
Best Devices and Upgrades for Protection
They should buy a certified Faraday pouch sized for the specific fob; low-cost sleeves often work, but test by attempting to unlock the car while the fob is inside. RFID-blocking key fob covers sold online offer practical shielding for most keyless systems.
They should install a visible steering wheel lock and consider an aftermarket immobiliser that cuts starter or fuel power. For vehicles that support it, a manufacturer-approved software update or dealer-installed security module often strengthens authentication.
They should opt for aftermarket alarm systems with tilt, glass-break, and motion sensors, plus tracking services that alert if the car moves. Prioritize devices with independent verification or good user reviews rather than unbranded knockoffs.
Role of OBD Locks and Aftermarket Solutions
They should fit an OBD port lock to prevent thieves from plugging in devices that reprogram keys or start the car. Simple mechanical OBD covers bolt over the port; choose one that resists tampering and uses secure fasteners.
They should combine OBD locks with phone-based immobilisers or aftermarket ECU locks that require a physical token or PIN to start. These layered defenses make remote relay attacks ineffective because even if the doors unlock, the engine won’t start without the additional authentication.
They should consult installers experienced with the vehicle make to ensure compatibility and avoid warranty issues. Verified installers can recommend specific OBD locks and hardwired immobilisers that work with the car’s CAN bus without creating new security gaps.
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