Car immobilisers are electronic security devices that can prevent car theft by making it impossible to hot-wire a vehicle. It prevents the engine from starting or the car’s features from functioning unless the correct key or key fob is present. But how does it work? And do you have one or need one? This article answers these questions and should leave you confident in understanding this essential aspect of car security.
Types of immobiliser
Electronic immobilisers
- Electric immobilisers connect your key or key card to the car. If a thief uses a makeshift key that doesn’t have the immobiliser, the car won’t start.
Mechanical immobilisers
- Mechanical immobilisers may allow the engine to start, instead relying on other locking aspects that mean the car cannot be controlled. For example, the steering wheel will not be able to turn, or the gear stick might be locked.
How does a car immobiliser work?
Here’s a breakdown of how it functions:
- Your car key or key fob contains a transponder chip, a small microchip with its own unique electronic code.
- The car’s computer, or Electronic Control Unit (ECU), controls the immobiliser system and stores the vehicle’s correct code.
- When you use your key (whether inserting it into the ignition or using the key fob in a keyless entry car), the immobiliser system sends a signal to the transponder chip. The chip then transmits its unique code back to the ECU.
- The ECU compares the code it receives from the key with its stored code. If the codes match, the ECU allows critical engine systems to operate, enabling the car to start. If the codes don’t match, the ECU disables one or more engine operations (ignition, exhaust system, etc), preventing the engine from starting.
This technology has impacted car theft enough that vehicles with an approved immobiliser can receive lower insurance premiums.
Do all cars have immobilisers?
You may be thinking, ‘Does my car have an immobiliser?’ as some cars can be fitted with them. Indeed, while many modern vehicles are equipped with standard immobilisers, older models might not be. In the UK, around 45% of people drive cars that are a decade or older. However, all new vehicles sold after 1998 are legally required to have an approved immobiliser fitted. To check if your car has one, you can refer to your vehicle’s manual or look for an immobiliser symbol on your dashboard (often a key with a line through it or a car with a lock).
Can I upgrade my car immobiliser?
Yes, you can upgrade your car immobiliser, but you need to know what is compatible with your car. There are many different types and brands of immobilisers and the main difference is their age.
Traditional car immobiliser
- Traditional immobilisers require a physical key or card for them to function correctly.
A ghost immobiliser / or a more modern immobiliser
- A modern or ghost immobiliser is more discreet and connects to your vehicle’s CAN-BUS system. It requires a unique, user-defined sequence of existing buttons within the car (e.g., on the steering wheel, door panels or dashboard) to be pressed before the engine starts. This means there are no extra key fobs or LED indicators to give away its presence.
Advice to take away
In summary, car immobilisers are crucial anti-theft devices. If you want more information or wish to upgrade your current immobiliser, consult a trusted retailer or local garage for expert advice on types, features, suitability and proper installation. Correct installation is essential for effectiveness, as poor installation renders immobilisers dysfunctional and leaves your vehicle vulnerable. Prioritise your vehicle’s security and look into the best car immobiliser for your car today.
