A remote car starter allows a vehicle to start without a key or the presence of a driver. Remote car starters are useful for warming a car in cold weather, getting the air conditioning system going in hot weather, heating the car's oxygen sensor, and priming the emission controls.
A remote car starter transmits a signal at the push of a button to a module installed in the vehicle. A connection exists between this module and the ignition system. When the module receives the signal from the transmitter, which is usually on a key ring, it tells the ignition to turn on the car just like a key would. The signal is unique to the car, helping prevent theft, according to Waxwerks.