GM Service Manual Online
For 1990-2009 cars only

The Data Link Connector (DLC) contains these serial data links:

    • Class II.
    • UART.
    • Entertainment and Comfort (E&C).

The DLC also provides a power source for the scan tool:

    • Unswitched voltage (B+) at DLC terminal 16 (circuit 640).
    • Ground at terminals 4 (circuit 1450) and 5 (circuit 1550).