Circuit/System Description
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The intake air temperature (IAT) sensor 2 is a variable resistor that measures the temperature of the air in the engine intake manifold. The engine control module (ECM) supplies 5V to the IAT sensor 2 signal circuit, and a ground for the IAT sensor 2 low reference circuit. The ECM continuously monitors the IAT sensor 2 signal voltage for an excessively high or low voltage, or a voltage signal that is not in correlation with the engine coolant temperature (ECT) sensor.