Ignition Sense
WARNING: This page is about a different car, the 2003 Dodge Intrepid, 2003 Chrysler Intrepid, 2003 Chrysler Concorde, and 2003 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
The ignition sense input informs the Powertrain Control Module (PCM) that the ignition switch is in the crank or run position.