5 Signs of a Faulty Intake Air Temperature Sensor


The intake air temperature sensor plays a role, in the engine management system of a vehicle. Its main function is to measure the temperature of the air entering the engine and relay this information to the engine control unit (ECU). This data is crucial for the ECU to determine and maintain an air fuel mixture for combustion resulting in optimal engine performance and effective control, over emissions.

car engine

Your vehicles engine depends on a variety of sensors to operate at its best and one important sensor is the Intake Air Temperature (IAT) sensor. This component plays a role, in ensuring that your engine receives the amount of oxygen for efficient combustion. However like any sensor the IAT sensor can develop issues over time which can negatively impact engine performance. In this article we will explore the indications of an IAT sensor discuss how it works and where it is located well as provide information about the cost of replacing it. So if you’ve noticed a decrease in acceleration or an illuminated check engine light that won’t go away keep reading to discover more, about the symptoms and potential solutions related to an IAT sensor.

Signs of a Faulty Intake Air Temperature Sensor

One of the signs that your cars IAT sensor is not functioning properly is the illumination of the check engine light, on your dashboard. Nonetheless there are indicators that might suggest a problematic IAT sensor. Now let’s explore each of these signals in depth.

1. Hard Cold Start

Starting your car on a morning can be quite the challenge especially if theres an issue, with the IAT sensor. The IAT sensor plays a role, in providing temperature information to the engine control module (ECM) regarding the air coming into the engine. When this sensor malfunctions it can send temperature readings to the ECM causing fuel injection problems. As a result you may experience difficulties in igniting the engine and achieving an idle.

2. Drop in Acceleration

If the IAT sensor is faulty it can cause a decrease, in engine acceleration especially when you suddenly accelerate. The sensors main job is to measure the temperature of the air coming into the engine. This information helps the ECM (engine control module) figure out how fuel to mix with the air, for combustion. If the IAT sensor gives readings the ECM might make a mistake in calculating the right fuel mixture, which can lead to either little or too much fuel. As a result you will experience reduced acceleration and overall engine performance.

3. Rough Idle

One indication of an IAT sensor is experiencing an idle. When the engine is idling it depends on control of the air fuel mixture to maintain a RPM. If the IAT sensor is not functioning properly it might send temperature readings to the ECM leading to an imbalance, in the air fuel mixture. Consequently this can cause an idle marked by RPM fluctuations and the possibility of stalling.

4. EGR Valve Dysfunction

In cars the Engine Control Module (ECM) utilizes the intake air temperature to control how the Exhaust Gas Recirculation (EGR) valve functions. When the Intake Air Temperature (IAT) sensor malfunctions it can negatively affect the performance of the EGR valve. This can result in problems, like decreased fuel efficiency and higher emissions. If you observe a decrease in fuel economy along with signs it’s crucial to consider the impact of a faulty IAT sensor, on the EGR valve.

5. Poor Fuel Economy

The Engine Control Module (ECM) continuously adapts the air fuel mixture to enhance fuel efficiency using data, from the Intake Air Temperature (IAT) sensor. Nonetheless in case the IAT sensor provides temperature readings the ECM might incorrectly calculate the fuel needs resulting in reduced fuel economy. If you observe a decline, in your vehicles fuel efficiency without any reasons it is possible that a defective IAT sensor is causing the issue.

What is an Intake Air Temperature Sensor?

The IAT sensor plays a role, in the engine management system of your vehicle. Its main function is to measure the temperature of the air entering the engine and relay this information to the ECM. With this data the ECM can make adjustments to optimize engine performance and fuel efficiency by regulating the air fuel mixture and ignition timing.

Where is the IAT Sensor Located?

The exact placement of the IAT sensor may differ based on the make and model of your car. Generally you’ll find the IAT sensor either in the manifold or combined with the Mass Air Flow (MAF) sensor. The intake manifold is usually positioned between the air filter and intake valves making it a suitable spot, for gauging air temperature. To pinpoint the location of the IAT sensor in your vehicle consult the manufacturer’s service manual.

Diagnosis of the Intake Air Temperature Sensor

Diagnosing a malfunctioning IAT sensor can be quite simple. Follow these steps to figure out whether the IAT sensor is causing problems, with your vehicle;

  1. Connect an OBD2 scanner to your vehicle’s diagnostic port and turn on the engine.
  2. Use the scanner to retrieve any trouble codes related to the IAT sensor.
  3. Check the live data stream on the scanner and compare the temperature readings from the IAT sensor to the ambient temperature.
  4. If the readings are significantly off or unrealistic, it indicates a potential problem with the IAT sensor.
  5. To confirm the diagnosis effectively you can conduct an ohm measurement, on the IAT sensor. Compare it to the specifications mentioned in the repair manual.
  6. If the readings are outside the acceptable range, it’s likely that the IAT sensor needs to be replaced.

Replacement Cost of the Intake Air Temperature Sensor

The cost of replacing an IAT sensor can vary based on factors, such, as the type and model of your car well as the labor charges in your area. On average you can expect an IAT sensor to cost between $20 and $150. However if the IAT sensor is combined with the MAF sensor the cost can go up significantly reaching $400 for some MAF sensors. The labor charges for replacing the IAT sensor usually range from $20 to $100. To obtain an estimate, for your vehicle it’s advisable to consult a mechanic or visit a dealership.


A defective Intake Air Temperature (IAT) sensor can have an impact, on how your vehicles engine performs and how efficiently it uses fuel. It’s important to be able to recognize the signs of an IAT sensor, such as problems with the engines performance and the check engine light coming on. This will help you diagnose and fix the issue promptly. If you suspect that your IAT sensor isn’t working properly it’s best to seek advice, from a mechanic or go to a dealership so they can accurately identify the problem and replace the sensor if needed. By ensuring that your IAT sensor is functioning correctly you’ll be able to maintain engine performance and extend the life of your vehicle.

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