Continuity was normal while doing wiggle test between ECM and connector 89B so I'm skeptical but Ill persevere on the presumption that wiring is the culprit.

I still have to Ohm wires 7 and 26 which will demonstrate if anything is rubbed out within the main harness somewhere - This would be a the most costly fix :-/

I have checked the calibration for the IAT Sensor and it's within spec (530@160F).

The schematics and manual information you have posted above Bill are critical to the understanding of this issue and any future resolution to DTC P0113 which other members will encounter - my hats off to you and everyone else who have contributed so far :-)