P0112

DTC P0112 Intake Air Temperature (IAT) Sensor Circuit Low Voltage






Circuit Description

The Intake Air Temperature (IAT) sensor is a thermistor that controls signal voltage to the PCM. When the air is cold, the sensor resistance is high, therefore the PCM Will see a high signal voltage. As air warms, sensor resistance becomes less and voltage drops.

Conditions for Setting the DTC

^ Engine coolant temperature less than 42.5°C (1O9°F).
^ Intake air temperature greater than or equal to 151°C (303°F).
^ Conditions met for 2 seconds.

Action Taken When the DTC Sets

A possible poor performance problem may exist during cold weather operation.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL off after three consecutive trips without a fault condition.
^ A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 16O°F (71°C) that same ignition cycle).
^ Use of a Scan Tool

Diagnostic Aids

Check harness routing for a potential short to ground in the signal circuit. Scan Tool displays intake air temperature in degrees centigrade. A "skewed" sensor could result in poor driveability complaints.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

3. This step determines if P0112 is a hard failure or an intermittent condition.

4. This test will determine if the PCM can recognize an open sensor.

5. This step will determine if the problem is a short to ground or a malfunctioning PCM.