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 key fob can be inserted if the key fobs battery is dead, weak, or the radio frequency signal is being interrupted.
The immobilizer control module will send a low frequency radio frequency challenge to the key when the start button is pressed. The immobilizer coil is controlled by the BCM. The immobilizer control module is also active when learning vehicle keys.