P0111
DTC P0111
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 Descriptor
DTC P0111
- Intake Air Temperature (IAT) Sensor 1 Performance
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air in the sensor bore. The IAT is integrated with the mass air flow (MAF) sensor. The engine control module (ECM) supplies 5 V to the IAT sensor signal circuit and a ground for the IAT sensor low reference circuit. The signal varies with inlet air temperature and is displayed by the scan tool as °C (°F).
Conditions for Running the DTC
* DTCs P0112, P0113, P0117, P0118, P0119, or P1682 are not set.
* The vehicle has been OFF at least 8 hours.
* Ignition 1 voltage is at least 11 V.
* The ignition is ON, or the engine is running.
* The DTCs run continuously when the above conditions are met.
Conditions for Setting the DTC
* The absolute difference between ECT start-up temperature and the IAT sensor start-up temperature is greater than a calibrated temperature.
* This DTC runs once per ignition cycle when the enabling conditions are met.
Action Taken When the DTCs Set
DTC P0111 is a Type B DTC.
Conditions for Clearing the DTCs
DTC P0111 is a Type B DTC.
Diagnostic Aids
* Certain resistance conditions with IAT or ECT sensors may cause unwarranted cooling fan activation. If the ECM is commanding the cooling fans ON for no apparent reason and without any component or system DTCs set, the IAT or ECT sensor may be skewed. Refer to Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor) Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor) or Temperature Versus Resistance (Engine Coolant Temperature Sensor) Temperature Versus Resistance (Engine Coolant Temperature Sensor) tables, if this condition is suspected.
* 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 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 and/or P0114 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 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 (LUK) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
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 running, observe the scan tool IAT Sensor parameter. The reading should be between -40 and +149°C (-40 and +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 mass air flow, intake air temperature sensor.
2. Ignition OFF, all 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 low reference circuit terminal 1 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 OFF, all vehicle systems OFF, test for less than 5 ohms between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
4. 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 for a short to ground. If the circuit tests normal, replace the K20 ECM.
5. Ignition ON. Test for 4.8-5.2 V between the IAT sensor signal circuit terminal 3 and ground.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
Note: If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
6. If all circuits test normal, test or replace the B75B mass air flow, intake air temperature sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the B75B mass air flow, intake air temperature 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 - Intake Air Temperature Sensor (Hitatchi Sensor) Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor) table. The resistance values should be in range of the table values.
• If not within the specified range, replace the B75B mass air flow, intake air temperature sensor.
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 for Mass Airflow Sensor with Intake Air Temperature Sensor replacement.
* Control Module References Control Module References for engine control module replacement, programming, and setup.