Problem:Vehicle came into the shop with a crank, no-start problem. The malfunction indicator lamp was not illuminated.
Details: The technician tried to connect a scan tool to look at PID information and to retrieve diagnostic trouble codes from various modules, but could not communicate with the ECM. He checked for battery power and ground at ECM. There was no power at pins 110 and 112. Next, he checked for battery power at the ECM relay on the two white/blue wires and red/black wire. He found power to red/black but no power to either white/blue wire. The power comes from fuse #36. He checked that fuse and it was good and had power to it. Next, he checked for open circuit between fuse #36 and ECM relay.
Confirmed Repair: The technician found that the white/blue wire was badly corroded in the harness at firewall (see image). He repaired the wire and the engine started right up.