What is an immobilizer and how does it work?

The immobilizer is an electronic anti-theft device. As the name implies, its task is to immobilize the vehicle in the event of an unauthorized start of the engine. At the same time, disabled vehicle components remain blocked even if the immobilizer is disabled or mechanically damaged.

Anti-robbery models make it possible to start the engine and drive off for several hundred meters. When the car is at a certain distance from the owner who has a special key fob or card, the engine stalls. Often this happens in a crowded place, and the hijackers have no choice but to abandon the car. This option is useful, for example, if the driver was tricked into leaving the passenger compartment or forcibly thrown out of the car with the engine already running.

How does the immobilizer work and what does it disable?

Modern immobilizers are integrated into the electronic filling of the vehicle and block at least two main functions for starting the engine - the fuel system and ignition. Its work is based on the transmission / reading of a unique code, similar to how transponders do it on toll roads. In the most general form, the main elements of any immobilizer are:

• ignition key (transmitter), the key fob of which has a built-in chip with a pre-installed unique code;
• electronic control unit (ECU). Reads signals from the key and sends commands to vehicle systems;
• an actuating device, which includes one or more electronic relays. The switch connects or breaks the power supply circuits and thus blocks certain components of the car or allows them to work.

The immobilizer works like this: when the driver tries to start the engine, the encrypted code from the key is transmitted to the computer, and it reads it. If it is correct, then the engine starting systems will be unlocked and the car will be able to start moving. More advanced "keys" use rolling security codes. In fact, this is a two-level identification, in which there is a permanent cipher and a second, changing one. Each time the engine is started, the computer generates a second code and stores it in memory. Thus, the immobilizer first reads the personal code and then asks for a rolling code.

Some types of immobilizers require manual entry of a PIN code, others can be controlled using smartphone applications via Bluetooth. There are also systems that independently block the start of the engine after a predetermined time.

To find out if the car has a factory immobilizer, just look at the owner's manual. It will contain information about the type of system and how to use it. When buying a car “from hand”, the previous owner will probably tell you about the immobilizer when selling. But there are also "folk" ways. To do this, the key is tightly wrapped with food foil and inserted into the ignition. If the car does not start, then the immobilizer is installed. Also, the availability of the system can be checked by calling the dealer.

Types of immobilizers

There are several types of immobilizers that differ:

• activation method - contact (with a contact key, code and fingerprint) and contactless;
• type of installation - standard from the factory and additional;
• signal transmission - static or dynamic. In the first case, one unchanged code is transmitted, in the second - a changing one.

With contact key. It is activated through physical contact - that is, at the moment when the key is inserted into the ignition switch. These are the first and simplest models. Their work is based on the simple principle of closing / opening contacts, followed by processing and transmission of an electrical signal. The contact device can be in any form - from outdated tablets (like from an intercom) to more familiar ignition keys.

Code. Such immobilizers can be considered a kind of contact. To activate them, you need not only to connect a chip reader, but also to enter an additional PIN code on a special keyboard. In some systems, to unlock it is necessary to press, for example, the pedal a certain number of times, equal to the first digit of the code.

Fingerprint immobilizers. Such a system identifies the owner based on biometric data, namely a fingerprint. If the data matches, then the system will work. In case the driver was forced to read the imprint at risk, a "disturbing" imprint function is provided. Then the engine will be unlocked and will even work for some time, but will soon stall.

Contactless immobilizers. This is a whole group of modern systems that mainly differ in range. Depending on the last criterion, they can be divided into short-range immobilizers, long-range (with a radio channel) and long-range immobilizers with a motion sensor. The physical key can be in the form of a keychain, a credit card, or any other form. They work through a receiving antenna - a small sensor that is hidden in the interior trim. The range of such systems is from a few centimeters from the antenna to 1–5 m.

Which immobilizer is better?

If you want to equip your car with a more advanced anti-theft system or an existing immobilizer needs to be replaced, then there are two options - choose it yourself or contact specialists. Installation, however, is better to trust specialists in any case - it's more reliable. If you decide to choose an immobilizer yourself, then here are some tips:

• Examine the characteristics: number of security zones, type of control, method of blocking the engine, type of signal, additional functions (usually security and service), the presence of additional radio modules;
• Do not give preference to budget protection systems from little-known manufacturers;
• Pay attention to the warranty period, in the case of high-quality systems it is 3 years;
• The presence of anti-robbery algorithms (prevents theft when stopped at a traffic light);
• Complete the immobilizer with a car alarm.

If it is possible to install a control unit under the hood of a car, then do not refuse this option, because this guarantees more reliable protection. During the installation of the system or in the course of this work, study the operating instructions, and also familiarize yourself with the wiring diagram. If you are very concerned about car theft protection, then carry a key fob with a transponder (if it is not a Keyless system) in a separate bundle or in an inside jacket pocket. If lost, the immobilizer will have to be recoded.

The list of manufacturers of immobilizers is quite wide. Even small firms enter the market from time to time. Many anti-theft systems are being developed by Asian manufacturers, but their products are almost never found on European markets. Most Popular Brands:

• Starline;
• Ghost;
• Pandect.

Relatively budget models of protective systems can be found under the names of the brands Pandora, Tiger, Tomahawk, Raptor. However, keep in mind that many of the budget models are designed to reinsure rather than provide serious protection against theft.

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