GM Service Manual Online
For 1990-2009 cars only

Data Link Connector (DLC)

The data link connector (DLC) is a standardized 16-way connector located below the instrument panel and close to the steering column. Both the connector design and location are dictated by industry wide agreement to follow SAE J1962 standards.

All DLCs are required to provide a power supply, hot at all times, to Pin 16. This circuit is used to power the scan tool. All DLCs provide a power ground at Pin 4 and a clean signal ground at Pin 5.

The class 2 serial data communications circuit is provided at Pin 2 of the DLC.

Class 2 Serial Data Link

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

    • Auxiliary power drop connector
    • Body control module (BCM)
    • Digital radio receiver (U2K or U2L)
    • Driver information center (DIC)
    • Electronic brake control module (EBCM)
    • Instrument panel cluster (IPC)
    • OnStar module (UE1)
    • Powertrain control module (PCM)
    • Radio
    • Inflatable restraint sensing and diagnostic module (SDM)

The class 2 serial data link allows a scan tool to communicate with the above modules for diagnostic and testing purposes.