Have you noticed your car’s engine drop in acceleration lately?
The chances are that your car’s intake air temperature sensor (IAT) is damaged and that it should be fixed immediately to avoid any serious damage to the engine.
In this article, you will learn the symptoms and the meanings of a bad intake air temperature sensor. Let’s begin with the symptoms.
7 Symptoms of a Bad Air Intake Temperature Sensor
- Check Engine Light
- Slow acceleration
- Hard Cold start condition
- Rough idle
- EGR valve affected
- Poor fuel economy
When the IAT sensor fails or gets damaged, it may show some symptoms through which the driver can easily conclude that the problem is with a specific component.
Here is a more detailed list of the 7 most common symptoms of a bad intake air temperature sensor.
Check Engine Light
The first thing you may notice with a bad intake temperature sensor is a check engine light on your dashboard. The engine control unit heavily monitors all sensors in a car engine, and if one fails, it will light up the check engine light immediately.
If you notice a check engine light on your dashboard, check the trouble codes with an OBD2 scanner or let your mechanic do it.
Drop in Acceleration
Due to a faulty intake temperature sensor, the engine control module may think that the engine’s air is colder or warmer than it actually is. A false signal may cause the PCM to miscalculate the air and fuel mixture, resulting in a drop in acceleration.
Colder temperatures require more fuel, which the engine control module is programmed to calculate.
Hard Cold Start Condition
The starting condition is a very critical moment for your car. Your car needs a lot of and the correct amount of fuel.
If your intake temperature sensor makes the engine control unit inject the wrong amount of fuel, you might find it a tough time trying to start your car.
Idle is also one of these conditions when the engine is susceptible to the right air-fuel mixture. This is also a condition when you can feel the faulty air intake temperature sensor’s slightly faulty air-fuel mixture.
If you experience some small hiccups on idle, it can be a faulty IAT sensor.
Misfires occur when the combustion inside the engine cylinder fails. This can be caused by either a faulty spark or a wrong air-fuel mixture.
You can feel misfires as hiccups or interruptions while you accelerate. If you can feel this on acceleration, there may be a problem with your IAT sensor.
EGR Valve Affected
In some cars, the engine control unit uses air temperature to control the EGR valve operation. Due to a faulty IAT sensor, the function of the EGR valve can be affected too.
An EGR valve that does not function properly can cause a lot of strange symptoms in your car.
Poor Fuel Economy
In normal conditions, the engine computer constantly adjusts the fuel and air level mixture to ensure maximum fuel efficiency.
The engine control unit relies on the IAT sensor’s information, and if a false signal is sent, the fuel efficiency decreases or increases significantly.
If you notice a different fuel consumption than normal, it can be because of a failed IAT sensor.
What is an Intake Air Temperature Sensor?
The intake air temperature sensor or IAT sensor has the core function of monitoring the air temperature entering the engine of your vehicle.
This information is beneficial for the engine control unit or ECU for many functions and calculations, such as calculating the air density for effective ignition timing and fuel efficiency.
The computer system of your engine or the PCM requires this information to stabilize and regulate the combustion engine’s air-fuel ratio. It ensures optimum combustion and efficient fuel consumption.
Where Is the IAT Sensor Located?
Often, it is also installed on the intake manifold.
The intake air temperature sensor’s location is not standard due to different locations in a variety of designs. The best way to locate the IAT sensor in your vehicle is to refer to the service manual provided by your manufacturer.
Intake Temperature Sensor Diagnostics
The diagnostic procedure of checking if the IAT sensor has failed is relatively easy. You can do it yourself if you have some basic knowledge and the tools available to you. Have a repair manual for your car ready.
- Connect the OBD2 scanner to your car. Turn on the engine.
- Check the live data and check the temperature of the IAT sensor. Typically, the temperature readings should be 10 degrees more or less than the vehicle’s ambient temperature, depending on the outside temperature and the engine’s temperature.
- If the readings are not realistic, there could be a problem with your IAT sensor or the wirings to it. If the temperature is over 300 degrees or has a low unrealistic value, check the MAF sensor/IAT wires as they can be damaged.
- Ohm-measure the Intake temperature sensor and make sure they are the same as your repair manual suggests. If you can find that the ohms are not correct, replace the sensor and remove the trouble codes.
- If the sensor seems correct, check and measure the sensor’s wirings and the engine control unit.
IAT Sensor Replacement Cost
An intake temperature sensor costs 20$ to 150$, and the labor costs 20$ to 100$. You can expect a total of 40$ to 250$ for an intake temperature sensor replacement.
If your intake temperature sensor is integrated into the MAF sensor, the part cost can increase rapidly. Some MAF sensors cost up to 400$.
The replacement of a MAF sensor or intake temperature sensor is often very straightforward and can often be made yourself with basic knowledge.
In some cars the IAT sensor can be located under the manifold in a difficult location, but this is quite rare.
Hi, I’m Magnus, the owner and the writer of Mechanic Base. I have been working with cars for 10 years, specialized in diagnostics and troubleshooting. I created this blog because I was tired of finding false information on the web while looking for repair information. I hope you enjoy my content!