DeVille V8-4.9L VIN B (1995)
Intake Air Temperature Sensor: Description and Operation
IAT Location
DESCRIPTION
The Intake Air Temperature (IAT) Sensor is a thermistor (a resistor which changes value based on temperature) mounted in the intake manifold
down stream of the throttle body and measures the air temperature entering the engine. At cold air temperatures, the IAT sensor resistance is high
and at hot air temperatures, the resistance of the sensor is low. The Powertrain Control Module (PCM) supplies a 5 volt reference signal and a
ground to the sensor and measures the voltage signal as it is changed by the sensor. The voltage is close to 5 volts at cold temperatures and close to
zero volts at hot temperatures.
The PCM uses IAT information in conjunction with Manifold Absolute Pressure (MAP) information to determine the density of air entering the
engine. A faulty IAT sensor may cause various driveability conditions and should set a Diagnostic Trouble Code.
