Data Link Connector (DLC)
WARNING: This page is about a different car, the 2020 Buick Regal and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
The data link connector (DLC) provides serial data communication for ECM diagnosis. This connector allows the technician to use a scan tool in order to monitor various serial data parameters, and display DTC information. The DLC is located inside the driver's compartment, underneath the instrument panel.