Intake Air Temperature Sensor

The Intake Air Temperature (IAT) sensor is a thermistor (variable resistor) wired in series with a fixed resistor inside PCM. IAT sensor measures temperature of outside air entering intake manifold. IAT sensor resistance changes with respect to intake air temperature. High intake air temperature decreases IAT sensor resistance. Low intake air temperature increases IAT sensor resistance.

Sensor resistance modifies a reference voltage that is supplied and monitored by PCM. PCM uses this information to calculate intake air density. See Figure, Figure or Figure .