What is an IAT Sensor? | What are Symptoms of bad IAT Sensor?

Every car engine is a precisely tuned machine with a number of interconnected systems and parts that operate in unison to provide the best performance. The engine control unit (ECU) of the automobile cannot operate correctly without the sensors. To determine the proper air-fuel combination, the IAT sensor, for instance, detects the temperature of the air entering the engine.

What is IAT Sensor?

The powertrain control module (PCM) receives data from the intake air temperature sensor or IAT sensor, which tracks the temperature of the air entering the engine. 

The appropriate air-fuel mixture ratio is then controlled by the PCM to ensure optimal combustion. 

For optimal mixes and effective engine performance, the car computer will supply less fuel if the IAT sensor detects warm air entering the engine since the air density is lower.

As a result, the engine’s performance will alter significantly if the IAT sensor is damaged.

IAT Sensor Working

In order for the IAT sensor’s tip to detect air flow, auto manufacturers often mount it on top of the intake manifold or in the space between the air filter housing and the intake manifold. The MAP sensor doubles as an intake air temperature sensor on car engines that track air volume using a MAF sensor.

On V-type engines, some manufacturers mount two intake air temperature sensors. On engines with separate or split intake manifolds, this is very typical.

A thermistor is an intake air temperature sensor. This implies that the signal’s sensitivity to temperature variations varies.

It functions similarly to the coolant sensor. The reference or resistance voltage applied by the vehicle computer to the sensor is used to calculate the air temperature from the voltage it gets back from the sensor.

Directly correlated with variations in air temperature is the return voltage. The voltage that returns to the vehicle computer is impacted by variations in sensor resistance.

Air temperature sensors are used in conjunction with automated climate control systems in some automobiles. Some sensors measure the temperature of the outside air as well as the air within the passenger compartment.

Please take notice that the temperature sensor for the climate control systems is located outside the engine compartment, thus engine heat won’t have an impact on the measurement. The climate control air temperature sensor is often mounted behind the grille or in the cowl region.

These air temperature sensors for climate control function similarly to IAT sensors. However, some of them read the inside temperature of the car using infrared sensors.

Bad IAT Sensor Symptoms

1) Poor Fuel Economy 

For best fuel efficiency, the engine control unit continually modifies the air-fuel ratio. The catch is that the engine control unit adjusts the air-fuel mixture by using a number of sensors, including IAT, MAF, and MAP sensors.

Gas mileage will either dramatically increase or decrease if any of these parts fail. Less miles per gallon might indicate that your IAT sensor is subpar.

2) Bad Idling

Engines in moving vehicles should idle as quietly as feasible. A rough idle indicates that one or more parts or modules are broken.

You can have a defective IAT sensor that is producing an incorrect air-fuel mixture ratio.

The intake air temperature sensor is broken if the engine makes brief hiccups while idling. Many problems, including the check engine light, might result in harsh idling.

3) Illuminated Check Engine Light

The vehicle’s computer keeps track of every system activity. The check engine light on the dashboard will come on if any sensor or system is malfunctioning. Any underlying problems in the system will be signaled to the driver via the engine warning light.

The instrument cluster’s warning light will also turn on if the IAT sensor malfunctions. To find out what’s issues with the system, you should thus use an OBD2 scanner to diagnose the car anytime these light shines on the instrument cluster.

4) Misfiring 

When the combustion process inside the engine cylinder fails, misfires happen. The incorrect air-fuel combination or a bad spark might both be to blame for this.

Misfires can be felt as hitches or pauses when accelerating. If you see this during acceleration, your IAT sensor could be malfunctioning.

5) Poor Engine Performance 

The PCM may believe that the air in the engine is colder or warmer than it actually is as a result of a malfunctioning intake temperature sensor. The PCM may compute the air and fuel mixture incorrectly as a result of an erroneous signal, which would reduce acceleration.

The engine control module is configured to determine how much extra gasoline is needed when the temperature drops.

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