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Mass Air Flow Sensor

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Mass Air Flow Sensor at 1A Auto

What is a Mass Air Flow Sensor and where is it Located?

The majority of vehicles on the road today are equipped with a mass air flow sensor (MAF), also commonly referred to as an air flow meter. The mass air flow sensor is a device that measures the amount of air entering the engine and supplies this information to the engine control unit (ECU). The ECU uses this information to calculate engine load, which the ECU uses along with information provided by the oxygen sensor(s) to precisely control the engine’s air / fuel ratio. Engine load measurement is also needed to control other functions such as automatic transmission shift points on many vehicles. 

Your vehicle’s air flow meter is located between the air filter and throttle body, along the air intake stream. The appearance of the MAF sensor will differ depending on what kind of sensor your vehicle uses, as there are a few different types of mass air flow sensors commonly used on cars and trucks.

Hot Wire Mass Air Flow Sensors

One of the more common mass air flow sensors used today is the hot wire sensor. This type of MAF sensor measures air mass directly. It uses an electronic control unit, a temperature sensor, and an electronically heated wire(s). This wire is heated and maintained at a certain temperature. As engine load increases, air passes through the sensor cooling the wire. In turn, more voltage is needed to bring the wire back to temperature. This voltage is directly related to the mass of the air entering the engine.

Cold Wire Mass Air Flow Sensors

Many General Motors vehicles use a cold wire MAF sensor. This sensor works just like a hot wire sensor, however it uses a “cold wire” that supplies the ECU with the ambient air temperature. This information is useful because different air temperatures will cool the hot wire at different rates.

Karman Vortex Mass Air Flow Sensors

Karman vortex air flow meters do not directly measure mass air flow. These meters measure air temperature, pressure and volume. The ECU uses these three measurements to calculate the mass air flow. This type of meter uses a metal foil mirror, a vortex generator, and a photo receptor. The vortex generator disrupts the air, creating what is known as a Karman vortex. The frequency of these vortices or “swirls” is directly related to the speed of the air. These sensors also incorporate an internal temperature sensor and barometric pressure sensor.

Vane Air Flow Meters

A vane air flow meter (also known as a “flap style” meter and a VAF sensor) is an early type of air flow meter that measures air intake volume. This type of meter uses a spring loaded flap which is attached to a variable resistor. As air enters it pushes against the flap or plate opening it. The movement of the flap opening is converted to voltage and the signal is sent to the ECU. VAF sensors also contain an intake air temperature sensor.

How do Mass Air Flow Sensors / Meters Fail?

Regardless of the type of MAF, they are all vulnerable to dirt or debris. If contaminated, these sensors are unable to provide the ECU with accurate information. Keeping up with scheduled maintenance, inspecting and replacing a dirty or clogged air filter is crucial. Hot and cold wire MAF sensors are particularly prone to dirt and oil contamination, as well as moisture. Although it is possible to clean a mass air flow sensor, using a cleaner specifically made for MAF’s, it is important to remember the components are particularly fragile and can be easily damaged. It is widely recommended to replace a faulty MAF sensor rather than clean it. 

Common symptoms related to a failed or faulty mass air flow meter is an erratic idle, stalling or inability to hold idle, loss of power, reduced gas mileage, bad throttle response, or even a no-start condition. When diagnosing a faulty mass air flow sensor it is important to check for oil or dirt contamination, intake leaks after the sensor (such as cracked / broken vacuum lines, air intake hose, throttle body or intake manifold leaks), and broken or frayed wiring. All mass air flow sensors and meters can be tested on or off the vehicle by a variety of methods, although methods differ depending on application. Common OBDII Trouble Codes related to mass air flow sensors / meters include:

P0100 - Mass Air Flow Circuit Malfunction
P0101 - Mass Air Flow Circuit Range/ Performance Problem
P0102 - Mass Air Flow Circuit Low Input
P0103 - Mass Air Flow Circuit High
P0104 - Mass Air Flow Circuit Intermittent
P0170 - Fuel Trim Malfunction (Bank 1)
P0171 - System Too Lean (Bank 1)
P0172 - System Too Rich (Bank 1)
P0173 - Fuel Trim Malfunction (Bank 2)
P0174 - System Too Lean (Bank 2)
P0175 - System Too Rich (Bank 2)

Need a Mass Air Flow Sensor Replacement?

Air is a key ingredient in fuel combustion and as such, an automotive engine’s air / fuel ratio needs to be at an optimal level to run efficiently. It is the job of the MAF sensor to measure the amount of air entering the engine and send that information to your vehicle’s computer so that the ECU can adjust the mixture of air and fuel properly depending on how light or heavy the engine’s current air supply is. If the ECU is provided with the wrong information due to a malfunctioning air flow meter, it could release an improper amount of fuel into the engine, which is not something you want to occur. Therefore, having a working mass air flow meter on your vehicle is extremely important.

If your engine is not running properly because of a defective air flow meter, 1A Auto has your answer – we are your source for a mass air flow sensor replacement! We have quality, aftermarket mass air flow sensors for many makes and models, and all at great prices.

1A Auto MAF Sensor Features:

  • - Strict quality control specifications ensuring you receive a durable sensor
  • - Compare a 1A Auto air flow sensor to an OEM sensor and save 30-50%
  • - Direct replacement mass air flow sensor for convenient installation

At 1A Auto, shopping for an aftermarket mass air flow sensor replacement for your car, truck, SUV or van is easy - we're here to help you select the right one for your vehicle! Call our customer service toll free at 888-844-3393 if you have any questions about our aftermarket sensors, warranty, compatibility or to purchase, or you can buy online. Recover your vehicle's lost power and fuel economy; replace your air flow meter today! For answers to some of the more frequently asked questions about our aftermarket mass air flow sensors and MAF sensors in general, please see our FAQ section below.

Frequently Asked Questions About Mass Air Flow Sensors:

1. In short, what does a mass air flow sensor do?

As mentioned above, the MAF sensor provides information to the engine control unit (ECU) about the quantity of air entering the engine. Using this information, the ECU calculates how much fuel to supply to the engine for optimal combustion.

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2. Quickly, what are the symptoms of a bad air flow sensor?

  • - Rough Idle
  • - Power Loss
  • - Reduced Gas Mileage
  • - Hard Starting
  • - Stalling at slow speeds

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3. I replaced the air flow sensor, but the check engine light is still on, what should I do?

Replacement of the air flow meter rarely results in an instant shut off of the check engine light. If your check engine light is still on after replacement but the engine is running correctly, the light will probably go off after a few cycles of driving with the new sensor (on some vehicles this could take as many as 50 cycles of turning the key on and off). You can also have the code cleared with the correct scan tool. Another possible remedy is to disconnect and reconnect the battery, although this may not work on all vehicles.

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4. Will this sensor fit my vehicle?

Information regarding the makes / models that a 1A Auto mass air flow sensor replacement will fit can be found, in bold, near the bottom of each individual part page. Please double check this information before you make your purchase. Call our friendly customer service reps at 888-844-3393 if you should have any additional questions.

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5. In short, where is the mass air flow sensor located?

Usually it can be found inside the air intake duct between the air filter and the engine.

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6. Can I install the mass air flow sensor myself?

That depends on the amount of familiarity you have with automobiles and the tools you have available. It's usually a simple process; first find the sensor, then disconnect the negative battery cable. Disconnect the wiring harness and vacuum hose. Remove the screws/bolts holding the sensor in place and take out the old sensor. Reverse the process to install.

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