OBD2 direct pinout connections to ECM on C6 corvette

I am new to this system. I am trying to communicate with an ECM from a 2011 Corvette on a bench. This OBD2 uses the following pins:


Pin 2 - Purple wire - Serial Data (original wiring sends this to the JX205 and MX208 harnesses adjacent to steering wheel

Pin 4 - Black wire - Ground wire connection at left door pillar

Pin 5 - Black/white wire - Ground wire at frame next to battery

Pin 6 - Tan/black wire - High-speed GMLAN serial data (+) at body control module

Pin 14 - Tan wire - High-speed GMLAN serial data (-) at body control module

Pin 16 - Red/white wire - +12 Volts hot



Since I am trying a bench setup, the High-speed serial data wires have been soldered from the OBD2 plug directly to the tan wire at X1 ECM plug at pin 27 and the tan/black wire at X1 ECM plug at pin 28. I don't know the location for the purple wire for serial data.


I know the scanner works, because I plugged into my Denali truck OBD2 and was instantly communicating. So, what is necessary for the bench setup that I am missing.


Thanks,
John B

Attachment 86310

An update on previous message. I have not connected wire #2 to anything, since I can't find a pin on the ECM to accept it. I do get a brief attempt of communicating between MPVI2 and the ECM. Then, this message appears. What do I do next?

Got it working. My problem was a break in my black/tan wire. Tinned and soldered the break, a short piece of shrink tube, and all is well.