P0113

DTC P0112 or P0113

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

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit.

Conditions for Running the DTC

P0112
* DTCs P0116, P0117, P0118, P0128, P0502, P0503 are not set.
* The engine is running for greater than 10 seconds.
* The engine coolant temperature (ECT) is less than 150°C (302°F).
* This DTC runs continuously when the above conditions are met.

P0113
* DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0128, P0502, P0503 are not set.
* The engine is running for greater than 10 seconds.
* The ECT is more than -40°C (-40°F).
* The MAF Sensor parameter is greater than 512 g/s.
* This DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0112

The ECM detects that the IAT sensor parameter is warmer than 149°C (300°F) for greater than 5 seconds.

P0113

The ECM detects that the IAT sensor parameter is colder than -39°C (-38°F) for greater than 5 seconds.

Action Taken When the DTC Sets

DTCs P0112 and P0113 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0112 and P0113 are Type B DTCs.

Diagnostic Aids

* With the ignition ON, the engine OFF, if the engine is cold, 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 mass air flow (MAF) sensor heating elements.
* Depending on the ambient temperature, an IAT sensor signal circuit or low reference circuit that is shorted to the MAF sensor signal circuit can cause a DTC P0113 to set. This condition causes a rapid fluctuation in the IAT Sensor parameter.
* An IAT sensor signal circuit that is shorted to the MAF sensor ignition circuit can cause a DTC P0113 to set.

Circuit/System Verification

1. Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -38 to +149°C (-38 to +300°F) depending on the current ambient temperature and the vehicle operating conditions.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the IAT sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal E 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.

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

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

4. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool IAT parameter is greater than 149°C (300°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.

5. If all circuits test normal, test or replace the IAT sensor.

Component Testing

Measure and record the resistance of the IAT sensor at various ambient temperatures, and 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/Intake Air Temperature Sensor Replacement