Data Link Connector

WARNING: This page is about a different car, the 2001 GMC Safari and 2001 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.

Data Link Connector (DLC) allows a scan tool to communicate with class 2 serial data circuit. DLC is a standardized 16-pin connector located below left side of instrument panel. Both connector design and location are dictated by industry wide agreements. All DLCs are required to provide a power supply, hot at all times, to terminal 16. This circuit is used to power scan tool. All DLCs supply a power ground at terminal 4 and a signal ground at terminal 5. Class 2 serial data circuit is provided at terminal 2 of DLC. Once scan tool is connected to class 2 serial data circuit through DLC, scan tool can be used to monitor each module for diagnostic purposes and to check for DTCs. Each module is assigned a specific recognition code known as source ID. This code is used to identify which module is communicating on serial data circuit. When a message is sent out on serial data circuit, recognition code will identify which particular module sent message. These messages contain specific information, or commands, modules require to function properly. When a module receives a message it also "learns" source ID of module that sent it.

Class 2 serial data circuit allows these modules to communicate data with each other:

Body Control Module (BCM).
Driver Information Center (DIC).
Electronic Brake Control Module (EBCM).
Instrument Panel Cluster (IPC).
Powertrain Control Module (PCM).
Inflatable Restraint Sensing and Diagnostic Module (SDM).
Transfer Case Shift Control Module (TCSCM).

In addition, class 2 serial data circuit allows a scan tool to communicate with these modules for diagnostic and testing purposes.