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 | P0113* | P0111 |
Low Reference | -- | P0111, P0113 | P0113* | P0111 |
* 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)* |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)* |
* 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 greater 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 greater 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 greater 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 greater than 2 seconds. |
P0112 and P0113
| • | The engine run time is greater than 3 minutes. |
| • | The engine is idling for greater 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 greater than 132°C (270°F) for greater than 4 seconds or cumulative of 50 seconds.
P0113
The ECM detects that the intake air temperature is less than -42°C (-44°F) and remains steady within 3°C (5°F) during an air flow increase of greater 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 greater 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. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
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 the Freeze Frame/Failure Records. DTCs P0111, P0112, or P0113 should not set.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
- Remove the fuse that supplies B+ to circuit terminal X2-56 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 X2-56 of the ECM.
- Ignition ON, verify that the scan tool IAT sensor parameter is at -40°C (-40°F).
- Ignition ON, install a 3A fused jumper wire between the signal circuit terminal D and the ground circuit terminal C. Verify the scan tool IAT sensor parameter is greater than 134°C (274°F).
- If all circuits test normal, test or replace the MAF/IAT sensor.
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 the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests 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 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 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. |
