The function diagram for the IAT sensor includes the following:
• IAT sensor
• Electronic Control Module (ECM)
• Fuel injector
• ENGINE lamp (amber)
Function
The Intake Air Temperature (IAT) sensor is a thermistor sensor that is chassis mounted on the air filter housing. The ECM supplies a 5 V reference signal which the IAT sensor uses to produce an analog voltage that indicates the intake air temperature.
The IAT sensor changes resistance when exposed to different temperatures.
As air temperature decreases, the resistance of the thermistor increases.
This causes the signal voltage to increase. As air temperature increases, the resistance of the thermistor decreases. This causes the signal voltage to decrease.
The IAT sensor provides a feedback signal to the ECM indicating intake air temperature. The ECM monitors
the IAT signal to control the timing and fuel rate for cold starting. The continuous monitoring by the IAT sensor limits smoke emissions.
