Powertrain Management (Without Heavy Duty)

DTC P0112 or P0113 (Without Heavy Duty L96)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions 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 Description

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

The following table illustrates the difference between temperature, resistance, and voltage:

Conditions for Running the DTC

P0112

* DTCs P0117, P0118 are not set.

* The engine is running for greater than 10 s.

* The engine coolant temperature (ECT) is colder than 150°C (302°F).

* This DTC runs continuously when the above conditions are met.

P0113

* DTCs P0101, P0102, P0103, P0117, P0118 are not set.

* The engine is running for greater than 10 s.

* The ECT is warmer than -40°C (-40°F).

* The MAF Sensor signal is equal to or 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 signal is warmer than 149°C (300°F) for greater than 5 s.

P0113

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

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.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Engine idling, observe the scan tool IAT Sensor parameter. The reading should be between -38 to +149°C (-36 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 to verify that the DTC does not reset. 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 MAF/IAT sensor.

2. Ignition OFF, all vehicles systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the IAT low reference circuit terminal A and ground.

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

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

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

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

• If colder than the specified range, test the IAT 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 MAF/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 Versus Resistance Temperature Versus Resistance table.

Repair Instructions

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

* Mass Airflow Sensor with Intake Air Temperature Sensor Replacement Service and Repair

* Control Module References Control Module References for ECM replacement, programming, and setup