Code P038, Open Intake Air Temperature (IAT) Sensor: Notes
WARNING: This page is about a different car, the 1995 Cadillac DeVille. 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. High temperature will result in low signal voltage. Code P038 sets when PCM sees low voltage signal when coolant temperature is 23°F (-5°C) or greater.