Hi,
The P0072 indicates an issue with the ambient air temperature sensor. (See pic 1 below)
When you had the computer scanned, was the scanner able to read codes from the can-bus? The codes we have are specific to the engine management and not transmission.
As far as the transmission, since it started when you switched relays, recheck the transmission control relay. Make sure none of the pins in the relay box have been pushed in or are damaged. Also, confirm fuse 15 is good and has power.
If you want, here is a link that explains how to test a relay:
https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit
Let me know what you find.
Joe
See pics below Pics 2 and 3 are the wiring schematic for the transmission. I had to cut it in half to make it readable, but I did overlap them so you can follow from one to the next.
Images (Click to make bigger)
Saturday, November 27th, 2021 AT 10:26 PM