Car Theft Prevention: How Thieves Steal Cars & How to Stop Them

Understanding modern theft methods — and the security that actually works.

Relay attacks · CAN injection · Physical immobiliser · From £79

Vehicle theft in the UK has evolved. Gone are the days of hotwiring. Modern thieves use electronics: relay amplifiers, CAN injectors, and OBD programmers. Understanding these methods is the first step to protecting your car. LockCar’s physical relay immobilisers are designed specifically to defeat these electronic attacks.

Relay attacks: how they work

Relay attacks target keyless-entry vehicles. Thieves work in pairs. One stands near your front door with a relay amplifier, capturing your key fob’s signal from inside your house. The signal is transmitted to a second device held near your car. The car thinks the key is present and unlocks — and starts. The whole process takes under 60 seconds. Prevention: store keys in a faraday pouch (signal-blocking), and fit a physical immobiliser that doesn’t rely on key fob signals.

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Faraday pouches stop relay attacks when your key is stationary at home. But they don’t protect you when you’re out — a thief can still relay your key from a restaurant table. An immobiliser protects you everywhere.

CAN injection and OBD cloning

CAN injection is a newer, more sophisticated attack. Thieves access the vehicle’s CAN bus (the communication network) — often via headlight wiring or the OBD port — and inject a “start” command. The car’s ECU accepts this command as genuine and starts the engine. OBD cloning involves programming a blank key fob via the OBD port, creating a new authorised key. Both methods defeat factory immobilisers. LockCar’s relay-based immobilisers are not vulnerable to CAN injection because they do not accept start commands from the CAN bus.

60sTime to steal a car with relay attack

£50-200Cost of CAN injector devices online

£79From for LockCar i226 immobiliser

LockCar immobiliser range — effective prevention

Recommended

LockCar IC3ST — £139

Standalone app + tag immobiliser

Physical 20A relay cut. Requires app or tag to start. Not vulnerable to relay attacks, CAN injection, or OBD cloning.

LockCar IS357 — £149

Dual-factor immobiliser

App + tag required. Maximum security for high-value vehicles. No CAN bus vulnerability.

LockCar One Plus — £259

4G tracker + immobiliser

Prevention (immobiliser) plus recovery (GPS). Remote immobilisation from anywhere.

Can a thief bypass a physical relay immobiliser?

Bypassing a hidden, hardwired relay requires physical access to the relay location and mechanical bypass (installing a jumper). This takes significant time — most thieves will move to an easier target.

Is a steering wheel lock enough?

Steering wheel locks are visible deterrents, but they can be cut or drilled in minutes. They don’t prevent electronic theft methods. Use them alongside an immobiliser, not instead of one.

Immobiliser — UK wide