Keep Alive Memory (KAM)
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.
The PCM stores information in KAM (a memory integrated circuit chip) about vehicle operating conditions and then uses this information to compensate for component variability. KAM remains powered when the ignition switch is off so that this information is not lost.