8 Signs and Costs of a Bad MAF Sensor

For car engines to work properly, the Mass Air Flow Sensor is crucial. It determines how much air is entering your car engine. The engine control module then uses this data to set the maximum fuel level for the engine injectors.

Sometimes, the MAF sensor can become worn out or damaged. This article will cover the causes, whereabouts, and cost of replacing an MAF sensor.

8 Signs Your MAF Sensor Is Not Working

Common signs of a defective mass airflow sensor include a check engine lamp on the dashboard, and problems with engine performance.

One of the main signs that a MAF sensor is failing or not working properly is:

Every problem that may occur with your engine's mass airflow sensor could cause performance to be affected. This is a detailed listing of symptoms that indicate a poor mass flow sensor.

Check Engine Light Illuminates

Engine control modules monitor all sensor data to make sure everything works properly. An error in a sensor's signal will cause the ECM or the PCM to turn on the check engine light.

Therefore, if your MAF sensor is faulty and sends wrong information to the engine control unit – the check engine light will illuminate your dashboard.

The engine control module may not recognize an MAF sensor that is defective. This means it could still be deficient even though there are no indicators on the dashboard. If your engine check light is not working, you should first check for diagnostic trouble codes using an OBD2 scanner.

Slow Acceleration

To achieve optimal performance your engine must have a proper air-fuel combination in the combustion chamber. Failing MAF sensors can result in a poor air-fuel mix and can have a wide range of performance issues, including slow acceleration.

You may notice a slowing down in your vehicle than you are used to. This could be a sign that your MAF sensor might be at fault.

Related: Is your car losing power when you accelerate? (Here’re the Causes)

Hesitation or rough acceleration

You may also notice jerky acceleration due to a bad MAF sensor.

This is usually because the air-fuel mixture becomes too lean, so the car engine “starves” due to lack of food, and this will cause it to jerk.

It can cause acceleration problems if the mixture of air and fuel is too dense.

RELATED: Does your Car jerk while you are accelerating? (Here’s How To Fix it)

It is a difficult condition to start

It is possible that the sensor in your air conditioner is failing, making it more difficult for you to get started each morning.

Car engines respond very well to the correct airflow mix at the precise moment of starting. The wrong fuel can cause your engine to not turn on or crank slightly longer than normal.

RELATED: Car Hesitates to Start – Causes & How to Fix

The Exhaust Pipe Makes Black Smoke

If you see black smoke coming out of your exhaust pipes, it is likely that your engine consumes too much fuel. Therefore, if you realize that a lot of black smoke is pouring out of your exhaust pipe – there is a significant risk that your engine runs too rich, which a bad MAF sensor could cause.

If the engine runs richer, it may also cause a bit more grey smoke to come out of your exhaust pipe. You should also fix your catalytic converter as this can cause serious damage.

Rough Idle

The car engines’ most sensitive situation for engine problems is at idle and during the starting moment. Problems are likely to occur during idle.

If your idle has become very rough lately or if the engine is stalling – there is a big risk that your MAF sensor has gone bad.

RELATED: Rough Idle Causes & How to Fix it

Mistakes

When one or more of the cylinders fails to burn fuel, misfires can occur. To burn the fuel correctly, the engine needs 3 things – the right air-fuel ratio, ignition, and compression.

If the mixture of air and fuel exceeds specifications, this may result in one or more cylinders failing to ignite. This will lead to the engine not igniting correctly, which can cause a misfire. You may find trouble codes that indicate misfires. This could be caused by a defective mass air flow sensor.

RELATED: 6 Symptoms of an Engine Misfire (& 7 Common Causes)

Energy consumption for alternative fuels

The last sign is the most apparent. This is because you know that your MAF sensor has failed, resulting in a defective mixture of air and fuel. Failing MAF sensors can lead to fuel consumption going up or down.

You may think that reduced fuel consumption is a good thing – but it can actually damage your engine, which will make it more expensive in the long run.

Locate the MAF Sensor

The MAF sensor can be found on the long hose connecting the intake manifold to the filter box. It is often mounted on the filter box.

The exact position of the sensor will vary from one manufacturer to the next, depending on how the engine is designed.

For a fast search, you could use an internet-based repair manual. The pictures will give you a hint as to its location.

Clean a dirty MAF sensor

The sensor head often becomes clogged with dirt and other debris. This can lead to problems in the mass flow sensor. Poor performance can be caused by the accumulation of dust particles.

The MAF sensor can be cleaned easily. Just remove the sensor head from the MAF sensor housing and carefully clean the sensor’s hot wire with an electronic cleaner or a specific MAF sensor cleaner like this one:

However, the sensor’s hot wire is very sensitive and you can easily damage it therefore you don’t want to touch it with your hands or with a towel! Spray it with water and allow it to dry.

Diagnose a Failing Mass Air Flow Sensor

It is common for MAF sensors to be very expensive. Therefore, it is crucial to do a proper diagnosis and replace any damaged MAF sensors.

It is usually easy to diagnose a MAF sensor if you have a good understanding of what to look for. To diagnose the MAF sensors correctly you will need to have measured correctly for each car model and engine. This can be done by consulting a repair manual.

1. Use an OBD2 scanner to check live data from MAF sensors on idle. You should have 0 mg.
2. Check the MAF sensor values again by starting the car. You should see the MAF sensor readings change as you rev your engine. It should rise when the engine is turned up and decrease as engine RPM drops. If it is not stable, either the diagnostic tool or MAF sensor are at fault.
3. Check for corrosion by removing the connector from the MAF sensor.
4. For measurements of the sensor and wirings, refer to your repair manual. Learn more This video shows you how to check the MAF sensor.
5. If the sensor is defective, clean it or replace it.

Repair of MAF Sensor

It costs between $140 to $550 to replace an MAF sensor, depending on what car you have and how much labor is required. Mass air flow sensors cost between $100 and $400, and labor costs can range from $40 to $150.

The cost of the MAF sensors can often be very high. You may have to also replace the entire MAF housing, or even the sensor.

For most cars, replacing the MAF sensor is easy and takes less than 10 minutes. This can be done easily even if you have no car knowledge.

FAQs about the MAF Sensor