Circuit/System Description

The intake air temperature (IAT) sensor is integrated with the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the air when it first enters the induction system. This sensor is also used to calculate ambient air temperature. The engine control module (ECM) supplies 5 volts to the IAT sensor signal circuit and a ground for the low reference circuit.

The intake air temperature (IAT) sensor 2 is integrated with the intake air pressure and temperature sensor. The IAT sensor 2 is a variable resistor that measures the temperature of the air after the turbocharger and the charge air cooler, and before it enters the engine intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit and a ground for the low reference circuit.

The purpose of this diagnostic is to analyze the performance of the 2 sensors by comparing them to each other under various operating conditions to determine if they are within an acceptable temperature range of each other.