Circuit/System Description
WARNING: This page is about a different car, the 2019 Cadillac XT5. However, it is still accessible from the selected car via links, so may be relevant.
The keyless entry antennas are used as short range low frequency transmitters. As a vehicle with locked doors is approached with a keyless entry transmitter and the exterior door handle/rear closure touch pad is pressed, the keyless entry antenna broadcasts a challenge to the transmitter in an approximate one meter range. If the keyless entry control module verifies the response from the transmitter via radio frequency (RF) is valid, the keyless entry control module will send a message to the remote control door lock receiver and the locked door will be passively unlocked/unlatched and allow the door to be opened.