P0112
DTC P0112 or P0113
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/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 5V to the IAT signal circuit, and a ground for the IAT low reference circuit.
Conditions for Running the DTC
P0112
* DTC P0116 or P0117 is not set.
* The engine run time is greater than 10 seconds.
* The DTC runs continuously when the above conditions are met.
P0113
* DTC P0101, P0102, P0103, P0116, P0117 or P0118 is 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
* Ignition ON, 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
Computers and Control Systems Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
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
Programming and Relearning (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition OFF for 8 hours or greater.
2. Ignition ON, observe the scan tool IAT and ECT sensor parameters. The ECT, IAT, and ambient temperatures should be within 15°C (27°F) of each other.
3. 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
Note: All modules must be powered down or misdiagnosis may result.
1. Ignition OFF, disconnect the scan tool and wait 60 seconds to ensure all modules are powered down.
2. Ignition OFF, disconnect the harness connector at the IAT sensor.
3. 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.
4. Ignition ON, verify the scan tool IAT parameter is colder than -39°C (-38°F).
• If warmer than the specified range, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the ECM.
5. Install a 3A fused jumper wire between the signal circuit terminal D and a good ground. Verify the scan tool IAT parameter is warmer than 149°C (300°F).
• If colder 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 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 with Intake Air Temperature Sensor Replacement (Service and Repair)
* Programming and Relearning (Programming and Relearning) for ECM replacement, setup, and programming