Bad MAF Sensor Symptoms and How to Check One Yourself

If you have a rough running engine or one of these other symptoms of a bad MAF sensor shown in this video, follow these steps to inspect the mass air flow sensor.

Symptoms of a Bad Mass Air Flow (MAF) Sensor

If the MAF sensor is dirty or damaged, it won’t send accurate readings to the computer.

Not replacing a damaged MAF sensor can cause problems with other parts like the catalytic converter.

Symptoms of a bad MAF sensor include:

  • Decrease in fuel economy
  • Check engine light for a related code, like P0101 to P0104
  • Problems starting the vehicle, like a no-start condition, cranking but no starting, or engine stalling
  • Engine misfire, rough running engine, or rough idle
  • Black smoke from the tailpipe from a running rich condition
  • Acceleration feels hesitant

What Is the MAF Sensor?

The MAF sensor is important for engine performance. It sends a reading to the vehicle’s computer for adjusting the amount of fuel being sent to the combustion chamber. The engine needs a certain amount of air and fuel to create combustion and move your vehicle forward. If the air/fuel ratio is off, the engine will have a running condition, like rich or lean.

How to Check a MAF Sensor

Steps to check a MAF sensor

  1. Wear Hand and Eye Protection

    Wear hand and eye protection at all times.

  2. Locate the MAF Sensor

    Generally, the MAF sensor is placed near the engine air filter housing box. This is so it can measure the amount and density of air flowing from the air filter.

  3. Check the MAF Sensor for Damage or Debris

    The MAF sensor can fail if it’s dirty or clogged, or if it’s damaged or cracked. Moisture can accumulate inside the sensor and damage it.

    Check the MAF sensor for damage like cracking or dry-rotting. Disconnect the electrical connector and check the terminals for discoloration, which is a sign of damage and corrosion. Corrosion will cause resistance, so the connector will need to be cleaned or replaced.

    Remove the screws from the MAF sensor and carefully pull the MAF sensor up and out. Check for a metal piece along the sensor, which is a delicate sensing agent. Make sure the area is clean of debris.

  4. Replace or Clean the MAF Sensor

    If the sensing agent area is dirty, you can try to clean the MAF sensor with MAF sensor cleaner, or you can replace the MAF sensor.

    Pro Tip: Some manufacturers only recommend replacing the MAF sensor

    How-to video: Replacing a MAF sensor on a 2009 to 2012 Chevy Suburban

    To clean the sensor, wear hand and eye protection and spray away from your face. Spray the area with MAF sensor cleaner, and then spray it with compressed air from a distance to reduce pressure on the sensor and dry off the cleaner. Then inspect the sensor and see if it’s in better condition.

    More on how to tell if the problem is a MAF sensor or a dirty engine air filter

    More on checking a MAF sensor

More Common/Causes of a Rough Running Engine

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Bad MAF Sensor Symptoms - DIY Diagnose & Fix - 1A Auto
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Bad MAF Sensor Symptoms - DIY Diagnose & Fix - 1A Auto
Learn how to tell if your car is experiencing bad MAF sensor symptoms with these expert tips. Find out how to diagnose and replace a bad mass air flow sensor in your car or truck easily yourself
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1A Auto
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