P0112

DTC P0112, P0113, or P0114

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

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

DTC P0113
- Intake Air Temperature (IAT) Sensor Circuit High Voltage

DTC P0114
- Intake Air Temperature (IAT) Sensor Circuit Intermittent

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The intake air temperature (IAT) sensor is integrated with the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the air when it first enters the induction system. The engine control module (ECM) supplies 5 volts to the IAT sensor signal circuit and supplies a ground to the low reference circuit.

Conditions for Running the DTC

P0112
* The ignition is ON or the engine is running.
* This DTC runs continuously within the enabling conditions.

P0113
* The engine is running.
* This DTC runs continuously within the enabling conditions.

P0114
* The ignition is ON or the engine is running.
* This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

P0112

The ECM detects that the IAT is greater than 131°C (268°F) for greater than 15 seconds at idle.

P0113

The ECM detects that the IAT is less than -39°C (-38°F) for greater than 15 seconds at idle.

P0114

The ECM detects that the IAT sensor signal is intermittent or has abruptly changed for greater than 4 seconds.

Action Taken When the DTC Sets

DTCs P0112, P0113, P0114 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0112, P0113, P0114 are Type B DTCs.

Diagnostic Aids

* If the engine is cold, then at ignition ON, a properly functioning IAT sensor will gradually increase the scan tool IAT Sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements.
* Depending on the ambient temperature, an IAT sensor signal circuit that is shorted to the MAF sensor signal circuit can cause a DTC P0113 and/or a DTC P0114 to set. This condition may cause either a rapid fluctuation in the IAT Sensor parameter or cause it to become stuck at a given value.
* An IAT low reference circuit that is open can cause the IAT Sensor parameter response to be sluggish. This condition may not necessarily set a DTC.
* A MAF sensor ground circuit that is open will cause a DTC P0113 and/or a DTC P0114 to set.

Circuit/System Verification

Important: Determine the ambient temperature by using an accurate thermometer.

* If the ignition has been OFF for 8 hours or greater, the IAT, the IAT 2 and the engine coolant temperature (ECT) should be within 9°C (16°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool IAT Sensor, IAT 2 Sensor and the ECT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the condition is current.
* Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.

Circuit/System Testing

1. Ignition OFF, disconnect the MAF/IAT harness connector at the MAF/IAT sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the MAF sensor ground circuit and ground.

• If greater than the specified range, test the MAF sensor ground circuit for an open/high resistance.

3. Ignition OFF, test for less than 5 ohms of resistance between the IAT low reference circuit and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

4. Ignition ON, verify the scan tool IAT Sensor parameter is less than -39°C (-38°F).

• If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

5. Install a 3A fused jumper wire between the signal circuit and a good ground. Verify the scan tool IAT Sensor parameter is greater than 131°C (268°F).

• If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal replace the ECM.

6. If the circuits test normal, test the IAT sensor.

Component Testing

Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Mass Airflow Sensor Replacement
* Refer to Programming and Relearning for ECM setup and programming. Programming and Relearning