For the vast majority of people, cranking your car involves getting the key out, sliding it into the ignition, and turning it to the “run” position. However, if you have a push-button start system, then you don’t have to do that. You just get inside and push the button labeled start/stop, and the engine roars to life. Simple and easy, right? Actually, these are pretty complicated systems.

The purpose of a push-button start system

You might think that the primary purpose of a push-button start system is convenience, but you’d only be partially correct. They’re really designed to discourage theft. Because there is no physical key necessary to crank the car, it actually makes it harder for would-be thieves to make off with your vehicle.

Though you don't need a traditional key to get the car started, you need a special fob. It can stay in your pocket, where it broadcasts a signal to the car’s computer. The computer recognizes the fob’s code, and lets you crank the ignition. Of course, there are some safeguards in place. For instance, you can’t start the engine if you’re not holding the brake and have the car in park. If either of these conditions isn’t met, the engine won’t start.

Another safeguard here is that the car’s computer is only able to recognize the code from your specific key fob. This means that another driver with their car's fob won’t be able to get in and start your engine.

How a push-button start works

The only real difference between a push-button start system and a conventional keyed ignition is that you don’t need a key to close the circuit on the ignition. The button does that. Pushing the button does the same thing that turning the key does. The fob is really the beauty behind the system, which ensures that only you can start the car.

Potential problems

There are a few issues with push-button start systems, though. For instance, the fob can be removed from inside the car during operation and it will not affect operation. The engine will keep right on running until the car runs out of gas. Another potential issue is the fact that the car can be shut off while still in drive, which means that it may roll accidentally if you were to get out of the car without applying the parking brake.

This article originally appeared on YourMechanic.com as How Does a Push-Button Start Work? and was authored by Valerie Johnston.


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