Ambient Air Temperature Sensor
WARNING: This page is about a different car, the 2015 Ford Fiesta. However, it is still accessible from the selected car via links, so may be relevant.
The Ambient Air Temperature (AAT) sensor is an input to the IPC. The Ambient Air Temperature (AAT) sensor contains a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises.