Circuit Description

Intake Air Temperature (IAT) sensor is a thermistor in series with a fixed resistor in PCM. PCM applies 5 volts to IAT sensor. PCM monitors voltage across IAT sensor and converts it into a temperature reading. When air temperature is cold, IAT sensor resistance is high (PCM monitors high voltage input). When air temperature is warm, IAT sensor resistance is low (PCM monitors low voltage input).

DTC will set when engine is running and IAT sensor input indicates a smaller change than expected in voltage input during warm-up cycle.