How Do Car Keys Work?

by Chad Hunter


Car ignition systems have been around for almost as long as cars themselves. Automobiles run on a combination of electric and fuel-based systems that work together to run and move the vehicle. Keys are basically shapes of cut metal which are manufactured with ridges and grooves that fit into expecting receivers of a lock.


The car key serves several purposes. It gains access to the car and it starts it. A car's ignition system is a combination of a low voltage trigger, multiple sensors, an ignition coil an engine control module. The system remains dormant until the car key is fully utilized. When the key enters the car key ignition and turns fully, it unlocks the system which sends voltage to the secondary ignition system. It is this system that begins to fire up the coil wire, cap and rotor and the additional systems of a car.

How Car Keys Work

Car keys allow for partial access to different portions of the vehicle. Turning the car to the "ACC" marking will allow for voltage to the electrical systems of the car (e.g. windows, radio and wipers.) When the key is set to "OFF," the vehicle and its ignition and electrical systems are shut down. Turning the key to the "ON" position will allow for temporary voltage to run the lights but will result in error messages from the car (e.g. battery light will illuminate, oil pressure may appear.) This is the preparation stage for the ignition system. The final car key setting is fully starting the engine and vehicle. It activates all systems and locks the car key to prevent removal while the car is running.


Modern car keys now come with additional features as opposed to car keys in the late 1990s and early 2000s. Car keys now come with microchips built within to complete validation by the ignition system of the vehicle. Car keys also come as valet keys which will only allow valet drivers to start the car but not open the glove compartment or trunk. Car security of modern vehicles also incorporates steering column locking or gear lever locking. Steering locks will prevent the movement of the wheel and activation of the ignition system unless the proper car key is used. Gear lever locking will prevent the vehicle from shifting out of park unless the proper car key is used. These security systems are dependent on both the proper cut of the grooves in the key and the microchip being in place also. While car keys could be copied, the micro-circuitry portion is only available via the car manufacturer.

About the Author

Chad Hunter is a freelance writer and author. Hunter began writing professionally in 1993 and has written for, Baton Rouge Parenting and additional newsletters, magazines and online publications. He holds a Bachelor of Science in computer networking from Purdue. Hunter is also a guest lecturer.

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