Keep Alive Power (KAPWR)
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
KAPWR provide a constant voltage input independent of ignition switch state to the PCM. This voltage is used by the PCM to maintain the keep alive memory (KAM).