GM Service Manual Online
For 1990-2009 cars only

The Data Link Connector (DLC) contains the following components:

    • The UART serial data line circuit which allows a scan tool to communicate with the following modules for diagnostic and testing purposes:
      • The Electronic Brake Control Module (EBCM) (if equipped with JL9 or JM4)
      • The SDM
    • The Class 2 serial data line circuit which allows a scan tool to communicate with the PCM for diagnostic and testing purposes.