Circuit Description
The Intake air temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The Powertrain Control Module (PCM) applies 5.0 volts through a pull-up resistor. When the intake air is cold, the sensor resistance is high, and the PCM will monitor a high signal voltage on the IAT sensor signal circuit. As the intake air warm, the sensor resistance becomes lower, causing the PCM to monitor a lower voltage. If the PCM detects an excessively high IAT sensor signal voltage, a low temperature is indicated, and DTC P0113 will set.
Conditions for Running The DTC
| • | No active ECT, MAF or VSS diagnostic trouble codes (DTCs) are present. |
| • | The vehicle speed is less than 35 mph. |
| • | The mass air flow is less than 12 gm/s. |
| • | The engine coolant temperature is more than 60°C (140°F). |
| • | The engine run time is more than 3 minutes. |
Conditions for Setting the DTC
| • | The IAT signal voltage indicates an intake air temperature that is less than -37°C (-35°F). |
| • | The above conditions are present for at least 20 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Verifies that the fault is present.
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If DTC P0113 can be repeated only by duplicating the Failure Records conditions. The Temperature vs Resistance table may be used to test the IAT sensor at various temperatures to evaluate the possibility of a shifted sensor that may be open above or below a certain temperature. If this is the case, replace the IAT sensor. Refer to IAT Sensor Replacement. If the IAT sensor appears to be OK, the fault is intermittent. Refer to Diagnostic Aids.
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Use a fused jumper during this test. If the IAT signal circuit is shorted to battery or ignition positive voltage the fuse in the jumper will open, indicating a short in the signal circuit.
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This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read only memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the scan tool indicate the IAT parameter is less than the specified value? | -37°C (-35°F) | |||
Does the scan tool indicate that DTC P0113 failed this ignition? | -- | Go to Diagnostic Aids | ||
4 |
Does the scan tool indicate that the IAT parameter is more than the specified value? | 135°C (275°F) | ||
Does the scan tool indicate the IAT parameter is more than the specified value? | 135°C (275°F) | |||
6 | Test the signal circuit of the IAT sensor for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 | Test the ground circuit of the IAT sensor for a high resistance or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 | Test the signal circuit of the IAT sensor for an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
9 | Inspect for faulty IAT sensor ground or signal circuit connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
10 | Inspect for a faulty connections at the IAT sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
11 | Replace the IAT Sensor. Refer to Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | -- | |
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Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | ||
13 |
Does the DTC reset? | -- | System OK |
