8 Symptoms Of A Bad MAF Sensor (& Replacement Cost) (2022)

The Mass Air Flow Sensor (MAF) is an important part for car engines to function properly. It measures how much air enters the car engine and then sends this information to the engine control module, which then controls how much fuel the fuel injectors should inject into the engine.

Unfortunately, it sometimes happens that the MAF sensor gets worn or bad. In this article, we will talk about the symptoms of a bad MAF sensor, location, and replacement cost.

8 Bad MAF Sensor Symptoms

The most common symptoms of a bad mass airflow sensor are a check engine light on your dashboard and engine performance issues.

The main symptoms of a bad or failing MAF sensor include:

  • Check Engine Light Illuminates
  • Slow Acceleration
  • Hesitation, rough or jerky acceleration
  • Hard Starting Condition
  • Black Smoke From Exhaust Pipe
  • Rough Idle
  • Misfires
  • Changed Fuel Consumption

Because the mass airflow sensor is directly connected to the engine control system, any problem can interfere with performance. Here is a more detailed list of the most common symptoms of a bad mass air flow sensor:

Check Engine Light Illuminates

8 Symptoms Of A Bad MAF Sensor (& Replacement Cost) (1)

The engine control module monitors all sensors in the car engine to ensure that everything is OK. If a sensor sends an incorrect signal, the ECM or PCM will turn on the check engine indicator 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.

However, the engine control module does not always recognize a faulty MAF sensor, so it may still be defective even if there is no engine light on your dashboard. But, if your check engine light is illuminating you want to check the diagnostic trouble codes first with an OBD2 scanner.

Slow Acceleration

Your engine needs a perfect air-fuel mixture in the combustion chamber for optimal performance. A faulty MAF sensor can cause a faulty air-fuel mixture and it can cause many strange performance issues with your car and slow acceleration is one of them.

If you notice that your car is much slower than usual, there is a significant risk that your MAF sensor is at fault.

RELATED: Car Losing Power When Accelerating? (Here’re the Causes)

(Video) 8 Symptoms of bad Mass Air Flow Sensor, MAF Sensor

Hesitation, rough or jerky acceleration

As you may suspect, a faulty fuel injection caused by a poor MAF sensor can also make your acceleration rough or jerky.

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.

If the air-fuel mixture is too rich, it can also extinguish the ignition created by the spark plug, which causes the acceleration to be rough.

RELATED: Your Car Jerks When Accelerating? (Here’s How To Fix it)

Hard Starting Condition

If you notice that your car has become more difficult to start in the morning, there is a chance that a bad air mass sensor is causing the problem.

All car engines are very sensitive to the right airflow mixture at the exact starting moment. If the wrong amount of fuel is injected into the engine at the moment, your car may not start at all or just crank a little longer than usual.

RELATED:

Black Smoke From Exhaust Pipe

Black smoke from the exhaust pipe is a strong sign that your engine is getting too much amount of fuel compared to the amount of air. 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.

You can also notice a little more gray smoke from the exhaust pipe than usual if your engine runs rich. This can also damage your catalytic converter, which is very expensive so you definitely want to fix it as soon as possible.

Rough Idle

The car engines’ most sensitive situation for engine problems is at idle and during the starting moment. Therefore, it is very likely that problems will occur at idle also.

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:

Misfires

Misfires occur when one or more cylinders fail to burn the fuel. To burn the fuel correctly, the engine needs 3 things – the right air-fuel ratio, ignition, and compression.

(Video) MASS AIR FLOW SENSOR SYMPTOMS

Therefore, if the air-fuel mixture is very far beyond the specifications, it may cause one or more cylinders not to ignite at all, and this will cause the engine to ignite incorrectly, causing a misfire. If you find any trouble codes related to misfires, it can be a sign of a bad mass air flow sensor.

RELATED:

Changed Fuel Consumption

This last symptom is probably the most obvious because you already know that a faulty MAF sensor is causing a faulty air-fuel mixture. Therefore, a faulty MAF sensor can cause fuel consumption to either go 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.

MAF Sensor Location

8 Symptoms Of A Bad MAF Sensor (& Replacement Cost) (2)

The MAF sensor is located on the large hose between the intake manifold and the air filter box, often installed on the air filter box.

Its exact location varies from manufacturer to manufacturer, as they fit the sensor based on the engine design.

You can use a repair manual to find the exact location or use the internet for a quick search. Check out the pictures for a clue as to where it can be placed.

Cleaning a Dirty MAF Sensor

Often, the problems associated with the mass air flow sensor occur due to dirt and debris buildup on the sensor head. This particle accumulation over time results in poor performance of the sensor.

Cleaning the MAF sensor is often relatively straightforward. 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:

Sale

8 Symptoms Of A Bad MAF Sensor (& Replacement Cost) (3)

3,224 Reviews

(Video) Bad Mass Air Flow Sensor - Symptoms Explained | Signs of failing / dirty mass air flow sensor in car

CRC 05110 Mass Air Flow Sensor Cleaner - 11...

  • Increases Horsepower And Improves...
  • Plastic Safe-Dries In Seconds
  • Not Voc Compliant For California & Otc
  • Use Every Time You Clean Or Change Your...

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! Just spray it and let it dry, it should be enough!

Diagnosing a Failing Mass Air Flow Sensor

8 Symptoms Of A Bad MAF Sensor (& Replacement Cost) (4)

MAF sensors can often be quite expensive, and therefore it is important to make a correct diagnosis before choosing to replace the MAF sensor.

Diagnosing a MAF sensor is often relatively easy if you know what to look for. But to diagnose the MAF sensor correctly, you must have correctly measured values for your specific car engine and model, which you can find in a repair manual.

  1. Connect an OBD2 scanner and check the live data from the MAF sensor on idle. It should be 0 mg.
  2. Start the car and check the values from the MAF sensor again. It should go up when you rev the engine and down as the engine RPM decreases; if the value is stable, there is either something wrong with your diagnostic tool, MAF sensor, or the wirings to it.
  3. Remove the plug to the MAF sensor and check for corrosion.
  4. Check your repair manual to measure the sensor and the wirings to it. You can find out more about how to test the MAF sensor in this video.
  5. Clean or Replace the MAF sensor if faulty or repair the wirings.

MAF Sensor Replacement Cost

The average MAF sensor replacement cost is between $140 and $550, depending on the car model and labor costs. A Mass Air Flow Sensor costs $100 and $400 and you can expect the labor costs to be $40 to $150.

The MAF sensor is often quite expensive, as you sometimes have to replace the whole MAF sensor housing also, but even just the sensor itself can be quite expensive.

Fortunately, it is often very easy to replace the MAF sensor and is done in 10 minutes for most car models. You can often do this yourself if you only have basic car knowledge.

MAF Sensor FAQs

What happens when the MAF sensor goes bad?

The MAF sensor is a vital part of the car engine, and therefore a lot of things can happen to your car engine when it gets bad. The most common things that happen are a control lamp, poor engine performance, uneven idling, and changed fuel consumption.

How do you test a MAF sensor?

To test a MAF sensor, you need a multimeter to measure the resistance in the sensor. To know which resistance you should see on the multimeter, you can look it up in your repair manual for your car model.

Can you drive with a bad mass air flow sensor?

A bad air mass sensor can cause many problems with your car engine, and therefore it is not recommended to drive with it. However, if your engine is running well, you can drive slowly to the nearest workshop.

How often does a mass air flow sensor need to be replaced?

There is no service schedule for when to replace the MAF sensor. The MAF sensor is made to last the life of the vehicle, so it should only be replaced if it is faulty. However, you can clean the MAF sensor every 100,000 miles to keep it functional.

(Video) Mass Air flow sensor faulty solutions/ What are the caused and tips for failed MAF sensor andam

FAQs

How much does it cost to replace a MAF? ›

Replacing the mass airflow sensor should cost $300 or less for parts and labor for most civilian cars, trucks, and SUVs.

What happens if you don't replace MAF sensor? ›

A bad MAF sensor can cause your vehicle to experience poor drivability issues such as engine stalling, jerking or hesitation during acceleration. This could happen while speeding up on the highway on-ramp or cruising down a city street. These issues can create dangerous situations causing accidents and injury.

How long does it take to replace a mass air flow sensor? ›

Less than one hour. Disconnect the negative battery terminal. Unplug the electrical connector on the mass air flow sensor. Use a flathead screwdriver to unfasten the air intake hose clamp at the throttle body.

What are 2 symptoms of a dirty MAF sensor? ›

Seven Signs Your Mass Airflow Sensor Is Dirty Or Going Bad
  • Black Exhaust. One sign that your vehicle's MAF is going bad is black exhaust from excess fuel. ...
  • Check Engine. A faulty mass airflow sensor is a common reason why a check engine light comes on. ...
  • Hard Starts. ...
  • Hesitation. ...
  • Poor Gas Economy. ...
  • Rough Idle. ...
  • Trouble Accelerating.
1 Apr 2021

How do I reset my mass airflow sensor? ›

Resetting the Mass Air Flow Sensor by Disconnecting the Battery
  1. Remove the old MAF sensor and replace it with a new one.
  2. Before you connect the sensor with its harness, disconnect the battery from the ground cable.
  3. Leave it like that for around 10 minutes.
  4. The whole system will be reset now.

What should I do after replacing MAF sensor? ›

What To Do After Replacing Mass Air Flow Sensor?
  1. Turn the engine off. ...
  2. Find the negative terminal of the battery. ...
  3. Use a wrench to loosen the negative terminal nut.
  4. Remove the negative connecting point.
  5. Repeat the process with the positive terminal of the battery.
  6. Disconnect the battery.
6 Feb 2022

Is it better to clean or replace a mass air flow sensor? ›

MAF sensors can become damaged, but more often they just get too dirty to do their job well. In this case, they can be cleaned but if it is a mechanical or electrical failure, they must be replaced.

Can you drive with a broken mass air flow sensor? ›

The good news is you can drive with a bad mass air flow sensor. However, a bad sensor can cause dangerous engine hiccups, so you are only allowed to handle this faulty component for a specified amount of time. In particular, defective air flow sensors can lead to driving problems.

Does cleaning MAF sensor work? ›

It is a good idea to clean the MAF sensor every time you change or clean the air filter. A clean MAF sensor can restore 4-10 horsepower to the wheels, which is a significant number for just cleaning a sensor.

Do you have to reset car after changing MAF sensor? ›

After Installation of the new MAF:

But if the motor continues to have problems, run the engine idle for 20-30 minutes. 2. You can reset the ECU by disconnecting the battery for 10 min.

Does a new MAP sensor need to be programmed? ›

Each sensor therefore needs to be Calibrated - it needs to be programmed into the ECU what the pressure reading is at a low point around 0 Volts, and at a high point around 5 Volts.

What happens when you unplug a MAF sensor? ›

Q: Car runs with the mass airflow sensor unplugged. If you plug it in it will die if the car is running. If you unplug the mass air flow sensor the car will start. If you try to plug it in while it's running the car will die.

How do I know if my mass airflow sensor is working? ›

How To Tell If Your Mass Air Flow Sensor Is Bad On Your Car - YouTube

Will a bad MAF sensor throw a code? ›

A faulty MAF sensor can also trigger other codes, such as those pertaining to an air/fuel ratio imbalance or an engine misfire.

How do you test a MAF sensor? ›

Pop the hood open. Lightly tap the MAF sensor and electrical connector with a screwdriver handle. Wiggle the wires as well. If the engine stalls, idle is upset, or idle gets better, the MAF sensor is likely defective.

How long does it take for mass air flow sensor to reset after cleaning? ›

How Long Does It Take for Mass Airflow Sensor to Reset After Cleaning? It will take about 15 to 30min to reset the sensor. You will notice errors very often when the mass airflow sensor gets bad.

Should I disconnect battery when cleaning MAF sensor? ›

You probly should disconnect the bat first befor you clean it. But the Main reason to unhook it is to reset the puter so it can relearn the clean maf.

What causes mass air flow code? ›

What causes the P0101 code? The most common source of the problem is the sensor range of the MAF sensor being outside of the normal operating range. This provides input to the Engine Control Unit (ECU) giving outputs that are beyond the programming for the engine management.

What does the mass airflow sensor affect? ›

A mass airflow sensor (MAS) determines the mass of air entering a vehicle's fuel injection engine, and passes that data to the Engine Control Unit, or ECU. The air mass information is necessary for the ECU to correctly balance and deliver the correct amount of fuel to the engine.

How much is a MAF sensor? ›

MAF Sensor Replacement Cost

The replacement cost of a mass air flow sensor can anywhere from $80 to $380. The cost of the part alone is about $30 to $300 with the lower end of the range for common aftermarket mass air flow sensors while higher quality or more complicated OEM sensors are more expensive.

How many miles does a MAF sensor last? ›

A mass air flow typically last between 80,000 miles to 150,000 miles. Proper maintenance of the mass air flow and cleaning it will help prolong its life. However, there are a few vehicle symptoms that will tell you when it is time to replace the air flow sensor.

What is the difference between MAP and MAF sensor? ›

What are some differences between a MAP and MAF sensor? While a MAF sensor is always located before the throttle body, a MAP sensor can usually be found attached to the intake manifold. Because it is in the intake tract, A MAF sensor will also have its own housing (usually plastic) to hold it in place.

What is a Karman vortex air flow sensor? ›

Karman Vortex

This sensor determines the velocity of the air flow by monitoring the frequency of an artificially induced turbulence using optical or ultrasonic sensors. The ECM combines this frequency with air temperature measurements to calculate the mass air flow.

Can a bad MAF sensor cause misfire? ›

Even a dirty MAF sensor can cause a lean code and/or misfire to occur. The engine may be stalling because it isn't getting enough throttle opening.

Can I use throttle body cleaner on MAF? ›

Yes, you can use a MAF cleaner on a throttle body, but you cannot use throttle body cleaner on a MAF.

What else can you use to clean MAF sensor? ›

Rubbing alcohol is a trendy cleaner that might come in handy. It is not only effective in dislodging dirt stuck to the sensor but also has a fast-drying time. Ideally, after cleaning your car's MAF sensor, it should be dry before starting your vehicle to avoid any complications.

Can you use rubbing alcohol to clean MAF sensor? ›

Any unintentional touch can give false readings and damage. And of course you don't need to rub off the sensors since the alcohol will remove the grim by itself. Be sure to get the isopropyl alcohol into the grannies as well as the nooks on the air flow sensor. These are the parts that need to be cleaned the most.

What does a dirty MAF sensor look like? ›

How to Clean and Diagnose a Dirty Mass Air Flow (MAF) Sensor

How do you test a MAF sensor? ›

Pop the hood open. Lightly tap the MAF sensor and electrical connector with a screwdriver handle. Wiggle the wires as well. If the engine stalls, idle is upset, or idle gets better, the MAF sensor is likely defective.

Is it better to clean or replace a mass air flow sensor? ›

MAF sensors can become damaged, but more often they just get too dirty to do their job well. In this case, they can be cleaned but if it is a mechanical or electrical failure, they must be replaced.

What happens if you unplug mass air flow sensor? ›

If you unplug the mass air flow sensor the car will start. If you try to plug it in while it's running the car will die.

Does cleaning MAF sensor work? ›

It is a good idea to clean the MAF sensor every time you change or clean the air filter. A clean MAF sensor can restore 4-10 horsepower to the wheels, which is a significant number for just cleaning a sensor.

Will a bad MAF sensor throw a code? ›

A faulty MAF sensor can also trigger other codes, such as those pertaining to an air/fuel ratio imbalance or an engine misfire.

Can a car run without a mass air flow sensor? ›

Without a proper signal from the mass air flow sensor, the powertrain control module (PCM), which manages the engine, transmission, and other systems in your car, won't know how much fuel the engine needs. This can either cause the engine to run too lean (too little fuel) or too rich (too much fuel).

What is the difference between MAP and MAF sensor? ›

What are some differences between a MAP and MAF sensor? While a MAF sensor is always located before the throttle body, a MAP sensor can usually be found attached to the intake manifold. Because it is in the intake tract, A MAF sensor will also have its own housing (usually plastic) to hold it in place.

Can a dirty MAF cause rough idle? ›

The MAF measures the rate of air flowing into fuel-injected engines. A dirty or faulty MAF will cause an engine to idle roughly, as well as stall when idling. There are DIY aftermarket solvents you can use to clean a dirty MAF.

Can I use throttle body cleaner on MAF? ›

Yes, you can use a MAF cleaner on a throttle body, but you cannot use throttle body cleaner on a MAF.

Can you use electronic cleaner on MAF sensor? ›

Electrical contact cleaner will be fine. Do not use carb cleaner or WD40!

What happens if you unplug a map sensor? ›

With the MAP sensor disconnected, the fuel delivery will be excessive and could cause harm to the engine and exhaust system (catalytic converters). Your vehicle getting on the freeway accelerating, bogging down, and reaccelerating sounds like fuel starvation. It could be a fuel pump fault or a plugged fuel filter.

What is a normal MAF reading at idle? ›

With the engine at idle, the MAF's PID value should read anywhere from 2 to 7 grams/second (g/s) at idle and rise to between 15 to 25 g/s at 2500 rpm, depending on engine size. Most manufacturers provide specifications for air flow at idle; some will provide specifications at several engine speeds.

Can MAF sensor cause misfire? ›

Even a dirty MAF sensor can cause a lean code and/or misfire to occur. The engine may be stalling because it isn't getting enough throttle opening.

Videos

1. How To Tell If Your Mass Air Flow Sensor Is Bad On Your Car
(proclaimliberty2000)
2. SYMPTOMS OF A BAD MAP SENSOR
(EasyAutoFix)
3. Accurately Diagnosing a Mass Airflow Sensor
(Justin Miller)
4. Ford P0171 P0174 P1101 - Ford Mass Airflow Sensor Diagnosis Video
(The Car Doctor)
5. HOW TO KNOW IF MAF SENSOR IS BAD. MASS AIR FLOW SENSOR TEST
(Auto Repair Guys)
6. Mass Airflow Sensor (with ChrisFix!) – 2004-2008 5.4L Ford F-150
(BlueDriver)

Top Articles

Latest Posts

Article information

Author: Rev. Porsche Oberbrunner

Last Updated: 01/20/2023

Views: 6145

Rating: 4.2 / 5 (53 voted)

Reviews: 92% of readers found this page helpful

Author information

Name: Rev. Porsche Oberbrunner

Birthday: 1994-06-25

Address: Suite 153 582 Lubowitz Walks, Port Alfredoborough, IN 72879-2838

Phone: +128413562823324

Job: IT Strategist

Hobby: Video gaming, Basketball, Web surfing, Book restoration, Jogging, Shooting, Fishing

Introduction: My name is Rev. Porsche Oberbrunner, I am a zany, graceful, talented, witty, determined, shiny, enchanting person who loves writing and wants to share my knowledge and understanding with you.