GM Service Manual Online
For 1990-2009 cars only

Data Link Connector (DLC)

The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following:

    • Class 2 serial data at terminal 2
    • Scan tool power battery positive voltage at terminal 16
    • Scan tool power ground at terminal 4
    • Common signal ground at terminal 5

The scan tool will power up with the ignition OFF. Some modules however, will not communicate unless the ignition is ON and the power mode master (PMM) module sends the appropriate power mode message. The PMM on this vehicle is the dash integration module (DIM). Refer to Body Control System Description and Operation in Body Control System.

Class 2 Serial Data Circuit

The data link is configured as a ring with discrete lines entering and leaving each module. This allows communications to the modules on the ring if one of the 2 discrete circuits is open.

A total list of the control modules on the Class 2 Serial Data Circuit can include the following:

    • Dash Integration Module (DIM)
    • Driver Door Module (DDM)
    • Driver Information Center (DIC)
    • Electronic Brake Control Module (EBCM)
    • Inflatable Restraint Sensing and Diagnostic Module (SDM)
    • Instrument Panel Cluster (IPC)
    • Instrument Panel Integration Module (IPM)
    • Memory Seat Module (MSM) w/A45
    • Powertrain Control Module (PCM)
    • Radio
    • Rear Integration Module (RIM)
    • Remote Control Door Lock Receiver (RCDLR)
    • Remote Playback Device - CD Changer w/U1S
    • Theft Deterrent Control Module
    • Vehicle Interface Unit (VIU)

The following modules have only one communication line connection to the Class 2 serial data circuit:

    • Memory Seat Module (MSM)
    • Driver Door Module (DDM)
    • Vehicle Interface Unit (VIU)

Power Door Serial Data Circuit

The power door serial data circuit does not communicate with the scan tool via the DLC. The power door serial data information is interpreted by the driver door module (DDM) and transmitted on the Class 2 data link by the DDM.

The door system serial data circuit is used for serial data communication between the four door modules as well as the driver door switch assembly (DDSA).

Refer to Diagnostic System Check - Door Systems in Doors for diagnosis of the power door serial data circuit.