Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptor
DTC P0111: Intake Air Temperature (IAT) Sensor Circuit PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IAT Sensor Signal | P0112 | P0113, P0114 | P0113¹, P0114 | P0111 |
Low Reference | -- | P0113, P0114 | P0113², P0114 | P0111 |
¹ Sensor damage may occur if the circuit is shorted to B+. ² Internal ECM damage may occur if the circuit is shorted to B+. | ||||
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: Varies with ambient air temperature and engine operation. | |||
IAT Sensor Signal | 128°C (248°F) | -40°C (-40°F) | -40°C (-40°F)¹ |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)¹ |
¹ Internal ECM or sensor damage may occur if the circuit is shorted to B+. | |||
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:
Temperature | IAT Resistance | IAT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
Condition 1
| • | The engine coolant temperature (ECT) and intake air temperature (IAT) are within 3°C (6°F) of each other at startup. |
| • | The ECT has decreased greater than 45°C (81°F) from the previous ignition cycle. |
| • | The IAT is between -10 and +85°C (+13 and +186°F). |
| • | The ECT is greater than -10°C (+13°F). |
| • | The engine run time is greater than 700 seconds. |
| • | The vehicle has been driven greater than 7 km (4 miles) |
| • | DTC P0111 runs continuously once the above conditions are met for greater than 2 seconds. |
Condition 2
| • | The ECT is greater than -10°C (+13°F). |
| • | The MAF is greater than 4 g/s. |
| • | DTC P0111 runs continuously once the above conditions are met for greater than 2 seconds. |
Condition 3
| • | The ECT is greater than -10°C (+13°F). |
| • | The MAF is greater than 7 g/s. |
| • | DTC P0111 runs continuously once the above conditions are met for greater than 2 seconds. |
Conditions for Setting the DTC
Condition 1
| • | The ECM detects that the IAT does not change greater than 3°C (6°F). |
| • | The condition exists for greater than 2 seconds. |
Condition 2
| • | The ECM detects that the IAT increased less than 3°C (6°F) or greater than 45°C (81°F). |
| • | The condition exists for greater than 2 seconds. |
Condition 3
| • | The ECM detects that the IAT increased less than 3°C (6°F) or greater than 35°C (63°F). |
| • | The condition exists for greater than 2 seconds. |
Action Taken When the DTC Sets
DTC P0111 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0111 is a Type B DTC.
Diagnostic Aids
If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (6°F).
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- Verify that DTCs P0112 or P0113 are not set.
- Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
| ⇒ | If DTCs P0112 or P0113 are set, refer to DTC P0112 or P0113 . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the IAT sensor.
- Ignition ON, verify the scan tool IAT sensor parameter is at -40°C (-40°F).
- Install a 3A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool IAT sensor parameter is greater than 125°C (240°F).
- If all circuits test normal, test or replace the IAT sensor.
| ⇒ | If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | 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 ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the IAT sensor.
- Test the sensor by varying the sensor temperature while monitoring the sensor resistance. .
- Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5 percent of the specification
Important: A thermometer can be used to test the sensor off the vehicle.
| ⇒ | If not within the specified range, replace the IAT sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
