Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The PCM applies 5 volts through a pull-up resistor to the IAT sensor. When the intake air is cold, the sensor resistance is high and the PCM will monitor a high signal voltage on the IAT signal circuit. If the intake air is warm, the sensor resistance is lower causing the PCM to monitor a lower voltage. DTC P0113 will set when the PCM detects an excessively high signal voltage on the intake air temperature sensor signal circuit.
Conditions for Running the DTC
| • | No active ECT sensor, MAF sensor or VSS DTCs present. |
| • | The engine has been running for over 3 minutes. |
| • | Vehicle speed is less than 8 km/h (5 mph). |
| • | Mass Air Flow is less than 8 gm/s. |
| • | Engine Coolant Temperature is greater than 60°C (140°F). |
Conditions for Setting the DTC
| • | IAT signal indicates an intake air temperature less than -38°C (-37°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 and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been 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 the scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at the PCM. |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, observe the IAT display on the scan tool while moving connectors and wiring harnesses related to the IAT sensor. A change in the IAT display will indicate the location of the malfunction. |
| • | Skewed or mis-scaled IAT Sensor. |
| Refer to Temperature Versus Resistance table. |
If DTC P0113 cannot be duplicated, the information included in the Freeze Frame/Fail Records data can be useful in determining vehicle mileage since the DTC was last set.
Test Description
Number(s) below refer to the Step number(s) on the Diagnostic Chart:
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Verifies that the fault is present
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If DTC P0113 can be repeated only by duplicating the Fail Records conditions, refer to the Temperature Vs. Resistance Values Table. The 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. If the IAT sensor appears to be OK, the fault is intermittent; refer to Diagnostic Aids.
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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 replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Does the scan tool indicate IAT less than the specified value? | -38°C (-37°F) | |||
Does the scan tool indicate this DTC failed this ignition? | -- | Go to Diagnostic Aids | ||
4 |
Does the scan tool indicate IAT more than the specified value? | 135°C (275°F) | ||
5 |
Does the scan tool indicate IAT more than the specified value? | 135°C (275°F) | ||
6 | Test/inspect for a short to voltage or poor connections at the IAT sensor. Refer to Wiring Repairs , Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | ||
7 |
Did you find and correct the condition? | -- | ||
8 |
Did you find and correct the condition? | -- | ||
9 | Inspect for a poor sensor ground circuit or IAT signal circuit connection at the PCM. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | ||
10 | Replace the IAT sensor. Refer to Intake Air Temperature Sensor Replacement Did you complete the replacement? | -- | -- | |
|
Important: Replacement PCM must be programmed. Powertrain Control Module Replacement/Programming Replace the PCM. Did you complete the replacement? | -- | -- | ||
12 |
Does the DTC reset? | -- | System OK |
