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 Performance

Diagnostic Fault Information

Typical Scan Tool Data

Circuit/System Description

The intake air temperature (IAT) sensor is integrated with the mass air flow (MAF) sensor. It 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.

Conditions for Running the DTC

* DTCs P0112, P0113, P0117, P0118 are not set.
* The vehicle has been OFF at least 8 hours.
* Vehicle in Service Mode.
* The ECT start-up signal is colder than 60°C (140°F).
* This DTC runs once per ignition cycle when the enabling conditions are met.

Conditions for Setting the DTC

The ECM determines the absolute difference between IAT start-up temperature and the ECT start-up temperature is greater than 40°C (72°F).

Action Taken When the DTC Sets

DTC P0111 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0111 is a Type B DTC.

Diagnostic Aids

* An IAT sensor that is skewed, due to more resistance than is normal, can widen the spread between the 2 sensors and cause this DTC to set. Measure and record the resistance of the 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.
* A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.
* Inspect the mass air flow/intake air temperature sensor terminals for corrosion.

Reference Information
Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation

Hybrid Modes of Operation Description Hybrid Modes of Operation Description
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

Note: Perform Step 1 of this verification procedure only if the vehicle has been OFF for 8 hours or more.

1. Vehicle in Service Mode, observe the following scan tool parameters. The readings should be within 40°C (72°F) of each other.

* Start-Up IAT
* Start-Up ECT

2. Engine running, observe the scan tool IAT sensor parameter. The reading should be between -38 and +149°C (-36 and +300°F), depending on the current ambient temperature and the vehicle operating conditions.
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.

Circuit/System Testing

1. Vehicle OFF, disconnect the harness connector at the B75B mass air flow/intake air temperature sensor.
2. Vehicle OFF, all 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 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. Vehicle in Service Mode, 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.

Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the ECM or the sensor may be damaged.

4. Install a 3 A fused jumper wire between the signal circuit terminal 3 and 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 mass air flow/intake air temperature sensor.

Component Testing

1. Vehicle 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 Temperature Versus Resistance. 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 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