If the code says circuit high, it is reading 5Volts, which means that the circuit is open(or disconnected).
I would check your connector to your IAT sensor and make sure it is plugged in. Then I would inspect your harness for any damage. If it is all ok, I would replace your IAT sensor.
I hope this helps, let me know if you have any more questions!
Here it is:
I hope this helps, feel free to ask if you need anything else!