Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The PCM applies 5.0V 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 Setting the DTC
| • | No active ECT sensor, MAF sensor or VSS DTC present. |
| • | Vehicle speed is less than 35 mph. |
| • | Engine running for over 3 minutes. |
| • | Mass Air Flow is less than 12 gm/s. |
| • | Engine Coolant Temperature is greater than 60°C (140°F). |
| • | IAT signal voltage indicates an intake air temperature less than -32°C (-25.6°F). |
| • | The above conditions are present for at least 17.5 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 PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Intermittents and Poor Connections Diagnosis Repairing Connector Terminals and Connector Repairs . |
| • | 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 fault. Wiring Repairs . |
If DTC P0113 cannot be duplicated, the information included in the Fail Records data can be useful in determining vehicle mileage since the DTC was last set.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
Verifies that the fault is present.
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If DTC P0113 can be repeated only by duplicating the Fail 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. 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 being replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||
Is Intake Air Temp below the specified value? | -38°C (-36°F) | |||
Does scan tool indicate DTC P0113 failed? | -- | Go to Diagnostic Aids | ||
4 |
Improtant: If the 3 amp fuse blows, locate and repair a short to voltage in the IAT Signal wire. Is Intake Air Temp at the specified value? | 140°C (284°F) | ||
5 |
Is Intake Air Temp at the specified value? | 140°C (284°F) | ||
6 | Check for poor connections at the IAT sensor and replace terminals if necessary. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals and Connector Repairs . Did any terminals require replacement? | -- | ||
7 |
Was the IAT sensor ground circuit open? | -- | ||
8 |
Was the IAT signal circuit open? | -- | ||
9 | Check for a poor sensor ground or IAT signal circuit terminal connection at the PCM and replace terminals if necessary. Refer to Wiring Repairs . Did any of the terminals need to be replaced? | -- | ||
10 | Replace the IAT sensor. Refer to IAT Sensor Replacement . Is the action complete? | -- | -- | |
|
Important: Replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||
12 |
Does scan tool indicate DTC P0113 failed? | -- | System OK |
