What is Inlet Air Temperature? Information about Sensors

What is Inlet Air Temperature Sensor

Inlet air temperature is a very important performance characteristic in automotive engines in general. Because of this, most people are asking about what is inlet air temperature sensor. So, it is very important stuff to know about.

What is Inlet Air Temperature?

It means the temperature of the inlet air to the intake manifold. And there is an inlet air temperature sensor that sends the temperature of this inlet air to the ECU system of the car. This is very important information that the system adjusts the ideal air-fuel mixture for the car.

There is special software in a car that defines the optimum air-fuel mixture for changing atmospheric conditions. This software makes the car run very efficiently way in different air conditions. The Inlet air temperature sensor is very important here.

The sensor sends the temperature of the intake air to the software. And in each temperature, the density of the atmospheric air changes. Because of this change, the required amount of fuel to burn inside the cylinders changes. And the software system sends a specific amount of fuel to the injectors that will best for burning the air that comes inside the intake manifold. So, the vehicle will efficiently work in this case.

For example, on hot days the density of the atmospheric air is thinner than the cold air. Because of it, the ECU system will send higher fuel to the combustion chambers because of the higher amount of oxygen in cold air. And in hot air temperatures, the ECU system will send less amount of fuel because the air is thinner. But if the system sends the same amount of fuel to the system, there will be excess unburnt fuel will go through the exhaust pipe. And this will lead to efficiency problems.

The Difference between Carburetors and Injection Systems

In the old ignition engines, there were carburetors and the valves of these carburetors. If the driver pushes the gas pedal, the valve of the carburetor opens and a much higher amount of air-fuel mixture comes into the engine.

But in carburetor systems, there are no kinds of calculations o the air-fuel mixture. The air-fuel mixture is generally the same for all conditions. So with the changing temperatures, there can be inefficient fuel consumption take place.

But in modern cars, there are fuel injection systems and lots of sensors such as inlet air temperature sensors make fuel consumption much more efficient.

Also in general, electronic systems are much more hşgher in price if we compare them with mechanical systems such as carburetors. But in terms of fuel consumption efficiency, the ROI will be very good with the electric injection systems.

Also, there are different kinds of emission regulations for cars in different regions of the world. With the carburetor systems, most cars can not ensure these emission standards in general.

How Much Does It Cost To Change the Inlet Air Temperature Sensor?

If you have a problem with this sensor, the algorithm can not make any calculations about which amount of air it needs to send to the engine system. So, you will have problems while you are running your car. Maybe there are additional algorithms in the ECU system that the car to work without any inlet air temperature sensor. But you will have the signal from the car to check the sensor. For example, check this sensor available on

HiSport Intake Air Temperature Sensor

HiSport Intake Air Temperature Sensor

  • Compatible with Chrysler Dodge Avenger Challenger Charger Durango Grand Caravan Journey Jeep RAM
  • High precision.
  • Compatible with OEM specifications.

If you check the temperature sensor example above from Amazon, they are generally compatible with different kinds of car brands in general. And they are manufacturing these aftermarket sensors according to the OEM specifications. But if you want to be sure about the efficiency of your car, you can directly look for the OEM parts from the car service of your car. But in general, OEM parts are much higher in price.

In general, if we look at the aftermarket inlet air temperature sensors, they change between $15-50 according to the brand of your car. And also, you need to pay for the labor. The labor also changes around $50-100. Because they need to rip off the injection system and intake manifold to replace the inlet air temperature sensor.

So, you need to pay around $100 for a full change of the sensors. In general, they are very basic systems.

What Causes Inlet Air Temperature Sensor Failure?

The most common reason for their failure is the contamination that takes place in their sensing mechanism. There is a constant airflow over these sensors. During the time, lots of air come and go through the air temperature sensor and makes it contaminated. So, you need to examine if it works after cleaning. If it does not work, you can change the new one.


As you see above, these sensors are a very important part o automotive engines. And inlet air temperature is a very important parameter for the efficient working of the different kinds of modern cars.

If you have additional questions about the inlet air temperature and the sensors, leave them in the comments section below.

Uğur Uygun

Hello everyone, I am Uğur. I am a mechanical engineer who has experience in different R&D departments of HVAC companies. With my best friend, I decided to build this website to share out knowledge and experience. And also, I am interested in automotive. So, I am writing about automotive and automotive-related articles here. Sharing my knowledge and experiences on these topics is a very big pleasure for me. I am willing to answer all of the questions people have about these topics.

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