P0111

DTC P0111 (LUW)

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 P0111
- Intake Air Temperature (IAT) Sensor Performance

Circuit/System Description

The intake air temperature (IAT) sensor 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

* DTCs P0112, P0113, P0117, or P0118 are not set.

* The engine coolant temperature (ECT) sensor is at power up less than 60°C (140°F).

* The time between current ignition cycle and the last time the engine was running is greater than 8 h.

* The DTC runs once per ignition cycle at engine start when the above conditions are met.

Conditions for Setting the DTC

The ECM detects an IAT sensor that has stuck in range by comparing to engine coolant temperature at startup. The difference between the two sensors should not be greater than 40°C (104°F).

Action Taken When the DTC Sets

DTC P0111 is a Type B DTCs.

Conditions for Clearing the DTC

DTC P0111 is a Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Description and Operation

Air Intake System Description Air Intake System 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 Control Module References for scan tool information

Circuit/System Verification

Note:

* Perform Step 2 of this verification procedure only if the engine has been OFF for greater than 8 h.

* The vehicle sitting in direct sun light or having the block heater ON will skew the results.

1. Verify that DTC P0112, P0113, or P0114 is not set.

• If a DTC is set, refer to DTC P0112, P0113, or P0114 (LUW) P0112.

2. Ignition ON, observe the following scan tool parameters. The readings should be within 40°C (104°F) of each other.

* Start-Up IAT Sensor

* Start-Up ECT Sensor

3. Engine idling, verify the appropriate scan tool parameters are within the specified ranges. The readings depend on the current ambient temperature and the vehicle operating conditions.

* -39 to +149°C (-38 to +300°F); IAT Sensor

* -39 to +139°C (-38 to +282°F); ECT

4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from 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 vehicles systems OFF. It may take up to 2 min 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 Engine Control Module.

3. Ignition ON, verify the scan tool IAT Sensor is at -40°C (-40°F).

• If warmer than the specified range, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

Caution:
If the fuse in the jumper wire opens, the signal circuit may have a short to a voltage or a short to ground and the sensor might be damaged.

4. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool IAT Sensor is at 140°C (284°F).

• If less 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 Engine Control Module.

5. If all circuits test normal, test or replace the B75B Mass Air Flow/Intake Air Temperature Sensor.

Component Testing

Static Test

Measure and record the resistance of the B75B Mass Air Flow/Intake Air Temperature Sensor at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance (IAT) Temperature Versus Resistance (IAT)Temperature Versus Resistance (ECT) Temperature Versus Resistance (ECT) table.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Mass Airflow Sensor Replacement Service and Repair

* Control Module References Control Module References for ECM replacement, programming, and setup