GM Service Manual Online
For 1990-2009 cars only

Data Link Communications Circuit Description for Oldsmobile Bravada 2000

The data link connector (DLC) provides operating power for the scan tool at terminal 16 (battery positive voltage) and terminal 4 (ground). The DLC provides the class 2 serial data signal at terminal 2 and signal ground at terminal 5. The scan tool will power up with the ignition off.

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for state of health monitoring (Node Alive Messages).