P0114
DTC P0112, P0113, or P0114
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/System Description
The sensors listed below are integrated within the mass air flow/multifunction intake air sensor:
* IAT sensor 1
* IAT sensor 2
* Humidity sensor
* MAF sensor
* BARO pressure sensor
The intake air temperature (IAT) sensor 1 is a variable resistor that changes the voltage on the engine control module (ECM) supplied 5 V signal circuit. The signal varies with inlet air temperature in the sensor bore and is displayed by the scan tool as °C (°F).
The sensors listed below share an ECM supplied 5 V reference circuit:
* IAT sensor 2
* Humidity sensor
* BARO pressure sensor
The sensors listed below share an ECM supplied low reference circuit:
* IAT sensor 1
* IAT sensor 2
* Humidity sensor
* Barometric pressure (BARO) sensor
Conditions for Running the DTCs
P0112, P0113, and P0114
* The ignition is ON, or the engine is running.
* The DTCs run 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 at least 5 s.
P0113
The ECM detects that the IAT sensor signal is colder than -60°C (-76°F) for at least 5 s.
Note: The scan tool display range is between -40 and +150°C (-40 and +302°F).
P0114
The ECM detects that the IAT sensor signal is intermittent or has abruptly changed for at least 5 s.
Action Taken When the DTCs Set
* DTCs P0112, P0113, and P0114 are Type B DTCs.
* The ECM commands the cooling fans ON.
Conditions for Clearing the DTCs
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 1 will gradually increase the scan tool IAT Sensor 1 parameter. This is due to the heat that is generated by the MAF sensor heating elements.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Outside Rearview Mirror - Driver
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
Note: To minimize the effects of residual engine heat and sensor internal heating elements, perform Steps 1 and 2 of this verification procedure only if the ignition has been OFF for 8 hours or more.
1. Ignition ON, verify the following scan tool parameters are within 30°C (54°F) of each other.
* Start-Up IAT Sensor 1
* IAT Sensor 2
* IAT Sensor 3
• If not within 30°C (54°F)
Refer to Circuit/System Testing.
• If within 30°C (54°F)
2. Engine idling, verify the following scan tool parameters are between: -38 and +149°C (-36 and +300°F).
* IAT Sensor 1
* IAT Sensor 2
• If not between: -38 and +149°C (-36 and +300°F)
Refer to Circuit System Testing.
• If between: -38 and +149°C (-36 and +300°F)
3. 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.
4. Verify the DTCs do not set.
• If any of the DTCs set
Refer to Circuit/System Testing.
• If none of the DTCs set
5. All OK
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B75C Mass Air Flow/Multifunction Intake Air sensor (IAT Sensor 1).
2. Ignition OFF and all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 2 ohms between the low reference circuit terminal 7 and ground.
• If 2 ohms or greater
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open or high resistance in the circuit.
• If less than 2 ohms replace the K20 Engine Control Module.
• If less than 2 ohms
3. Ignition ON, test for 4.8-5.2 V between the intake air temperature sensor 1 signal circuit terminal 8 and ground.
• If less than 4.8 V
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If greater than 5.2 V
Note: If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Ignition ON, test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If between 4.8-5.2 V
4. Test or replace the B75C Mass Air Flow/Multifunction Intake Air sensor (IAT Sensor 1).
Component Testing
Mass Air Flow/Multifunction Intake Air Sensor (IAT Sensor 1)
1. Ignition OFF, disconnect the harness connector at the B75C Mass Air Flow/Multifunction Intake Air sensor.
Note: A thermometer can be used to test the sensor off the vehicle.
2. Test the IAT sensor 1 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance - Intake Air Temperature Sensor (Delco Sensor) SpecificationsTemperature Versus Resistance - Intake Air Temperature Sensor (Bosch) Specifications table for Bosch Sensors. The resistance values should be in range of the table values.
• If not within the specified range, replace the B75C Mass Air Flow/Multifunction Intake Air sensor (IAT Sensor 1).
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Mass Airflow Sensor Replacement Service and Repair for mass air flow/multifunction intake air sensor (IAT Sensor 1) replacement.
* Control Module References Control Module References for engine control module replacement, programming, and setup.