P0113
DTC P0112, P0113, or P0114 (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
DTC P0114
- Intake Air Temperature (IAT) Sensor Circuit Intermittent
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
* The engine is running.
* This DTC runs continuously when the above conditions are met.
P0113
* The engine is running.
* This DTC runs continuously when the above conditions are met.
P0114
* The ignition is ON or the engine is running.
* This DTC runs continuously within the enabling conditions.
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
Note: The scan tool display range is between -40 and + 150°C (-40 and +302°F).
The ECM detects that the IAT sensor signal is colder than -59°C (-72°F) for greater than 5 s.
P0114
The ECM detects that the IAT sensor signal is intermittent or has abruptly changed greater than 10°C (18°F).
Action Taken When the DTC Sets
DTCs P0112, P0113 and P0114 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0112, P0113 and P0114 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 and/or a DTC P0114 to set.
* A MAF sensor ground circuit that is open will cause a DTC P0113 and/or a DTC P0114 to set.
Reference Information
Schematic Reference
Engine Controls Schematics (except L96) [1][2]Electrical DiagramsEngine Controls Schematics (L96) [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 B75B 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 ohm 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 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 IAT signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 ECM.
Note: If the fuse in the jumper opens, the signal circuit is shorted to voltage and the sensor may be damaged.
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 K20 ECM.
5. If all circuits test normal, test or replace the B75B MAF/IATT sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the IAT sensor.
Note: A thermometer can be used to test the sensor off the vehicle.
2. Test the IAT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance Temperature Versus Resistance
• If not within the specified range, replace the IAT sensor.
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