Test A: Scan Tool Does Not Power Up: Description
WARNING: This page is about a different car, the 2002 Pontiac Grand Am and 2002 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.
The Data Link Connector (DLC) provides operating power for scan tool through IPC/HVAC BATT fuse at terminal No. 16 (battery positive voltage) and ground at terminal No. 4. DLC provides Class 2 serial data signal at terminal No. 2 and signal ground at terminal No. 5. Scan tool will power up with ignition switch in OFF position. Many modules, however, may not communicate unless ignition switch is in RUN position.