Relay theft explained — how modern cars are stolen without the key

The key is not stolen — its signal is relayed

On some keyless vehicles, the car checks for a recognised key nearby before allowing access or starting. In a relay attack, communication with a real key is relayed so the car behaves as though that key is close enough, even when it is still inside the owner's home.

This is not the same as making a permanent copy of a key. It also does not mean every modern car is vulnerable in the same way. Vehicle and key designs differ, so use your handbook or manufacturer guidance for advice about your exact system.

Start with the way you store your keys

• Keep keys away from doors and windows, and out of sight. Include the spare, not just the key you carry every day.
• Consider a suitable signal-blocking pouch or container. Check that the car no longer recognises the key while it is inside, following the product's instructions, and recheck periodically.
• Check whether your vehicle manufacturer provides a way to switch off passive keyless entry, and what effect that has on daily use.
• Do not assume that putting a key in any metal tin or wrapping it casually will reliably block communication.

A pouch and an immobiliser address different parts of the risk

A signal-blocking pouch is intended to prevent communication with the stored key. It only helps when the key is inside and the pouch is working. It is not an additional check on who is sitting in the driver's seat.

A personal-sequence immobiliser adds that separate driver-authorisation step. CAN Phantom states that it protects against relay theft: even if the vehicle accepts a relayed key signal, the personal sequence is still required before it can be driven normally. Compatibility must be confirmed for the vehicle.

Do not reduce all vehicle security to relay theft

Actual key theft, unauthorised key copying, theft of belongings and physical removal of a vehicle are different problems. Key storage alone is not a complete answer to all of them. A visible steering-wheel lock, sensible parking and an additional immobiliser can serve different purposes within a layered approach.

A tracker can support locating a stolen vehicle but should not be confused with the authorisation check that prevents normal driving. Check the actual functions of any product you are considering rather than relying on its name.

If something happens, avoid guessing the method

Footage of somebody opening a door or entering a vehicle does not, on its own, prove relay theft. Preserve any CCTV, note what you observed and contact the police and your insurer as appropriate. Do not confront people or attempt your own recovery.

The genuine CCTV on AccuKey®'s CAN Phantom page shows people accessing a vehicle which remains in place during the footage. We do not claim the footage identifies a particular theft technique, or proves that every future attempt would have the same outcome.