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 P0112: Intake Air Temperature (IAT) Sensor Circuit Low VoltageDTC P0113: Intake Air Temperature (IAT) Sensor Circuit High Voltage
DTC P0114: Intake Air Temperature (IAT) Sensor Circuit Intermittent
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
IAT Sensor Signal | P0112, P0114 | P0113, P0114 | P0113, P0114 | P0113, P0114 | P0114, P2199 |
Low Reference | -- | P0113, P0114 | P0113, P0114 | P0113, P0114 | P0114, P2199 |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: -39 to +120°C (-38 to +248°F) | |||
IAT Sensor Signal | 143°C (289°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
Circuit/System Description
The intake air temperature (IAT) sensor is integrated with the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the air when it first enters the induction system. The engine control module (ECM) supplies 5 volts to the IAT sensor signal circuit and supplies a ground to the low reference circuit.
Conditions for Running the DTC
P0112
| • | The ignition is ON or the engine is running. |
| • | This DTC runs continuously within the enabling conditions. |
P0113
| • | The engine is running. |
| • | This DTC runs continuously within the enabling conditions. |
P0114
| • | The ignition is ON or the engine is running. |
| • | This DTC runs continuously within the enabling conditions. |
Conditions for Setting the DTC
P0112
The ECM detects that the IAT is greater than 142°C (288°F) for greater than 15 seconds at idle.
P0113
The ECM detects that the IAT is less than -39°C (-38°F) for greater than 15 seconds at idle.
P0114
The ECM detects that the IAT sensor signal is intermittent or has abruptly changed for greater than 4 seconds.
Action Taken When the DTC Sets
DTCs P0112, P0113, P0114 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0112, P0113, P0114 are Type B DTCs.
Diagnostic Aids
| • | If the engine is cold, then at ignition ON, a properly functioning IAT sensor will gradually increase the scan tool IAT Sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements. |
| • | Depending on the ambient temperature, an IAT sensor signal circuit that is shorted to the MAF sensor signal circuit can cause a DTC P0113 and/or a DTC P0114 to set. This condition may cause either a rapid fluctuation in the IAT Sensor parameter or cause it to become stuck at a given value. |
| • | An IAT low reference circuit that is open can cause the IAT Sensor parameter response to be sluggish. This condition may not necessarily set a DTC. |
| • | A MAF sensor ground circuit that is open will cause a DTC P0113 and/or a DTC P0114 to set. |
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
| Important: Determine the ambient temperature by using an accurate thermometer. |
| • | If the ignition has been OFF for 8 hours or greater, the IAT, the IAT 2 and the engine coolant temperature (ECT) should be within 9°C (16°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool IAT Sensor, IAT 2 Sensor and the ECT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the condition is current. |
| • | Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions. |
Circuit/System Testing
- Ignition OFF, disconnect the MAF/IAT harness connector at the MAF/IAT sensor.
- Ignition OFF, test for less than 5 ohms of resistance between the MAF sensor ground circuit and ground.
- Ignition OFF, test for less than 5 ohms of resistance between the IAT low reference circuit and ground.
- Ignition ON, verify the scan tool IAT Sensor parameter is less than -39°C (-38°F).
- Install a 3A fused jumper wire between the signal circuit and a good ground. Verify the scan tool IAT Sensor parameter is greater than 142°C (288°F).
- If the circuits test normal, test the IAT sensor.
| ⇒ | If greater than the specified range, test the MAF sensor ground circuit for an open/high resistance. |
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. 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. |
| ⇒ | 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
Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance .
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
