Operation - Ignition Sense - Pcm Input
WARNING: This page is about a different car, the 2005 Dodge Grand Caravan, 2005 Dodge Caravan, and 2005 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.