Keyless Entry And Start

Antennas in the car detect the key nearby. Start is by button; the immobilizer checks the key first. Some systems use a phone as the key. Sensors in the door handles detect your hand to unlock, and touching a marked area or pressing a button on the handle locks the car.

The car sends a low-frequency signal and the key answers with an encrypted code.

Relay attacks can extend the key signal; signal-blocking pouches or motion-sensing keys help. A weak key battery can cause "key not detected" messages.