Intake Air Temperature Sensor (IAT)
WARNING: This page is about a different car, the 2004 Ford RV Cutaway, 2004 Ford Econoline, 2004 Ford E450 Super Duty, and 2004 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The intake air temperature (IAT) sensor is a thermistor in which resistance changes with temperature. The electrical resistance decreases as the temperature increases. The IAT provides air temperature information to the powertrain control module (PCM) which is used to help determine transmission line pressure and shift scheduling.