DESCRIPTION & OPERATION
| WARNING | Vehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in AIR BAG RESTRAINT SYSTEM article. |
| CAUTION | When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery. |
There are three data lines in the system. The 800 circuit data line is the Universal Asynchronous Receiver/Transmitter (UART) data line. It allows the Powertrain Control Module (PCM), Sensing and Diagnostic Module (SDM), HVAC Programmer, instrument cluster and Electronic Brake/Traction Control Module (EBTCM) to communicate by transmitting data.
The 1807 data line is the Class 2 data line that the PCM and Remote Function Actuator (RFA) Module communicates on. The 835 circuit is the entertainment and comfort data line, allowing communication between the HVAC programmer, Driver Information Center (DIC)/HVAC control assembly, CD changer and radio. A scan tool can be connected to the Data Link Connector (DLC), allowing the scan tool to communicate with the data lines. System operations can then be monitored for diagnostic purposes.
See also:
• COMPUTER RELEARN PROCEDURES