Code P0112, IAT Sensor Circuit Low Temperature Indicated: Notes

Intake Air Temperature (IAT) sensor is a thermistor. PCM applies and monitors a 5-volt reference signal to sensor. When air is cold, sensor resistance is high and PCM will measure a high signal voltage. If air is warm, sensor resistance is low causing PCM to measure low voltage.

Code P0112 will set when the following conditions are present.

• Engine coolant temperature is greater than 140°F (60°C).
• Mass airflow is less than 12 grams per second.
• Vehicle speed is less than 25 MPH.
• IAT signal voltage indicates an intake air temperature less than about -29°F (-34°C) for 5 seconds.
  NOTE: Test numbers refer to numbers on diagnostic chart.

1. An open sensor, wire or connection will cause Code P0112 to set. An open circuit would cause scan tester to display about -40°C. This test determines if wiring and PCM are okay.