Enhanced Testing

P0112 - Intake Air Temperature Flow Circuit Low Input






General Description
The Intake Air Temperature (IAT) sensor measures the temperature of engine intake air. The Intake Air Temperature (IAT) sensor is a thermistor (a variable resistor that changes along with outside air temperature) in series with a fixed resistor in the ECM. The ECM applies 5 volts to the IAT sensor. The ECM monitors the voltage across the IAT sensor and converts it into a temperature reading. When the outside air temperature is cold the IAT sensor resistance is high, and when the outside air temperature is warm the IAT sensor resistance is low. Therefore, when the air temperature is cold the ECM will receive a high voltage input, and when the air temperature is warm the ECM will receive a low voltage input. The signal from IAT sensor is used for injection time correction (cold post start correction), ignition angle correction (air temperature correction) and idle speed correction (air-density correction).

DTC Description
If the value of IAT sensor is lower than threshold, the ECM determines that a fault exists and a DTC is stored.

Detecting Condition and Specification





Wiring Schematic





Signal Waveform