What is a MAF sensor, common problems and solutions

What is a MAF sensor?

As a critical part responsible for injecting fuel into your car system, the MAF also plays a vital role in calculating the engine’s air consumption.

The PCM (powertrain control module) then uses that information to determine the amount of fuel to optimize the ratio between air and oil for ideal performance.

The location of the MAF sensor is between the car engine’s intake manifold and the air filter. Notably, there are different airflow sensors, and most have unique maintenance requirements. Essentially, there are analog and digital airflow sensors.

Though they have one function, they operate differently. The analog airflow sensors work by producing variable voltage output while the digital sensors send frequency output.

Depending on the mass airflow sensor on your car, these outputs are sent into the car’s automatic transmission to regulate the air-fuel mixture for optimal performance.

Mass airflow sensors measure the volume of air entering the cylinders.

Depending on this information, petrol engines determine the amount of fuel to be injected, whereas diesel engines calculate how much flue gas is returned to the cylinders by their EGR systems.

How does a MAF sensor work?

You should know that most of these mass airflow sensors operate based on the hotwire principle. As previously mentioned, it’s housed between the Manifold and the air filter.

A typical MAF sensor has two sensors sensing wires. But only one is heated by an electrical current as the air flowing through the heated wire cools down.

There’s a certain temperature maintained between the two wires. When there’s a change in the temperature difference, the MAF automatically may decrease or increase the electrical current to the hot wire for compensation.

The electrical current changes to a frequency that the sensor sends to the PCM, which the PCM interprets as airflow. After that, the air entering the engine is adjusted to match the fuel required for burning.

Symptoms of a faulty MAF sensor

A faulty MAF sensor can be a pain in the neck, especially if you don’t know how to diagnose your car’s sensor properly. Essentially if this car component fails, the engine won’t be able to determine the ideal amount of fuel to inject for burning. Below are some common tale-tell signs that your Mass airflow sensor has a problem.

1. Emission of excess exhaust fumes and black smoke

If your car emits excessive exhaust fumes, it may be a red flag for a faulty MAF sensor. Primarily, this is because of the incorrect mixture ratio of oil and air. That also means the PCM is receiving wrong signals from the MAF.

Additionally, suppose your vehicle is also emitting black smoke in the exhaust. That means the engine is burning too much fuel due to the disproportionate air-fuel mixture ratio in the combustion chamber.

Once you notice a strong fuel smell in the exhaust fumes, that may mean incomplete combustion. If your vehicle is experiencing the above shortcomings, it’s time to replace the MAF sensor.

2. Excessive fuel consumption

As pointed out above, a strong fuel smell in the exhaust fumes means incomplete combustion in the engine. And so, you’ll notice that your car will be running out of gas faster than usual.

That’s because the powertrain control module sends out wrong signals causing poor and faster fuel burning in the engine.

3. The car may be jerking

Another sign of a faulty MAF sensor is unusual power jolts or hesitation in the car’s movement. Usually, this may occur if you’re driving at high speed on a highway or a ramp.

Driving a car with a faulty MAF sensor expelling these power jolts is very dangerous. It’s advisable that once you’ve noticed such a problem, have an auto repair mechanic look at it immediately.

4. Low or high RPM

If your car’s sensor constantly gives inaccurate information about the fuel-air ratio, the air entering the engine may cause serious problems.

Furthermore, this problem is hardly noticeable. Low or high RPM is probably the cause once your automobile starts demanding more gas than usual.

Since it’s hard to notice it, a mechanic will use a scanner to check for this problem. Note that replacing the MAF sensor may not solve this issue if the problem is at the circuit level.

So it’s crucial to diagnose the entire MAF unit properly. If your car’s MAF sensor fails, it won’t send the correct information to the PCM. That means the engine won’t work properly or may malfunction.

5. It can be difficult to start the car

If your car is having trouble starting, that’s probably due to a faulty MAF sensor. You should know that starting a car requires a lot of gas. So, generally, a faulty MAF sensor means the PCM isn’t injecting enough fuel to prompt the car to start.

6. Low engine power.

A bad MAF sensor may be due to low engine power

7. Check engine light goes on

Obviously, the above symptoms usually trigger the check engine light to be lit on the dashboard.

The above symptoms are some of the most obvious ones—others to look out for include; clogged air filters, broken intake tubes, and restricted exhaust.

Conclusively, you should check the entire intake system to ensure none of these problems are causing the above-highlighted symptoms.

Solutions to fix MAF sensor problems

Solving problems associated with MAF sensor complications begins by identifying the symptoms. If you’ve canceled out all the car’s intake system issues but still face problems with the MAF sensor, the following options might help.

  • Blow the intake tube first to expel dust, then install a new filter to prevent dust from blocking the system
  • The problems may also arise from the contamination of the MAF sensor. You can use the specified MAF sensor cleaner, an alternative way to expel the complications.
  • As a last resort, if you’re sure nothing is working, you’ll have to replace the MAF sensor.
  • If the problems aren’t solved with the above solutions, including MAF sensor replacement, something else may be faulty in your car. You should consult an automobile expert unless you prefer to purchase a new vehicle.

To determine the correct functioning of the circuit before changing the sensor, a complete diagnosis should be conducted. Changing the sensor won’t solve the problem if the problem is at the circuit level.

A malfunctioning MAF sensor will not transmit information related to airflow to the PCM. As a result, fuel level information that would otherwise be transmitted cannot be used to regulate the fuel level.

This results in a possible engine failure. Therefore, a sensor replacement is necessary.

Frequently Asked Questions

What are the components of a MAF sensor?

It comprises a case fixed between the air pipe and the air filter. In this case, it is where the sensor is screwed or attached. The sensor itself consists of electronics and a hot film meter. Generally, the MAF sensor measures the air flowing into the engine and then relays that information into the control unit.

What’s the difference between the MAF sensor and air volume sensor?

There is no difference between the two terms as they mean the same thing. Other terms for this car unit include; HFM, Airflow sensor, and hot film meter.

Why is the MAF sensor a Necessity?

The primary role of the MAF sensor is to measure the mass of the air flowing into the engine and then relay that data to the control unit, which is used in determining the amount of fuel to burn.

Note that 14.7kg of air is the ideal amount the engine requires to burn 1kg of fuel optimally. So, the MAF plays a significant role in ensuring your car runs smoothly.

MAF sensor common error codes on OBD2

P0100 Mass Air Flow (MAF) Circuit Malfunction – problems with the flow meter or the circuit. Other related errors are P0101, P0102, P0103, and P0104.

Easy solutions to use for MAF dashboard errors:

  • it’s easier to reset the code to see if it reappears.
  • disconnect the sensor and connect it again
  • check the voltage reaching the sensor (differs from the engine to engine, check the technical book of the car)
  • replace the sensor
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