Immobilizer Coil Assembly
WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
The keyless entry immobilizer coil assembly is located in the center console. It has a small pocket above where the transmitter can be inserted if the transmitter battery is dead, weak, or the radio frequency signal is being interrupted.
The purpose of the immobilizer coil is to send a low frequency radio frequency challenge to a learned key when the start button is pressed. The immobilizer coil is controlled by the Body Control Module.
The other function of the immobilizer coil is for learning the keys to the vehicle.