P0112

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The Intake Air Temperature (IAT) sensor is a thermistor that controls the 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 the air warms, the sensor resistance becomes less and the voltage drops. This is a type B DTC.

CONDITIONS FOR SETTING THE DTC
^ The engine coolant temperature is less than 42.5°C (109°F).
^ The intake air temperature is greater than or equal to 151°C (304°F).
^ The conditions were 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 Malfunction Indicator Lamp (MIL) off after three consecutive trips without a fault condition.
^ A History DTC will clear after forty consecutive warm-up cycles during which the diagnostic does not fail (the coolant temperature has risen 5°C (40°F) from the start up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle).
^ Use of a Scan Tool will clear the DTC codes.

DIAGNOSTIC AIDS
Check harness routing for a potential short to ground in the signal circuit. Scan Tool displays intake air temperature in degrees centigrade. Refer to Intermittents. - Intermittent Malfunctions

A skewed sensor could result in poor driveability complaints. Refer to Temperature vs Resistance. Specifications

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the Diagnostic Table.
2. This step determines if P0112 is a hard failure or an intermittent condition.
3. This test will determine if the PCM can recognized an open sensor.
4. This step will determine if the problem is a malfunctioning PCM or the signal wire is shorted to ground. The normal resistance across the IAT sensor connector harness is 4000-5000 ohms.