Location and Function of the Air Intake Temperature Sensor in Cars

Cars that use an injection system usually have a number of sensors. One of them is the Intake Air Temperature Sensor, often referred to as IATS. This sensor works to detect the temperature of the air entering the car's engine. The installation of the IATS sensor can be integrated with another sensor, namely the Mass Air Flow Sensor, but it can also be separate. 

Understanding the Intake Air Temperature Sensor and Its Location

Changes in the air temperature in the throttle body must be continuously monitored. The component responsible for monitoring this air is called the intake air temperature sensor.

The location of the IATS is in the intake duct, specifically in the air intake channel between the air filter and the throttle body. However, it can also be placed at the back of the air filter. 

Function of the Intake Air Temperature Sensor

What about its function? It is important to know that the IATS is used to detect the air temperature in the intake manifold.

The Intake Air Temperature Sensor can work well because of a component called a thermistor. A thermistor is an electronic component that has a resistance value that varies according to the temperature and air temperature around it. 

There are 2 types of thermistors, the first is the Positive Temperature Coefficient, or PTC.

This thermistor has a high resistance value when the surrounding temperature heats up. The resistance will become low when the surrounding temperature decreases.

The other type is the Negative Temperature Coefficient thermistor, or NTC. This thermistor has an inverse temperature value. Thus, when the surrounding temperature is hot, the resistance will become lower.

In contrast, when the temperature is cold, the resistance actually increases. Generally, the IATS relies on NTC thermistors. This type of thermistor will detect temperature changes in the intake and then compare its values. 

Read Also: Function of the Car Intake Manifold

How the Intake Air Temperature Sensor Works

After understanding the function of the IATS, the next step is to learn how this component works. The IATS will be supplied with voltage or electricity from a source such as a battery.

This voltage is obtained from the ECM or Engine Control Module and is channeled into the thermistor.

Then it is channeled using the THA terminal and is output from the thermistor through E2 in the ECM. The ECM will then supply a voltage of 5 volts to the IAT. 

When the air inside the intake is at a low temperature, the resistance value will change to become higher.

Finally, the output voltage will decrease. This change will be read by the ECM and will be used to determine the amount of fuel entering the engine cylinder. 

If the injector hole is wide open, the amount of fuel injected will increase.

However, if the hole is small, the amount of fuel injected will decrease. 

Signs of IATS Problems

Another important thing you should know is the signs that this component is having problems. Signs of a problematic Intake Air Temperature Sensor include the car engine having difficulty starting.

This is caused by the sensor that should be able to detect the surrounding temperature not functioning. 

This affects the fuel supply in the combustion chamber, causing it to be more restricted. There is no fuel and the combustion chamber is not functioning. Even if the spark plug can work normally, no power is produced.

Another sign is that fuel consumption becomes increasingly wasteful. If you usually need 1 liter of gasoline for 3 days, now 1 liter of gasoline may only last for one day. This excessive fuel consumption is caused by the IATS malfunctioning and unable to detect the air temperature entering the intake. 

If you find signs of the intake air temperature sensor malfunctioning as described above, make sure to take your car for service at a Daihatsu authorized workshop.