Pcm Code P038 - Open Intake Air Temp (IAT) Sensor Signal: Notes
WARNING: This page is about a different car, the 1993 Cadillac Seville and 1993 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
IAT sensor is a thermistor that varies its resistance based on temperature. As temperature of sensor decreases, sensor resistance increases. PCM Code P038 sets when PCM sees low voltage signal when coolant sensor temperature is 23°F (-5°C) or greater.