Q: What is the function of the Intake Air Temperature (IAT) sensor and Mass Air Flow Sensor and how to replace?
A: The Intake Manifold Temperature (IMT) sensor is a thermistor, and it changes its resistance according to the temperature. The change in resistance directly affects the voltage signal supplied by the sensor to the PCM. Resistance values decrease as sensor temperature rises and increase when it falls. The IMT is part of the Mass Air Flow sensor, which measures air quantity entering the engine using a hot-wire sensing element. This wire gets cooled as air moves over it. This thermal variation is converted into an analog voltage signal to PCM that adjusts fuel injector pulse width corresponding with airflow. The MAF/IMT can be found on the intake air duct. To replace it, disconnect the sensor electrical connector, remove the two mounting screws and pull the sensor out from the air intake duct. Installation is simply reversing of removal.