Jeep Liberty/Electrical/PCI Bus

The "PCI" bus is the central communications bus in the Jeep Liberty. The BCM, PCM, TCM, WCM, EVIC, dash cluster, and audio equipment use it to communicate with each other. The bus is a superset of OBD-II and uses the J1850 VPW communication format. It travels throughout the entire car and the OBD-II port taps directly into it. The ELM327 chip from Elm Electronics should allow reading and writing to the bus via a serial port. One of the many available OBD-II interface tools could also be used. The Liberty won't switch to the newer and faster CAN bus until it is federally required in 2008.