Power Mode Description and Operation: Notes
WARNING: This page is about a different car, the 2005 Pontiac G6. However, it is still accessible from the selected car via links, so may be relevant.
Power to many of this vehicle's circuits are controlled by the module that is designated the power mode master (PMM). This vehicle's PMM is the body control module (BCM). The PMM controls which power mode (Run, Accessory, Crank, Retained Accessory Power, or Off) is active.