P0113

DTC P0112 or P0113

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) 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, P0502, P0503, P0608, or P0609 are not set.
* The engine run time is greater than 10 seconds.
* The DTC runs continuously when the above conditions are met.



P0113
* DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0502, P0503, P0608, or P0609 are not set.
* The engine run time is greater than 10 seconds.
* The 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 DTC

DTCs P0112 and P0113 are Type B DTCs.


Diagnostic Aids

* With the ignition ON, and 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.



Reference Information
Schematic Reference

Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


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 ohm 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, then compare those measurements to the Temperature Versus Resistance (Temperature Versus Resistance) table.


Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.

* Mass Airflow Sensor/Intake Air Temperature Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming