Circuit Description
The intake air temperature (IAT) sensor is a thermistor that controls signal voltage to the PCM. When the air is cold, the sensor resistance is high, therefore the PCM will see a high signal voltage. As air warms, the sensor resistance becomes less and the voltage drops.
Conditions for Running the DTC
The engine has been operating for 8 minutes.
Conditions for Setting the DTC
| • | The IAT is less than or equal to -40°C (-40°F). |
| • | All diagnosticc set conditions met for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive drive trip the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the Failure Records store this information. If the diagnostic reports a failure on the second consecutive drive trip, the Freeze Frame records the operating conditions at the time of failure and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without a fault condition. |
| • | A History DTC will clear after forty consecutive warm-up cycles, if this or any other emmision related diagnostic does not report any failures. |
| • | Use of a scan tool will clear the DTC codes. |
Diagnostic Aids
The scan tool displays intake air temperature in degrees centigrade. Refer to Symptoms . A skewed sensor could result in poor driveability complaints. Refer to Temperature Versus Resistance .
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
This step determines if DTC P0113 is a hard failure or an intermittent condition.
-
This step will determine if there is a wiring problem or a malfunctioning PCM.
-
This step determines if there is a short to voltage on the signal circuit. A short to voltage increases current flow through the sensor which overwhelms the sensor. This doesn't allow the sensor to pull down the circuit to the correct voltage and thus display the correct temperature.
-
After repairing the short to voltage, check the sensor for proper operation.
Step
| Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool Capture Info to save freeze frame and failure records for reference. The control module's data is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the IAT display a temperature colder than or equal to the specified value? | -30°C (-22°F) | |||
Does the scan tool display an IAT temperature greater than or equal to the specified value? | 151°C (303°F) | |||
4 | Jumper the IAT sensor signal circuit to a known good ground. Does the scan tool display an IAT temperature greater than or equal to the specified value? | 151°C (303°F) | ||
5 | The DTC is intermittent. If no other DTCs are stored, refer to Diagnostic Aids. Are than any other DTCs stored? | -- | Go to the Applicable DTC Table | Go to Diagnostic Aids |
6 |
Did you find a problem? | -- | ||
7 |
Did you find a problem? | -- | ||
8 |
Did you find a problem? | -- | ||
With a J 39200 DMM set to the mA scale, measure the current at the IAT harness connector terminals. Is the current less than the specified value? | 50 mA | |||
Repair the short to voltage on the IAT signal circuit. Is the action complete? | -- | -- | ||
11 | Inspect the PCM connectors for proper connections and replace the terminals, if necessary. Refer to Wiring Repairs . Did you find a problem? | -- | ||
12 | Replace the IAT sensor. Refer to Intake Air Temperature Sensor Replacement Is the action complete? | -- | -- | |
13 | Replace the PCM. Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming Is the action complete? | -- | -- | |
14 |
Does the scan tool indicate the diagnostic Passed? | -- | ||
15 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the Applicable DTC Table | System OK |
