Serial Communications Interface
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.
Serial Communications Interface (SCI) circuit is used by PCM to send data to and receive data and sensor activation signals from scan tool. Scan tool uses signals sent on SCI to display fault messages or diagnostic trouble codes, sensor voltages and device states (On/Off). Scan tool uses SCI to send solenoid and switch activation commands to PCM so that devices and circuits can be tested.