GM Service Manual Online
For 1990-2009 cars only

The Data Link Connector (DLC) is a multiple cavity connector. During diagnosis, the technician accesses serial data by means of the DLC. The DLC allows the technician to use a scan tool in order to monitor various systems (parameters) and to display DTC codes. The DLC connector is located within the driver's compartment, normally on the left side near the steering column.