99VetteFRC

I am using an '03 Silverado engine, PCM, and wiring harness to put in my Chevelle. I have reworked the harness and added a OBDII connector. Unfortunately all my schematics are at work with the engine so I have to wing this. The DLC connector has 2 grounds, a battery positive, 1 bus wire to the PCM and 2 high speed bus wires. I have the power and grounds and the single bus wire hooked up and when I put the scanner on it I can get codes and read data. Will the PCM flash throught the single bus or the 2 wire high speed bus. Here is the kicker, when I trace the schematic the high speed bus pins in the PCM connector are not used. The question is should I repin the PCM connector and connect these wires to DLC or am I good with the single bus wire. Any help would be appreciated.