An immobiliser or immobilizer is an electronic security device fitted to a

motor vehicle A motor vehicle, also known as motorized vehicle or automotive vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on Track (rail transport), rails (such as trains or trams) and is used for the transportation of pe ...

that prevents the engine from being started unless the correct key (''transponder'' or '' smart key'') is present. This prevents the vehicle from being " hot wired" after entry has been achieved and thus reduces

motor vehicle theft Motor vehicle theft (also known as a car theft and, in the United States, grand theft auto) is the criminal act of stealing or attempting to steal a motor vehicle. Nationwide in the United States in 2020, there were 810,400 vehicles reporte ...

. Research shows that the uniform application of immobilisers reduced the rate of car theft by 40%.

Description

The electric immobiliser/alarm system was invented by St. George Evans and Edward Birkenbuel and patented in 1919. They developed a 3x3 grid of double-contact switches on a panel mounted inside the car so when the ignition switch was activated, current from the battery (or magneto) went to the spark plugs allowing the engine to start, or immobilizing the vehicle and sounding the

horn Horn most often refers to: *Horn (acoustic), a conical or bell shaped aperture used to guide sound ** Horn (instrument), collective name for tube-shaped wind musical instruments *Horn (anatomy), a pointed, bony projection on the head of various ...

. The system settings could be changed each time the car was driven. Modern immobiliser systems are automatic, meaning the owner does not have to remember to activate it. Immobilisers have been mandatory in all new cars sold in Germany since 1 January 1998, in the United Kingdom since 1 October 1998, in Finland since 1998, in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

since 2001 and in Canada since 2007. Early models used a static code in the ignition key (or key fob) which was recognised by an

RFID Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromag ...

loop around the lock barrel and checked against the vehicle's

engine control unit An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by re ...

(ECU) for a match. If the code is unrecognised, the ECU will not allow fuel to flow and ignition to take place. Later models use rolling codes or advanced cryptography to defeat copying of the code from the key or ECU. The microcircuit inside the key is activated by a small electromagnetic field which induces current to flow inside the key body, which in turn broadcasts a unique binary code which is read by the automobile's ECU. When the ECU determines that the coded key is both current and valid, the ECU activates the fuel-injection sequence. In some vehicles, attempts to use an unauthorised or "non-sequenced" key cause the vehicle to activate a timed no-start condition and in some highly advanced systems, even use satellite or mobile phone communication to alert a security firm that an unauthorised attempt was made to code a key. Coincidentally, this information is often recorded in modern automobile ECUs, which may record many other variables including speed, temperature, driver weight, geographic location, throttle position and yaw angle. This information can be used during insurance investigations, warranty claims or technical troubleshooting.

Availability

Add-on immobilisers are available for older cars or vehicles that do not come equipped with factory immobilisers. The insurance approval for a self-arming immobiliser is known as "Thatcham 2" after the Motor Insurance Repair Research Centre in Thatcham, England. Approved immobilisers must intercept at least two circuits; typically the low-voltage ignition circuit and the fuel pump circuit. Some may also intercept the low-current starter motor circuit from the key switch to the relay. Statistics in Australia show that three out of four vehicle thefts are older cars stolen for

joyriding Joyriding refers to driving or riding in a stolen vehicle, most commonly a car, with no particular goal other than the pleasure or thrill of doing so or to impress other people. The term "Joy Riding" was coined by a New York judge in 1908. Joy ...

, transport, or to commit another crime. Immobilisers are fitted to around 45% of all cars in Australia, but account for only 7% of those cars that are stolen. In many instances where a vehicle fitted with an immobiliser has been stolen, the thief had access to the original key. Only around one in four stolen vehicles are stolen by professional thieves. The majority of vehicles are stolen by opportunistic thieves relying on finding older vehicles that have ineffective security or none at all. Honda was the first motorcycle manufacturer to include immobilisers on its products in the 1990s. In September 2007, a Transport Canada regulation mandated the installation of engine immobilisers in all new lightweight vehicles and trucks manufactured in Canada. Lack of immobilizers in many Kia and

Hyundai Hyundai is a South Korean industrial conglomerate ("chaebol"), which was restructured into the following groups: * Hyundai Group, parts of the former conglomerate which have not been divested ** Hyundai Mobis, Korean car parts company ** Hyundai ...

U.S. models before mid-2021 made these cars targets for theft in 2020 and 2021, especially in Milwaukee County, Wisconsin and

Columbus, Ohio Columbus () is the state capital and the most populous city in the U.S. state of Ohio. With a 2020 census population of 905,748, it is the 14th-most populous city in the U.S., the second-most populous city in the Midwest, after Chicago, and t ...

Cracking

Numerous vulnerabilities have been found in the immobilisers designed to protect modern cars from theft. Many vehicle immobilisers use the Megamos-chip, which has been proven to be crackable. The Megamos transponder is one of many different transponders found in today's immobiliser systems and also comes in many different versions. Hacking of an immobiliser in the real world would be performed on the vehicle, not on the key. It would be faster to program a new key to the vehicle than to try to clone the existing key, especially on modern vehicles. Some immobiliser systems tend to remember the last key code for so long that they may even accept a non-transponder key even after the original key has been removed from the ignition for a few minutes.

Effectiveness

A 2016 study in the '' Economic Journal'' finds that the immobiliser lowered the overall rate of car theft by about 40% between 1995 and 2008. The benefits in terms of prevented thefts are at least three times higher than the costs of installing the device.

References

External links