Overview of Keyless Ignition Systems
Overview:
Keyless ignition systems work by replacing the ignition switch in a vehicle with an electronic device commonly referred to as a radio frequency identification (RFID) module. There is one component of the RFID system inside the ignition circuit of the car, and another in a key fob carried by the owner. The two RFID devices have to communicate with each other before the car can start. In standard start systems, the ignition key trips a relay, which in turn supplies power to the starter motor. In a remote start vehicle, the relay is tripped only when two conditions prevail. These are:
1) The remote RFID key fob carried by owner comes within 20 feet of the car, and
2) The driver presses the push-button start.
The (vastly oversimplified) diagram shows the three possible conditions.
A. The key fob is more than 20 feet away from the RFID device inside the car. The ignition relay is open, and the push-button start is open.
B. The key fob communicates with the RFID device in the car when it is less than 20 feet away, but the push-button is not depressed.
C. The key fob is within range, AND the driver presses the start button.
The RFID modules communicate by way of encrypted signals, in order to provide security.
Simplified view of remote start system
