Intake Air Temperature Sensor (IAT)

Know all about the IAT

What is it ?

The function of an IAT sensor is to measure the temperature of the air coming into the engine--once it has been mixed with fuel in the carburetor--and direct its flow into the cylinders by opening or closing a flap.
For car engines that are equipped with a carburetor, the Intake Air Temperature (IAT) sensor is an integral part of the vehicle's fuel exhaust system.

Prevent your engine problems,


Maintains your engine in good condition.

Preventive engine cleaning enables you to restore engine parts rather than replacing them, thereby saving vehicle owners on costly parts, such as a new turbocharger (1.350€ - 3.100€), catalytic converter (600€ - 2.000€), DPF (600€ - 2.000€) or EGR valve (370€ - 500€).

These problems result mainly from poor combustion, which stifles the engine.

So before replacing your engine parts, try Carbon Cleaning. A dirty engine as the result of carbon deposits is the new threat to vehicle performance.

Make your online diagnosis
What are the symptoms of a bad IAT Sensor ?

The most obvious symptom will be the check engine light (CEL) lit nice and bright on your instrument cluster. The second will be an IAT sensor malfunction diagnostic trouble code (DTC) stored in the PCM memory.
Here are some of the specific symptoms you'll see/have:
1.   Diagnostic Trouble Codes:
          - P0112: Intake Air Temperature (IAT) Sensor Circuit Low Voltage. This means that the IAT sensor is reporting a temperature of 300 °F (149 °C).
          - P0113: Intake Air Temperature (IAT) Sensor Circuit High Voltage. This means that the IAT sensor is reporting a temperature of -38 °F (-39 °C).
2.   BAD gas mileage.
3.   Black smoke coming out of the tailpipe.
4.   Won't pass the emissions test.
How test the IAT sensor ?

·      Testing for a faulty IAT sensor is not very difficult, and requires only a scanning tool, a multi-meter, and a wire-piercing probe. This process is inexpensive, and is always a good idea before going in for a replacement. To use the scan tool, you need to perform the following steps.

·      Attach the scan tool to the vehicle, and turn on the engine.

·      After turning it on, check for the temperature of the IAT sensor. It should be 10°F above or below the ambient temperature of the vehicle. If this is not the case, you may have a problem with the sensor.

·     Shake the IAT sensor connection to the mass airflow sensor, and check to see if there is any difference in reading. A change in the reading indicates a bad connector, which then has to be replaced.

·      If the temperature reading displays -30 to -40°F, the dashboard light should show the code P0113, and if the reading displays 300°F, the dashboard should show the code P0112.

·      If the reading shows a temperature of 300°F, you need to check if the MAF sensor wires are shorted because of the internal copper getting exposed to each other. Remove all electrical tape to examine the wires and check for signs of damage.

·      Separate the shorted wires and check if the readings turn normal; if not the connector needs to be replaced.

·      Disconnecting the IAT from the MAF should get the temperature reading back to -30 to -40°F. However, if this does not happen, it means that there could be a problem with the vehicle's internal computer, which needs to be checked and solved by a technician.

·      Connecting the 2 IAT wires with jumper cables should change the temperature to 300 °F. If this does not happen, it might mean that the wiring or the computer is bad.

·      Now, to test the IAT sensor with a multi-meter, you should measure the resistance of the sensor. If the multi-meter shows a reading of 0 to 47 Ohms, then you have a problem with the sensor.
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