I have a 2008 Chevrolet Cobalt LT. I started researching making my own bench harness but that led me to finding the GODIAG GT100 device. It allows you to connect to any PCM/ECM outside of the vehicle. This is useful for ECM troubleshooting, diagnostics, coding and programming. I'm not sure how much I will use it but certainly useful for my current set of problems. Worked like a charm. For reference, I connected 12v power leads to pins 3,19, 20 and 73, CAN- to 43 and CAN+ to 44 on J1 and ground to pin 73 in J2 (2008 ECM). Connect scanner to OBD2 and bam, I'm able to pull codes and read information directly from the ECM. Hope it helps someone out there!