GM Service Manual Online
For 1990-2009 cars only

Data Link Connector (DLC)

The DLC provides a power source for the scan tool as follows:

    â€¢ Unswitched voltage (B+) at DLC terminal 16 (circuit 440)
    â€¢ Ground at terminal 4 (circuit 1550) and terminal 5 (circuit 1550)

Class 2 Serial Data Link

The class 2 serial data link allows the following modules to communicate data with each other:

    â€¢ Electronic brake control module/electronic brake traction control module (EBCM/EBTCM)
    â€¢ Instrument cluster (IPC)
    â€¢ Powertrain control module (PCM)
    â€¢ Pass key III module (PK3)
    â€¢ Inflatable restraint sensing and diagnostic module (SDM).
    â€¢ Driver Information Display (DID)
    â€¢ Radio

The Class 2 serial data link allows a scan tool to communicate with the above modules for diagnostic and testing purposes. The Class 2 serial data link is located at the DLC connector terminal 2.