Operation - Ignition Sense - Pcm Input
WARNING: This page is about a different car, the 2004 Dodge Grand Caravan, 2004 Dodge Caravan, and 2004 Chrysler Town & Country. 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.