Theory Of Operation
WARNING: This page is about a different car, the 2016 Dodge Durango. However, it is still accessible from the selected car via links, so may be relevant.
The Intake Air Temperature (IAT) Sensor diagnostic, under cold start conditions, following a start to run delay time, compares the outputs of the ambient, engine coolant and intake air temperature sensors. If the Engine Coolant and Ambient Air Temperature Sensors agree and the Intake Air Temperature Sensor does not agree, the Intake Air Temperature Sensor is declared as irrational. If declared irrational a second comparison will be done after a short drive cycle.