immobilizer emulator

Immobilizer - what is it?

An immobilizer (translated from English immobilizer - “immobilizer”) is an electronic anti-theft device, the main function of which is to block some vehicle modules in case of unauthorized access (hijacking). As a rule, the immobilizer blocks the operation of the fuel system or ignition, as a result of which the car engine either does not start or stops working after a certain time.
This device is included in the factory equipment of all modern cars and is listed in the documentation as a “regular immobilizer”. Also, in addition to the regular factory immobilizer, additional non-standard immobilizer emulator with other functionality and principle of operation can be installed in the car.

In fact, immobilizers are a more modern version of the "secret buttons" that were widely used by motorists back in Soviet times. With the help of such "secrets" (which were installed in secret places in the cabin), the power supply from the battery was turned off. As a result, the de-energized starter did not "start" and did not start the engine.

Immobilizer configuration

The immobilizer anti-theft device consists of the following elements:

• Electronic unit – performs processing of data received by a signal from a transponder (chip or from a separate tag) or when dialing a digital code manually.
• Blocking relay - for opening/closing the electrical circuit.
• Antenna (for non-contact immobilizers) – receives a radio signal from a transponder (chip or tag). In this case, several different antennas can be used for the device. The most common is the ring antenna, located around the ignition switch.
• Transponder (for non-contact immobilizers) – a radio chip or radio tag (essentially the same thing) with a certain range at a distance, for transmitting a radio signal with a code through the antenna to the electronic control unit of the immobilizer.
• Contact key (for contact immobilizers) - applied to a specific place. Some contact immobilizers use a fingerprint scanner. Accordingly, in this embodiment, a finger is applied instead of a contact key.
• Panel with digital buttons (for coded immobilizers) – for manual code entry.

Types of immobilizers

All immobilizers can be divided into three main types, differing from each other in design features and functionality:

1. Contact.
2. Contactless (remote).
3. Code.

Contact immobilizers.

Based on the name “contact”, a contact is required to control such immobilizers. As a similar example, we can cite well-known intercoms with chip keys, where to open the door you need to attach a chip to a certain place on the intercom body. The same principle of operation for contact immobilizers with a chip key. To unlock the engine, you need to attach a chip key to a certain place. In a more modern version, a scanner is used to identify the owner by fingerprint.

Contactless (remote) immobilizers.

The most modern type of immobilizers that work remotely (contactless), with a certain range. In this case, the signal reception radius can be from several centimeters to several meters. To start and operate the engine, a radio signal is required from a chip (transponder) in the ignition key or from a separate radio tag.

Radio-tagged immobilizers help prevent car theft even if the attacker has a "native" ignition key. For example, it is not uncommon for a driver to be forcibly removed from a car while the engine is running, or the car key is simply taken from him. There are also cases of theft when the driver independently leaves the car with the engine running or with the key left in the ignition. If the immobilizer works from a radio tag located in the driver's pocket, then the engine will stall after a while when theft occurs. In this case, when driving a car without a driver with a radio tag, the range of the signal from the tag will be exceeded, and the immobilizer will stop receiving the signal. As a result, blocking will work, and the engine will stop working. With this principle of operation of the immobilizer, the code is read from the radio tag constantly, at short intervals.

In simpler versions of devices, without a radio tag, the code signal from the transponder (radio chip) in the ignition key is read once with each new engine start. That is, while the engine is running, the code is not re-confirmed (reading).

In some types of contactless immobilizers, radio tag functions can be performed by a smartphone with a special program that works via Bluetooth (wireless data exchange over a short distance).

Coded (button) immobilizers.

The code-button type of immobilizers has been used for a long time and is the simplest option. In such devices, the code is entered manually, by simply dialing the desired combination of numbers (PIN code) on a keypad, which is usually installed in the car. However, the option with simple number buttons is considered obsolete. There are more modern models of push-button immobilizers, where instead of the usual buttons with numbers, regular buttons on the steering wheel or dashboard are used, designed for completely different purposes. For example, the buttons for the horn and power window on the steering wheel can be used to release the lock. They will need to be pressed in a certain sequence and a certain number of times.

Basic working principle

After turning on the ignition, the immobilizer requests an identification code confirming authorized access. Depending on the type of immobilizer, this code can be obtained by contact, contactless or push-button method. Further, the received code is processed in the electronic unit, and if it is correct, then the corresponding modules are unlocked to start the engine.

After turning off the engine and removing the key from the ignition, the immobilizer performs a protective lock. Depending on the type of immobilizer, engine blocking can be carried out both at the software level (via the CAN bus and the electronic engine control unit), and by opening the most important electrical circuits (starter, ignition) using an electromagnetic relay. It is also possible to stop the fuel supply to the engine using a solenoid valve.

Some immobilizers have a hood lock function to protect the wiring and devices in the engine compartment of the car. Since some types of immobilizers are not installed in the car, but in the engine compartment, which is a more reliable option.

4 misconceptions about immobilizers

1. A key with a chip (transponder) cannot work without a battery.
In fact, the code chip (transponder) built into the ignition key can also work without a battery. The battery in the key housing is only needed for the operation of the buttons that control the central lock. The exception is the radio tag, which actually runs on batteries.

2. The immobilizer is harmful for domestic cars and it is better to turn it off, because it often “bugs” and prevents the engine from starting.
Such a statement can often be heard from low-skilled professionals. As practice has shown, it all depends on the correct installation of the device. Correctly and correctly installed immobilizer does not interfere with engine operation.

3. Any key with a transponder can be copied. That is, you can make a duplicate of it as from a regular key.
This option was possible earlier, when immobilizers had a lower degree of protection. Today, in the vast majority of cases, making a duplicate key with a transponder is impossible. If you lose the "native" key, you will have to purchase a new one and register it in the immobilizer control unit.

4. The transponder key may become demagnetized.
The transponder key does not work according to the magnetic principle, and therefore cannot be demagnetized.

Finally

At the moment, there are a large number of different models of immobilizers from different manufacturers. Russian-made domestic devices have proven themselves well. The protective properties and functionality of immobilizers are constantly being improved and expanded, as the methods of stealing vehicles are constantly being improved. Therefore, many devices quickly fall into the category of obsolete.