Rodeo LS 4WD V6-3.2L (1998)
Intake Air Temperature Sensor: Description and Operation
DESCRIPTION AND OPERATION
The intake air temperature (IAT) sensor is a thermistor which changes its resistance based on the temperature of air entering the engine. Low
temperature produces a high resistance of 100,000 ohms at -40°C (-40°F). High temperature causes low resistance of 70 ohms at 130°C (266°F).
The Powertrain Control Module (PCM) supplies a 5-volt signal to the sensor through a resistor in the PCM and monitors the signal voltage. The
voltage will be high when the incoming air is cold. The voltage will be low when the incoming air is hot. By measuring the voltage, the PCM
calculates the incoming air temperature. The IAT sensor signal is used to adjust spark timing according to the incoming air density.
The scan tool displays the temperature of the air entering the engine. The temperature should read close to the ambient air temperature when the
engine is cold and rise as underhood temperature increases. If the engine has not been run for several hours (overnight), the IAT sensor
temperature and engine coolant temperature should read close to each other. A failure in the IAT sensor circuit will set DTC P0112 or DTC
P0113.