IAT Sensor Buyer's Guide
- The Intake Air Temperature (IAT) sensor, also known as an air charge temperature sensor, is a device that monitors the temperature of air that flows into the engine.
- It is typically mounted between the air intake box and the throttle valve housing. In vehicles that have Mass Airflow (MAF) sensors, the IAT sensor may be built into the same component.
- The IAT sensor provides the engine computer the necessary information to properly regulate the engine’s air-to-fuel ratio.
- For example, cold air is known to be denser than hot air, which means lower temperature readings require more fuel to be pumped for the proper fuel mix.
- In vehicles that have three IAT sensors, the other two sensors can relay signals used to regulate your car’s climate control systems. One sensor will measure outside air temperature, while the other checks the temperature inside the passenger cabin.
- The cost of an IAT sensor will vary depending on your vehicle’s specific year, make, and model. OE replacement IAT sensors will generally cost you anywhere between $3 and $111. This part is sold individually.
- Common symptoms of a bad IAT sensor include: Check Engine Light is on, difficulty starting your vehicle, poor drivability, and reduced fuel economy.
- To prevent damage and costly repairs to the engine and other key vehicle systems, it is best to replace a faulty IAT sensor immediately.
What is an IAT sensor?
The Intake Air Temperature sensor (IAT sensor), also known as an air charge temperature sensor, is a device that monitors the temperature of air that flows into the engine. This information is used by the Powertrain Control Module (PCM) to calculate air density and produce the optimal air-to-fuel mixture in the engine.
Where is the IAT sensor located?
You can locate the IAT sensor by looking under the hood and checking the air duct at your vehicle’s rear intake manifold. It is typically mounted between the air intake box and the throttle valve housing. In vehicles that have Mass Airflow (MAF) sensors, the IAT sensor may be built into the same component.
How does an IAT sensor function?
The IAT sensor provides the engine computer the necessary information to properly regulate the engine’s air-to-fuel ratio. Air temperature is used as a gauge in calculating the density of air that is sucked into the engine. This is important because it affects the concentration of oxygen molecules per square inch.
Depending on the result of these temperature readings, the control module can decide whether less or more fuel needs to be injected into the combustion chamber to maintain optimal engine performance. For example, cold air is known to be denser than hot air, which means lower temperature readings require more fuel to be pumped for the proper fuel mix.
To get more technical, let’s take a closer look at the device itself. The IAT sensor sends signals to the PCM in the form of electrical resistance. The PCM sends a 5-volt reference to the IAT sensor and the latter sends this signal back to the PCM. Since it is designed as a thermistor, its electrical resistance changes with any change in temperature. Higher temperatures will produce lower resistance values, while lower temperatures result in higher resistance.
In vehicles that have three IAT sensors, the other two sensors can relay signals used to regulate your car’s climate control systems. One sensor will measure outside air temperature, while the other checks the temperature inside the passenger cabin.
How much does replacing an IAT sensor cost?
The cost of an IAT sensor will vary depending on your vehicle’s specific year, make, and model. OE replacement IAT sensors will generally cost you anywhere between $3 and $111. This part is sold individually.
When replacing this device, keep in mind that some vehicle engines may need more than one IAT sensor. You may replace and install this part on your own or with the help of a trusted mechanic.
Symptoms of a bad IAT sensor
Here are some common IAT sensor symptoms that you should look out for.
Check Engine Light is on
One of the things that will alert you of trouble with your IAT sensor is the Check Engine Light on your dashboard. Your car’s computer generates an error code that triggers this warning light when it detects that your IAT sensor is malfunctioning. All you need to do is use an error code reader to find out if the light was triggered by an IAT sensor issue.
Difficulty starting your vehicle
A bad IAT sensor will make it more difficult to start your vehicle in the colder months. If the IAT sensor makes a faulty reading and reads a temperature higher than actual conditions, not enough fuel will be injected into the engine for it to achieve the proper air-to-fuel ratio to start.
How your vehicle drives can also be affected by an IAT sensor malfunction. You may experience stalling, rough idling, and random surges of power because of the inaccurate temperature readings from this sensor.
Reduced fuel economy
Inaccurate readings from the IAT sensor can trick the engine computer into injecting more fuel than necessary. Aside from being costly and wasteful, unburnt excess fuel can have a negative impact on your engine health, as well as your exhaust system. You should consider having this sensor checked if your car suddenly consumes more fuel than it normally does.
Causes of IAT sensor failure
There are several things that can cause your IAT sensor to fail. Due to its location, carbon and oil deposits may build up at the tip of the sensor and reduce its responsiveness. Aside from normal wear, exposure to extreme temperatures can reduce its functionality over time. It may also cause problems when electric connectors are shorted or if they incur corrosion damage. To prevent costly repairs to the engine and other key vehicle systems, it is best to replace a faulty IAT sensor immediately.
Finding the right fit
Choose the right IAT sensor for your car by using our website’s built-in vehicle selector. Simply type in your vehicle’s correct year, make, and model to narrow down your search results to all compatible parts.
Choosing the Right IAT Sensor
Have you noticed a decrease in your car's fuel economy? Is it usually sluggish during acceleration? Or worse, does your car sense your engine overheating when it really isn't? Then this is a case of a faulty IAT sensor. Though this part is relatively small, finding the perfect one for your car is a tedious process. As a guide, here are just some of the dos and don'ts when shopping for a new IAT sensor:
- Consult with your local mechanic to know the specific type of IAT sensor your vehicle requires. If you don't know any, you can also find out on your own by researching and looking through your old part. Use the serial number of the old one and bring it to your dealer to know which kind of IAT sensor is perfect for your car. Serial numbers found on IAT sensors usually contain information on the right size, type, and application used. You can also bring the old sensor with you for comparison when shopping. Since this a very sensitive electrical component of your car, checking the different connections and configurations is essential to ensure you don't get the wrong kind of sensor.
- Go through sensor diagnostics to determine if the IAT sensor you wish to purchase is working well. It should be able tests for high electrical performance and durability. This will ensure that your sensor will function efficiently under any kind of condition. Since it is located deep within your compartment, it will be exposed to various elements such as heat, debris, and oil. You want your IAT sensor to last for a long time. Testing the part before purchasing can also avoid premature wear, poor engine performance, decreased fuel economy, and overheating.
- Make sure your new IAT sensor comes with manufacturer's instructions for correct installation. This is especially true if you want to do the installation yourself. Follow the guide well to ensure that it works well with the rest of your engine compartment.
- Don't replace your IAT sensors with ones that are advertised to alter the temperature readings inside your air duct. This kind of sensor is recently making its waves in the market, especially for drivers who want a more powerful engine. It is considered to be one of the cheaper
performance chip upgrades. What it does is that it claims the air is cold and dense when it really isn't', resulting in your engine to burn more fuel than is necessary. Although it does boost engine power, it decreases fuel economy and can even result in harmful emissions. If you don't want to waste money on gas, get the right kind of sensor.
- Don't purchase aftermarket IAT sensors. In order to complement with the mechanics of your engine, be sure that your sensor is engineered to meet OE specifications. OE manufactured parts are always recommended to ensure that it fits well with your car and that it is made with strict quality control standards.
- Don't settle for IAT sensors without warranties. The standard warranty coverage for most IAT sensors is 90-day or 3,000-mile coverage. So always check what kind of terms your dealer offers. Make sure that you make the most out of the part by having the option of replacing it if it doesn't work as expected.
How to Install your New IAT Sensor
Modern cars are more like computers than machines. They are made up of various systems and programs that help make your car operate faster and smarter. One of these "smart programs" is your IAT sensor. Responsible for monitoring the air in your engine block, the IAT sensor is one of the most important innovations in the auto industry. But no matter how advance these sensors are, they can still malfunction. So when your this part starts to fail, be sure to replace it ASAP to prevent your engine from running poorly.
Difficulty level: Easy to moderate
Tools you'll need:
- New IAT sensor
Step 1: Preparing your car
Park your car in a flat area or at your garage. Open your hood to locate your IAT sensor.
Step 2: Locating the IAT sensor
The IAT sensor is found on the air intake duct. If you still can't find it, you can simply follow your intake air hose, which is found in the air cleaner assembly, to the sensor.
Step 3: Removing the sensor from the air intake system
Once you've located your sensor, remove the electric plug connected to it. Unscrew the sensor and gently pull it out from the duct.
Step 4: Positioning your new sensor
Place your new IAT sensor into your air intake duct and push it in.
Step 5: Installing your new sensor
Take the electric plug in step 3 and reconnect it to your new sensor.
Step 6: Finishing touches
Your installation is complete and you can now close the hood of your car.
Step 7: Test-driving your new sensor
Start your engine to begin testing your new IAT sensor.
Note: For any difficulties with the steps mentioned above, you can also refer to your vehicle owner manual. Also note that removal, installation, and maintenance of this part varies with the car's make and model.