Symptoms of bad IAT Sensor in A Truck

The latest trucks come with several sensors we might not know all of and their functions. It is tough to recite all these sensors and their specific roles in your truck. Every function in your truck is supported by a sensor that gives feedback. There is a vehicle Engine Control Module (ECM) that does the role of comprehending messages relayed by the sensors. The ECM does the role of qualifying the number of equations that are vital in supporting the efficient operation of your truck. Here, we will cover the IAT sensor in a truck.

Symptoms of bad IAT Sensor in A Truck

The modern internal combustion engine is a house to several sensors. One of the sensors is the Intake Air Temperature (IAT). Let us go through some basics of IAT sensors and also the symptoms of a bad IAT sensor.

What is an IAT Sensor?

An IAT is a sensor that monitors the temperature of the air getting into the engine’s intake tract. Every cylinder requires air(oxygen) to complete the process of combustion. IAT performs similarly to a thermometer monitoring the air temperature, which gets into every combustion chamber. The IAT does not use mercury to provide accurate temperature, but it gives the ECM/PCM feedback regarding voltage.

The ECM then interprets the voltage presented from the IAT and gives the temperature in terms of readable figures. 

Symptoms of Bad IAT Sensor

There are various symptoms that your truck will show when the intake air temperature is failing. The guide will enlighten you on some signs you will experience when your IAT starts to fall. 

Engine Check Light On the Dashboard

The engine check light symbolizes several issues with the engine. In case your IAT is faulty, the ECM will not be able to interpret some codes from the IAT. The ECM will initiate the engine check light when it cannot store the incorrect code. In such a case, when the engine check light appears, think of IAT as one of the causes.

Rough Idle

Idle is a situation where the engine runs, but the gears are not engaged. The air-to-fuel mixture in the combustion chamber initiates idling. When the IAT malfunctions, the engine cannot determine the accurate air-to-fuel ratio for effective combustion. As a result, you will experience erotic idling.

Difficulty in Starting Your Truck

You will note that your IAT starts to fail when your truck becomes challenging. Your truck might not start because the ECM will take time to determine the correct fuel quantity necessary to mix with the air in the combustion chamber to initiate combustion. 

Engine Misfire

Engine misfire is evidence that your IAT is starting to become faulty. Your truck cannot read the accurate temperature of the air entering the combustion chamber. The ECM will find it difficult to determine the proper amount of fuel to be delivered to the combustion, which leads to engine misfire when you ignite your truck.

Bad Fuel Economy

When your IAT fails, the rate at which your truck will consume fuel will go high—the higher fuel consumption results from the ECM’s inability to specify the intake air temperature values. 


The intake air temperature sensor determines the temperature of air getting into the combustion chamber. If it becomes faulty, the ECM finds reading the codes it receives challenging, leading to some of the above signs. 

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