P0113
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, a part of the mass air flow (MAF) sensor assembly, 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 V to the IAT signal circuit, and a ground for the IAT low reference circuit.
Conditions for Running the DTC
P0112
* DTCs P0117, P0118, P0722, P0723 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, P0722, P0723 are not set.
* The engine is running for greater than 10 s.
* The ECT is warmer than -40°C (-40°F).
* The MAF Sensor parameter is less 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 is warmer than 150°C (302°F) for greater than 5 s.
P0113
The ECM detects that the IAT 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 (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
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 +120°C (-38 to +248°F), depending on current ambient temperature and vehicle operation conditions.
2. Operate the vehicle with 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
Note: All electrical components and accessories must be turned OFF and allowed to power down.
1. Ignition OFF, disconnect the IAT harness connector at the B75B MAF/IAT sensor.
2. Ignition OFF, all vehicle systems OFF, this may take up to 2 min, test for less than 5 ohm between the low reference circuit terminal D 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 K20 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 signal circuit terminal E for a short to ground. If the circuit tests normal, replace the K20 ECM.
4. Install a 3 A fused jumper wire between the signal circuit terminal E and a good ground. Verify the scan tool IAT Sensor 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 K20 ECM.
5. If all circuits test normal, test or replace the B75B MAF/IAT sensor.
Component Testing
Measure and record the resistance of the B75B IAT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs Resistance Table. Refer to Temperature Versus Resistance (Temperature Versus Resistance).
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 (Programming and Relearning) for ECM replacement, setup, and programming