P0112

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The intake air temperature sensor is a thermistor (a variable resistor) that measures the temperature of the air entering the engine. The PCM supplies 5 volts to the AT signal circuit through a pull-up resistor. When the intake air is cold, the PCM detects a high voltage on the IAT signal circuit. As the intake air warms, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively low IAT signal voltage (high temperature indicated), DTC P0112 will set.

CONDITIONS FOR RUNNING THE DTC
^ ECT sensor, MAF sensor, or VSS DTCs are not set.
^ Engine has been running for at least 10 seconds.
^ Engine coolant temperature is below 100°C (212°F).
^ Vehicle speed is more than 15 km/h (9 mph).

CONDITIONS FOR SETTING THE DTC
^ The IAT sensor signal voltage is less than 0.08 volt. This would be approximately 137°C (278°F).
^ The condition exists for less than 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
For intermittent conditions, refer to DTC P1112 Intake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage and/or Symptoms. P1112 Symptom Related Diagnostic Procedures