Modern cars come with factory-installed theft protection, though it's not the most robust. You can't start the car without the original key. Typically, the standard immobilizer is used for blocking the ignition. We'll explain how the immobilizer works in a car, how reliable it is, and whether bypassing the immobilizer is possible.
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How does a car immobilizer work?
Many have heard the term 'immobilizer,' but not everyone
knows what it is in a car.
Most modern cars come with an electronic key, even if you
need to start the engine using a traditional key with a metal blade. The
electronic key not only allows you to lock and unlock the doors, but it also
contains a tag—a chip with a specific code. When you insert the key into the
ignition, the control unit reads and verifies it. If the code is correct, the
lock is released. If the code is incorrect, the engine will not start.
Advanced systems use a more complex algorithm. The control
unit reads the code, generates its own, and sends an encrypted message to the
chip in the key. The chip processes it and provides a response code. The ECU
knows the 'correct answer,' and the engine will only unlock if the code
matches.
In models where the engine is started using a button, the
principle of how the immobilizer works remains the same. The key is still
queried, and the codes are compared.
What does an immobilizer consist of?
Such devices can be divided into three components.
1.
Key or card with a chip.
2.
Control unit that reads the
code.
3. Electromagnetic relay that
interrupts the engine's control circuits.
The relay is responsible for directly blocking the vehicle.
What does the immobilizer block? It can be the circuits for the starter, fuel
pump, or ignition coil. Relays can also activate only at the start of movement,
meaning you might be able to start the engine without the original key, but you
won't be able to drive away.
What types of immobilizers are there?
Immobilizers are such popular devices that they are installed
both at the factory and in regular service centers as an additional protection
against theft. Factory versions are well-studied by thieves, so they do not
pose a challenge for 'professionals' with the right equipment. Immobilizers can
be divided into two classes.
Contact immobilizers
So, what is an immobilizer in a car, specifically a contact one? Essentially, it's a switch. If it is open, the power supply to the circuit is blocked. These immobilizers were often connected to a hidden button, which was tucked away in a secret spot. Before starting the engine, you would need to press the button.
There are contact immobilizers with microprocessor control.
In these, you don't just press the button; you have to do it in a specific
way—for example, quickly press it twice, pause for a second, and then press
again. Interestingly, the button may be a factory-installed one that serves a
seemingly 'harmless' function, such as cruise control, at other times. Another
complex contact control option is entering a code.
What's the downside of these immobilizers? They are easy to
find because they are installed within the driver's reach. If the driver
repeatedly reaches into the glove compartment, under the seat, or another area,
it is not hard to trace their actions.
Contactless immobilizers
They are essentially a tag and a reader. The tag can be a
regular key fob or a plastic card (for convenience, so you can carry it with
your documents). As soon as the driver gets into the car, a hidden receiving
antenna reads the code, and if it is correct, the device allows the engine to
start. This is convenient because no action is required from the driver. It's
also impossible to determine the presence of an immobilizer by external signs.
How to know if there is an immobilizer in a car
Determining whether there is an electronic lock in a car may
sometimes be necessary not only for criminals but also, for example, after
buying a used car. An older model may not have even a factory-installed
immobilizer. To check this, you need to isolate the chip that should be in the
key.
For cars that start with a button, you can leave the key far
away (for example, at home) and try to start it, or even better, try to drive
without the key inside. If it doesn't work, then there is an immobilizer.
For cars with a traditional ignition lock, you can shield
the electronic components by wrapping the key in several layers of foil,
leaving only the metal blade exposed. If the car does not start and an
indicator flashes on the dashboard, usually in the form of a car with a key
inside, then there is an immobilizer in the car.
How to start a car without an immobilizer
Bypassing the immobilizer may be necessary not only for car thieves but also for car owners. For example, if something happens to the electronic key, such as it being submerged in water or broken. The most common scenario is the installation of a security system with remote start.
Do not attempt to find out how to reset the immobilizer right now. You can only turn it off if you have prepared for it in advance. How can you do this?
1.
Disable the immobilizer
programmatically: This is mainly possible in cars manufactured before 2010. The
downside is clear: the car remains unprotected.
2.
Hide a second or third key:
The important thing is to place this key near the ignition lock. Then you can
start the car with a screwdriver if necessary. This method is usually used when
installing more advanced security systems, but it still reduces the anti-theft
potential.
3.
Use a bypass device: These
are special devices that transmit the required code to the ECU. They may
contain chips extracted from original keys or a complex circuit capable of
reproducing the immobilizer code. They operate within a non-factory anti-theft
system, essentially duplicating the factory immobilizer. This method is the
most reliable in terms of protecting the car from theft.
So, in brief:
– An immobilizer is a device that blocks the engine from starting (or its operation when an attempt is made to begin driving).
– An immobilizer consists of a chip, a control unit, and a relay that directly block the circuits.
– In addition to factory-installed immobilizers, there are aftermarket ones, which are installed as an additional measure to prevent theft.
– Such devices can be contact-based (operating with a button) or contactless.
– Starting the engine without an immobilizer key (bypassing) is not straightforward.{alertSuccess}