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What Causes a Mass Air Flow Sensor to Go Bad?

Mass air flow sensors are a bane for car owners. When your check engine  light comes on, there’s a good chance that it’s alerting you to some form of an air flow issue in your vehicle. The vehicle’s air flow is very important and will take significant amounts of air into the vehicle to keep the vehicle running properly.

But a lot of owners do not know how to correct the issue or why sensors go bad in the first place.

You can also clean a mass air flow sensor which may help it work better or start working properly again.

What’s the Purpose of a Mass Air Flow Sensor?

Your vehicle has a lot of sensors, and this sensor is meant to provide just the right amount of air for the fuel injection system. Sensors monitor the amount of air that enters the system and makes its way to the Engine Control Unit.

The right balance is very precise, and poor engine performance will be one of the main issues when these sensors no longer work properly.

Signs that your sensor may not be functioning properly, aside from popping up on FIXD or Uberfix MD, are:

  • The engine is struggling to turn over
  • The vehicle is having issues starting
  • The vehicle stalls shortly after starting
  • Under load or when idle, the engine hesitates
  • During acceleration, the vehicle will hesitate or even drag
  • The engine “hiccups”

A complete diagnostic check will be needed to be able to determine exactly what’s wrong with the vehicle. A mechanic will be able to check the engine’s code to determine if the sensor is bad or not.

You can also use a code reader or scanner to be able to determine if the sensor is bad on your own.

Why Mass Air Flow Sensors Fail

Sensors are in use every time your vehicle is operating. A lot of manufacturers have repeated issues with sensors, so this is common. You’ll find that these issues plague BMW, Mercedes, Ford, Toyota, Honda – every manufacturer has problems.

The sensor can be:

  • Contaminated
  • Damaged

If you did not install the air filter properly, it can lead to the immature failing of the sensor. There are also many owners which will allow for air filters to be cleaned by soaking it. When these filters are reinstalled, the extra dampness can lead to sensor damage.

There’s also the risk of debris getting stuck in the sensor which can lead to failure.

The good news is that while the sensors are expensive, they’re also easy to fix. Depending on the vehicle, the sensor can be $100 to $400 to purchase. You’ll also want to take this time to replace your air filter and ensure that it’s properly installed.

You do not want to have to replace the sensor again because the filter wasn’t properly installed.

Sensors will also take in a lot of pollution, and if the sensor is dirty, you should try to clean it before replacing it. A lot of mechanics will recommend that you try to clean the sensor so that it starts working again. Cleaning may only be a temporary solution, but it depends if the sensor has another fault that you’ve yet to discover.

How to Clean a Mass Air Flow Sensor

If you want to clean the sensor, you can definitely clean it on your own. A lot of people never clean their sensor, but some mechanics recommend cleaning the sensor each time you change the air filter or every six months.

It’s up to you whether or not to clean the sensor, but it can only help your vehicle run better for longer.

You’ll want to gather a few items before getting started:

  • Rubbing alcohol
  • Plastic bag

I am going to tell you the homemade solution for cleaning your sensor. If you go to your local auto parts store, you’ll find that there are commercial cleaners that can be used that will work just as well.

These commercial cleaners are more expensive than the at-home method, and you’ll need to get to the store, too.

Once you have gathered all of your supplies, you’ll want to remove your vehicle’s sensor. You can watch YouTube to figure this out, but it’s really easy once you locate the vehicle’s air box. Once located, open up the box and then you’ll want to use a screwdriver to get the sensor out of the box.

Do not touch any wires at this time.

The wires are very delicate, so touching them can lead to the wire breaking, which is a very costly repair. You may have to pay up to $100 just to replace these wires, so be very careful.

Everything is disconnected, and now it’s time to commence with the cleaning.

You can fill the plastic bag with alcohol, place the sensor inside of the bag and gently swish the alcohol around. The goal is to have the rubbing alcohol remove all of the dirt and debris off of the sensor.

Continue moving the bag around until the sensor is completely free of any dirt and grime.

It’s time to remove the sensor from the bag and allow it to dry properly. I recommend placing the sensor on a clean cloth that is free from any loose fabric. You need to allow the sensor to fully dry. A lot of people recommend 20 minutes of drying, but it usually takes me a lot longer until the sensor is completely dry.

I recommend performing your cleaning on a night when you have the next day off of work.

You’ll be allowed to let the sensor air dry for the entire night before reinstalling.

If the sensor is still wet when installed, it may become damaged and will need a full replacement. Reinstallation can be performed in the same manner as removing the sensor initially.

Mass air flow sensors will reach a point where they’re no longer a viable option to clean. Replacing the sensor is the only option at this point. The sensor may also last the lifetime of the vehicle, which is a best-case scenario.

November 12, 2019


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