Riviera V6-3.8L SC VIN 1 (1995)
Intake Air Temperature Sensor: Description and Operation
PURPOSE
The Intake Air Temperature (IAT) sensor is a thermistor which changes value based on the temperature of air entering the engine. The IAT sensor
signal is used to adjust spark timing according to incoming air density.
OPERATION
Low temperature produces a high resistance (100,000 ohms at 40°C / -40°F), while high temperature causes low resistance (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 measures the voltage. The
voltage will be high when the incoming air is cold, and low when the air is hot. By measuring the voltage, the PCM calculates the incoming air
temperature.
