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 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
| • | DTCs P0117, P0118, P0125, P0128, P0502, P0503, P1114, or P1115, are not set. |
| • | The engine has been running for over 3 minutes. |
| • | The vehicle speed is less than 5 mph (8 kph). |
| • | The mass air flow is less than 8 g/s. |
| • | The engine coolant temperature is more than 60°C (140°F). |
Conditions for Setting the DTC
| • | IAT signal voltage indicates an intake air temperature less than -38°C (-37°F). |
| • | The above conditions are present for at least 110 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connections at PCM--Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. If DTC P0113 cannot be duplicated, the information included in the Failure Records data can be useful in determining vehicle mileage since the DTC was last set. |
| • | A 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. |
| • | A skewed or mis-scaled IAT sensor--Refer to Temperature Versus Resistance . |
| • | If a short to a seperate 5-volt source occurs, this DTC may set. If this is found to be a problem, a continuity test to all other PCM circuits will be necessary in order to diagnose the specific circuit. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Verifies that the malfunction is present.
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If DTC P0113 can be repeated only by duplicating the Failure Records conditions. 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 malfunction 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 |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Is intake air temperature less than the specified value? | -38°C (-37°F) | Go to Step 4 | Go to Step 3 | |
Does the scan tool indicate DTC P0113 failed? | -- | Go to Step 4 | Go to Diagnostic Aids | |
4 |
Important: If the 3 amp fuse blows, locate and repair the short to voltage in the sensor signal wire. Is intake air temperature more than the specified value? | 135°C (275°F) | Go to Step 6 | Go to Step 5 |
5 |
Important: If the 3 amp fuse blows, locate and repair the short to voltage in the sensor signal wire. Is intake air temperature more than the specified value? | 135°C (275°F) | Go to Step 7 | Go to Step 8 |
6 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 |
7 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
8 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
9 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
11 | Replace the IAT sensor. Refer to Intake Air Temperature Sensor Replacement Is action complete? | -- | Go to Step 13 | -- |
Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- | |
13 |
Does the DTC run and pass? | -- | Go to Step 2 | Go to Step 2 |
14 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
