What is Engine Immobilizer? – The Ultimate Guide in 2022

An engine immobilizer is an anti-theft system built into the engine control unit invented by St. George Evans and Edward Birkenbeul in the early 1900s. The conventional engine immobilizers had to be activated every time the car would be driven. But, as technology progressed, new digital systems upgraded the conventional systems, and the automobile owners did not necessarily have to activate the engine immobilizer every time.

What is Engine Immobilizer?

An immobilizer translates to obstructing motion; thus, an engine immobilizer is an effective anti-theft security system that has become indispensable in today’s era, especially due to the increasing crimes of stealing cars, trucks, and motorbikes while they are parked, and the owner is away from the vehicle.

An electronic security device, the engine immobilizer impedes/ prevents the activation of the ignition circuit and the fuel system of the engine if the car key used is NOT the authorized vehicle key.

In simple words, if the key used to start the vehicle is not the authorized key that was provided officially, then the Engine Immobilizer would not allow the vehicle to start, leading to prevention or delay in theft.

How does an Engine Immobilizer Work?

The automobile key that is officially delivered or provided by dealers is equipped with a security system. Today, every vehicle comes with a smart key that consists of transponder chips. These chips work as messengers, transmitting signals of a digitally coded unique number to the engine management system. The match of the same ignites the engine allowing mobilization of the automobile.

If the key put into the ignition is not the authorized one then the vehicle’s engine immobilizer gets activated preventing the start of the engine.

The Advanced Engine Immobilizer System (Electronic)

A two-tier security system, the Advanced Engine Immobilizer System contains two codes. The first code is permanent. The second code would change every time the key ignites the engine, and the vehicle becomes mobile.

The second code is reversely communicated to the smart key and is stored until it is changed again by the system.

When the driver starts the vehicle the engine immobilizer primarily reads the first code followed by the second. If the second code mismatches or ignition of the engine circuit is tried through short circuiting, the immobilizer system would be instantly activated.

What Does an Engine Immobilizer Do?

Researches indicate that engine immobilizers have reduced car theft by 40% as the smart anti-theft security system does not allow motor vehicles to run until the authorized key is presented to start the vehicle.

Can Engine Immobilizer Work if the Smart Key is Duplicated?

Easy duplication of smart key is a next to impossible task.

As the signal carrying the code is transmitted by the transponder chips in the smart key, duplication of the same is not easy. However, if the owner loses the key or decides to get a new one, then deactivation of the old smart key can only be done officially by the authorized dealers. A new smart key request is sent to the manufacturer after scrutiny of all credentials.

Do Engine Immobilizers Malfunction? 

Engine Immobilizers can malfunction. Look out for these signs-

  1. Issues with locking and unlocking the vehicle with your smart key
  2. Trouble while starting the automobile
  3. Flashing of the warning light on the dashboard
  4. Frequent alarm blaring

What to Do When Engine Immobilizers Malfunction?  

The transponder chips in the key fob or smart key rely on a battery. Replacing the same may prevent the malfunctioning of the anti-theft security system.

However, if the problem persists then consulting with the authorized dealer would be recommended.


As technology improves, newer systems to tackle motor theft have been invented or upgraded by motor companies. Today, engine immobilizer, engine management systems, smart keys, and transponders chips have become an inevitable part of automobile anti-theft systems enabling the safety of vehicles across the world.

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