Circuit Description

Intake Air Temperature (IAT) sensor contains a thermistor which changes resistance based on temperature. IAT sensor is located in air intake passage. Sensor has a signal and ground circuit. ECM applies about 5 volts on sensor signal circuit. ECM monitors changes in voltage caused by changes in resistance of sensor to determine intake air temperature.

When intake air is cold, sensor resistance is high. ECM will sense a high signal voltage (low temperature). When intake air is warm, sensor resistance is low. ECM will sense a low signal voltage (high temperature). When ECM senses a signal voltage outside normal operating range of sensor, this DTC will set.

Conditions required to set DTC are:

• IAT signal voltage indicates an intake air temperature greater than 282°F (139°C) or less than -45°F (-43°C).
• Conditions are met for at least 10 seconds.