Scan Tool Does Not Power Up: Description
WARNING: This page is about a different car, the 2001 Cadillac Seville, 2001 Cadillac Eldorado, and 2001 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Data Link Connector (DLC) provides operating power for scan tool through terminal No. 16 (Orange wire) and ground through terminal No. 4 (Black wire). DLC provides class 2 serial data signal through terminal No. 2 (Purple wire) and ground through terminal No. 5 (Black/White wire). Scan tool will power up with ignition off.