Diagnostic Trouble Code (DTC) P0113

Intake Air Temperature Sensor High Voltage

 

 

What is the circuit like?

 

  • In order to regulate the signal voltage going to the engine control module (ECM)  the Intake Air Temperature (IAT) Sensor utilizes the thermistor.
  • This circuit receives a 5 volt reference voltage and a ground to the sensor supplied by the ECM.
  •  The IAT sensor signal voltage will be high when the air is moderately cold as the resistance will be high.
  • The IAT sensor signal voltage will be low when the air is moderately warm as the resistance will be low.

 

 

QUESTION- WHEN DOES THE DTC SET?

ANSWER- When IAT voltage is < 4.99V

 

Measures Taken When DTC Sets

When Does DTC Clear?

1)   After three successive trips with a fail the Malfunction Indicator Lamp (MIL) will be seen glowing.

 

1)   The MIL will automatically switch off after four successive ignition cycles in which the diagnostic will run flawlessly

2)  The operating conditions recorded by the ECM at the time the diagnostic failed, will be stored in the Freeze Frame and Failure Records will buffer

2)   A history DTC will be unset after 40 repetitive warm up cycles without a fault

3)   A history DTC is stored.

3) The scan tool will unset all DTCs

4)   The ECM will default to 605C (1405F) for intake air temperature

4)  De-linking the ECM battery feed for 10 seconds              

5)   The scan tool will not show the defaulted value

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Diagnostic Assistance:

  • IAT sensor must be compared to the engine coolant temperature (ECT) sensor if the vehicle is at ambient temperature.
  • The IAT sensor and the ECT sensor must be near similar, desirably.
  • For the ease of estimating an existing skewed sensor, the Temperature vs.  Resistance Values table should be referred to.