Circuit/System Description

The intake air temperature (IAT) sensor 3 is a variable resistor that changes an engine control module (ECM) supplied 5 V signal. The signal varies with inlet air temperature and is displayed by the scan tool as °C (°F). The IAT sensor 3 is integrated with the B111B Turbocharger Boost/Intake Air Temperature Sensor in the sensor bore, which is located before the throttle body. The ECM supplies a ground for the IAT sensor 3 low reference circuit.

The IAT sensor 1 and IAT sensor 2 are part of the B75C Multifunction Intake Air Sensor. The IAT sensor 1 produces an analog signal on pin-8 of the sensor. The IAT sensor 2 produces a frequency modulated signal on pin-1 of the sensor.