A push button start key fob is a button that allows drivers to start their engine by pressing it. That said, you won't be able to turn on your car if you don't apply your vehicle's brakes.

The keyless car is a marvel of engineering. But how is it that they can start even when the battery in your key fob goes dead? The answer lies in science.

A key fob with remote locking/unlocking and push-button start. A key fob with push-button start and keyless entry that owners can leave in their purse or pocket for virtually all functions.

Learn how to choose and install a new Ford Fusion key fob battery to keep yours in perfect working order.

Push-button ignitions work via the fob, also known as a "smart key," which allows a driver to keep the device in a pocket, purse or other place when unlocking, locking and starting the vehicle.