Retrieving DTCs Using Scan Tool
WARNING: This page is about a different car, the 1999 Cadillac Eldorado and 1999 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Scan tool can read IPC inputs and outputs. See scan tool manufacturer's instructions