On Vehicle Diagnostic Capabilities

Aboard this vehicle are electronic components which can be controlled by the service technician to provide valuable self-diagnostic information. These components are part of an electrical network designed to control various engine and body subsystems.

System sensors and switches are monitored by the computer system. These components are
^ Body Function Controller (BFC)
^ Electronic Brake Control Module (EBCM)
^ Instrument Cluster
^ Powertrain Control Module (PCM)
^ Sensing and Diagnostic Module (SDM) - Supplemental Inflatable Restraint System (CKT 800 UART)

A combination of inputs from these components, other sensors and switches go to the computers either as discrete/analog inputs, communicated on the communications link (called the Data Line (circuit 1807 Class 2, or circuit 800 UART) and Serial Peripheral Interface (SPI) [circuit 1321, circuit 1322 and circuit 1323]) to other computers.