Code P038, Open Intake Air Temperature (IAT) Sensor: Notes
WARNING: This page is about a different car, the 1995 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. Code P038 sets when PCM sees low voltage signal when coolant sensor temperature is 14°F (-10°C) or greater.