Circuit/System Description

WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 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. The IAT sensor 2 has a signal circuit and a low reference circuit. The IAT sensor 2 measures the temperature of the air at the engines intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit, and a ground for the IAT sensor 2 low reference circuit. When the IAT sensor 2 is cold, the sensor resistance is high. When the intake manifold air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT sensor 2 signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT sensor 2 signal 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 1.