Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The data link connector (DLC) provides operating power for the scan tool at terminal 16 (battery positive voltage) and at terminal 4 (ground). The DLC provides the class 2 serial data signals at terminal 7. The scan tool will power up with the ignition OFF. Many modules, however, will not communicate unless the DIM detects that the ignition is ON and sends the appropriate power mode message.