Have you noticed your car’s engine making a knocking sound? Or noticed a drop in acceleration?
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.
Signs of a Bad Intake Air Temperature Sensor
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.
1. Drop in Acceleration
Due to a faulty sensor, the PCM may think that the air outside is cold 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.
2. Hard Cold Start Condition
Some engines rely on a signal from the IAT sensor to initiate the cold start injector program. If the sensor sends the wrong information, the cold start injector might not work, resulting in a hard cold start.
3. EGR Valve Affected
4. Poor Fuel Economy
In normal conditions, the engine computer makes a constant adjustment in the fuel and air level mixture to ensure maximum fuel efficiency. The engine control unit relies on the information from the IAT sensor and if a false signal is sent, the fuel efficiency decreases significantly.
Diagnostic Trouble Codes Associated with the IAT
A damaged intake air temperature sensor usually triggers two trouble codes: P0112 or P0113.
- The P0112 code indicates that the IAT sensor is operating at a low voltage and reports a temperature of about 300 °F (149 °C).
- The P0113 code is caused by a high circuit voltage and means that the IAT sensor reports a temperature of about -38 °F (-39 °C).
What is an Intake Air Temperature Sensor?
The intake air temperature sensor or IAT sensor has the core function of monitoring the temperature of the air that is entering the engine of your vehicle. This information is very useful 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 in order to stabilize and regulate the air-fuel ratio for the combustion engine. As a result, it ensures optimum combustion and efficient fuel consumption.
The principal science behind evaluating these sensed readings is that the hotter air is lighter than the colder air in density, therefore the cooler air would need relatively more fuel in order to burn with the fuel that is injected in the engine.
If the fuel and air mixture ratio is not correct, the vehicle will not perform to its full capacity and the fuel consumption may also be increased.
With this information, the computer system of the vehicle automatically regulates the fuel injection by altering the injection pulse to inject more fuel when required. it is especially important to maintain the proper air-fuel ratio during the hot winds of summer as well as the cool nights of winter as the temperature extremes can greatly affect the performance of your vehicle by changing the density of the air that is entering the vehicle. It is also very helpful in maintaining the emission levels of your vehicle.
Where Is the IAT Sensor Located?
The location of the intake air temperature sensor is not standard due to different locations in a variety of designs. The best way to locate the IAT sensor in your vehicle if to refer to the service manual that is provided by your manufacturer.
The intake temperature sensor is often integrated into your mass air flow sensor!
Diagnosing a Bad or Failed Air Intake Temperature Sensor
The diagnostic procedure of checking if the IAT sensor has failed is relatively easy, and you can do it yourself if you have some basic knowledge and the tools available to you.
You will usually require a multimeter, a scanning tool, a wire piercing probe, and some tools to reach it. it is better if you test and diagnose the problem before attempting to replace the IAT sensor. Here is a quick step by step guide that you can follow to diagnose a bad IAT sensor.
- Keep the service manual of your vehicle with you.
- Locate the sensor and clean the area with brake cleaner or something similar.
- 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 temperature of the engine.
- If the readings are not realistic, there could be a problem with your IAT sensor or the wirings to it.
- Try to clean the intake air temperature sensor carefully with brake cleaner or electric cleaner.
- Make sure that the connections are correct and the wiring is in good condition.
- Check once again if the readings are fixed with your OBD2 scanner.
- If the readings change, there might be corrosion inside the connector for the IAT/MAF sensor.
- If the temperature is over 300 degrees or does have a low unrealistic value, check the wires of the MAF sensor/IAT as they can be damaged.
IAT Sensor Replacement or Adjustment
Since the air temperature sensor is a solid-state component, it cannot be adjusted. However, you can clean the sensor if it is dirty or clogged and it will be in a good working condition again. To clean the sensor, remove it from the intake manifold then use an electronic cleaner to spray the affected area.
Avoid using any other type of cleaner as it can damage other components or plastic housing.
Installing a New Air Temperature Sensor
Installing a new IAT sensor is fairly simple and requires some basic tools, including a pair of gloves, a new IAT sensor, and safety glasses.
- Step 1: Start with locating the IAT sensor which can be found in the air intake boot, at the intake manifold or integrated with the MAF sensor.
- Step 2: Disconnect the negative terminal of the battery.
- Step 3: Inspect the IAT sensor and remove its electrical connector.
- Step 4: Remove the IAT sensor by either pulling it straight or unscrewing it.
- Step 5: Install the new IAT sensor.
- Step 6: Reconnect the electrical connector and the battery terminal.
IAT Sensor Replacement Cost
The average replacement cost of an IAT sensor is between $60 and $110. The labour cost is between $20 and $70, while the parts itself cost between $100 and $150.
The cost of an IAT sensor replacement can vary greatly depending on the type and the manufacturer of your vehicle when you are buying the parts. On average, for most vehicles, you will have to pay a sum of $163 for the replacement of an intake air temperature sensor.
The price range for most vehicles on average is between $80 to as much as $270. For some vehicles, you can get the replacement part for as low as $7 while all the other added costs of around $100 to $150 would be for the mechanic and labour cost. This greatly varies with the mechanic you are dealing with. By doing it yourself following an easy to replace guide, you can save on all the labour cost involved.