Prizm L4-108 1.8L DOHC VIN 8 MFI (1998)
Intake Air Temperature (IAT) Sensor: Description and Operation
Intake Air Temperature (IAT) Sensor
The intake air temperature (IAT) sensor (2) is mounted in the air cleaner assembly and connected to the PCM with a harness connector (1). The AT
sensor measures the temperature of the air entering the intake manifold and provides this information to the powertrain control module (PCM).
The IAT sensor is a thermistor (a resistor whose resistance changes as a function of temperature). When the temperature is low, the resistance is high.
The resistance decreases as temperature increases. The IAT sensor is a two-wire sensor with a reference or signal voltage and a ground coming from the
PCM.
The IAT sensor provides intake air temperature information to the PCM for use in calculating air density. The PCM uses IAT, MAP and engine speed in
order to calculate the quantity of air flowing into the engine.