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 in RESTRAINTS. |
| 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 two data lines that can be accessed with a scan tool. The 800 circuit data line is the Class 1 data line. It allows the Sensing and Diagnostic Module (SDM), HVAC programmer and Electronic Brake Control Module (EBCM) to communicate by transmitting data. The 1807 data line is the Class 2 data line that the PCM and Remote Function Actuator (RFA) communicate on. A scan tool can be connected to the 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