After an overnight cold soak, use a scan tool and access vehicle data stream and see what they read before starting your engine. They should be within a few degrees of the other. and that should be close to your ambient temperature. The ECM doesn't set a code for them unless they fail open or read higher than operating parameters.
I did it this morning. Do these numbers look correct? Any feedback would be appreciated.
Before starting this morning:
Ambient temp: 66F
Fwiw, I noticed while driving steadily at 65mph, the IAT would fluctuate slowly between 62-77. Despite ambient temp staying the same.
The coolant was fairly steady between 188-192. Thermostat is a new 192 motorcraft.