Mass airflow sensor Analysis

Mass Air Flow sensor (MAF) is one of the key components of an electronic fuel injection system in your car. It is installed between the air filter and the intake manifold of the engine.  The mass air flow sensor measures the amount of air entering the engine or the air flow.
Mass Air flow Sensor (MAF)
Mass Air flow Sensor (MAF)
In modern cars, an intake air temperature sensor or IAT is built in the mass air flow sensor. There are few types of air flow sensors, however, modern cars use a hot-wire type. Let's see how it works


MAF System
The Mass Air Flow Sensor measures the amount of air volume flowing into a car’s engine, and sends the Electronic Control Unit (ECU) a voltage that represents the airflow.
  • Currently the most common MAF sensor is the plug-in hot wire type which is located inside the intake air duct between the air filter and the throttle body. This consists of a heating resistor, intake air temperature measurement resistor (for compensating intake air temperature), intake air  temperature sensor, and control circuifollowingcd circuit board).
  • A portion of the intake air from the air cleaner is bypassed into the hot-wire measurement area, where the intake airflow volume is measured. The hot-wire type MAF Sensor responds to temperature changes in the heating element. Changes in the resistance value and current of the heating element are converted into proportional voltage in the control circuit, and then sent to the ECU to calculate the amount of engine intake air volume.
  • The intake air temperature sensor also detects the intake air temperature and outputs it to the ECU. Responding to this signal, the ECU judges the air density and corrects the fuel injection quantity.
Watch the video below for clearer understanding of the concepts

How to know mass airflow sensor is faulty in a car
The following are the symptoms of a bad mass airflow sensor:

  • Poor fuel economy
  • Car stalling and hesitation while accelerating
  • Unstable rev counter
  •  check light always on
  • Hard starting when cold
  • Abnormal engine sound (loud noise)
  • Engine frequently trip off.
Causes of these failures 
In some situations, mass airflow sensor begins to fail due to contamination caused due to oil or dirt entering the sensor. In both cases, if the mass airflow sensor becomes dirty, the fix is to clean it or replace it.


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