Circuit/System Description
WARNING: This page is about a different car, the 2008 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
The rear compartment keyless entry antenna is used as a short range low frequency (LF) transmitter. As a vehicle with a closed rear compartment lid is approached with a key fob and the rear compartment lid release switch is pressed, the keyless entry antenna transmitter broadcasts a challenge to the key fob in an approximate 1 meter range. If the response from the key fob via radio frequency (RF) is valid, the latched rear compartment will be passively unlocked/unlatched, allowing the rear compartment area to be opened.