Ranger 2WD V6-182 3.0L (1995)
Intake Air Temperature Sensor: Description and Operation
Intake Air Temperature Sensor
PURPOSE
The Intake Air Temperature (IAT) sensor measures the temperature of the incoming air flow. The Powertrain Control Module (PCM) uses this
information to adjust the fuel injection base pulse width, EGR flow, and ignition timing.
CONSTRUCTION
The IAT is a two lead thermistor type sensor with a negative temperature coefficient. Thermistor type sensors are considered passive sensors. A
passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow.
OPERATION
The PCM applies a 5.0 volt reference voltage to the IAT signal lead while the signal return lead is connected to a common sensor ground. As the
temperature of the incoming air increases the resistance of the IAT decreases and the voltage drop across the IAT decreases.
A decrease in air temperature will increase the resistance of the IAT and raise the voltage drop across the sensor.
The normal operating range of the IAT is 3.50 volts (50°F) to 1.02 volts (158°F).
NOTE: Due to its negative temperature coefficient minor increases in resistance across the IAT circuit harness and ground connections can result
in temperature values that are much lower than actual.
