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 provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0111: Intake Air Temperature (IAT) Sensor Circuit PerformanceDTC P0112: Intake Air Temperature (IAT) Sensor Circuit Low Voltage
DTC P0113: Intake Air Temperature (IAT) Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IAT Sensor Signal | P0112 | P0111, P0113 | P0113¹ | P0111 |
Low Reference | -- | P0111, P0113 | P0113¹ | P0111 |
¹ Internal ECM or sensor 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: -39° to +134°C (-38° to +274°F) Varies with ambient temperature. | |||
IAT Sensor Signal | 135°C (275°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 an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the intake air. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
P0111 Idle Test
| • | Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass. |
| • | DTCs P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set. |
| • | The engine coolant temperature (ECT) at engine start is less than 85°C (185°F). |
| • | The ECT is more than 66°C (151°F). |
| • | The vehicle speed is less than 10 km/h (6 mph). |
| • | DTC P0111 runs continuously once the above conditions are met for more than 2 seconds. |
P0111 Cruise Test
| • | Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass. |
| • | DTCs P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set. |
| • | The ECT at engine start is less than 85°C (185°F). |
| • | The vehicle speed is more than 40 km/h (25 mph). |
| • | The MAF is between 11-42 g/s. |
| • | Decel fuel cut-off (DFCO) is not active. |
| • | DTC P0111 runs continuously once the above conditions are met for more than 2 seconds. |
P0112 and P0113
| • | The engine run time is more than 3 minutes. |
| • | The engine is idling for more than 10 seconds. |
| • | The DTCs runs continuously once the above conditions are met. |
Conditions for Setting the DTC
P0111
The ECM detects that the IAT remains steady within 2°C (4°F) during the idle test. The condition exists for a total of 16 seconds. Or, the ECM detects that the IAT decreased less than 2°C (4°F) during the cruise test. The condition exists for a total of 28 seconds.
P0112
The ECM detects that the intake air temperature is more than 132°C (270°F) for more than 4 seconds or cumulative of 50 seconds.
P0113
The ECM detects that the intake air temperature is less than -42°C (-43.6°F) and remains steady within 3°C (5°F) during an air flow increase of more than 999 grams. The scan tool is limited to -40°C (-40°F), so the diagnostic procedure uses -39°C (-38°F) to determine if there is an IAT condition. The condition exists for more than 4 seconds or cumulative of 50 seconds.
Action Taken When the DTC Sets
DTCs P0111, P0112, and P0113 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0111, P0112, and P0113 are Type B DTCs.
Diagnostic Aids
| • | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
| • | High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit could set a DTC. |
| • | Use the J 35616 Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Special Tools Required
J 35616 Connector Test Adapter Kit
Circuit/System Verification
Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. DTC P0111, P0112, or P0113 should not set.
Circuit/System Testing
- Ignition OFF, disconnect the MAF/IAT sensor.
- Ignition ON, verify that the IAT sensor parameter is at -40°C (-40°F).
- Ignition OFF, remove the fuse that supplies B+ to circuit terminal C2-56 of the ECM.
- Test for less than 5 ohms between the low reference circuit terminal E and ground.
- Install the fuse that supplies B+ to circuit terminal C2-56 of the ECM.
- Ignition ON, install a 3A fused jumper wire between the signal circuit terminal D and ground circuit terminal C. Verify the IAT sensor parameter is greater than 134°C (274°F).
- If all circuits/connections test normal, test or replace the MAF/IAT sensor.
| ⇒ | If greater than -40°C (-40°F), test the signal circuit for a short to ground. If the circuit/connections test normal, replace the engine control module (ECM). |
Notice: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
| ⇒ | If greater than 5 ohms, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM. |
Important: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
| ⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector of the IAT sensor.
- 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 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 the Resistance vs Temperature is not within 5 percent, 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 |
