Programmable Communication Interface Bus Circuit

The Programmable Communication Interface (PCI) bus circuit is a multiplexed network capable of supporting binary encoded messages shared between multiple modules and the Data Link Connector (DLC). The PCI bus circuit is connected by a single Violet/Yellow wire. Each PCI bus circuit component uses its local grounds as bus reference. If more than one module is trying to access the PCI bus circuit at one time, the code being sent determines which message has higher priority, and is then allowed to access bus circuit first. Communication over the bus circuit is essential to proper operation of vehicles on-board diagnostic systems and Diagnostic Readout Box (DRBIII) scan tool or generic scan tool. Problems with operation of bus circuit or scan tool must be corrected before proceeding with diagnostic testing.