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A removed mass airflow sensor
You MAF to be kidding me

VW's History of Bad Mass Airflow and O2 Sensors

A mass air flow sensor, or MAF, monitors the amount and density of air entering the engine. I’m guessing you could figure that out from the name, but not many know that its an integral component in most modern engines.

It is usually installed inside the intake air duct, between the air filter and the engine.

The MAF sends its measurements to an engine control unit (ECU), which then uses that data to calculate when to deliver fuel, how much, and when to generate a spark. The MAF is sometimes used in conjunction with an O2 sensor that provides a “closed-loop” feedback in order to make corrections to that predicted air mass.

What Causes the MAF to Fail

Engines need a proper blend of air, fuel, and combustion to run efficiently. So a properly functioning MAF is crucial to a smooth ride.

VWs with MAF Complaints
Make Model Years
Volkswagen Beetle 2001
  GLI 2000 /  2013
  Jetta 2000 /  2004 /  2012 /  2013
  Passat 2000 /  2001 /  2007

Like anything mechanical or electrical, a MAF tends to wear down over the years. And while MAF problems aren’t specific to Volkswagen, it does feel that their tend to just wear down a lot faster.

Of course, any MAF will start failing if it gets too dirty to do its job. If an owner doesn’t regularly replace their air filter (or replaces it with a cheapo-version) it can cause a buildup of air impurities on the MAF.

What Happens When the Sensors Start Failing?

  • The engine is hard to start
  • The engine stalls or misfires
  • Poor acceleration characterized by hesitation or “jerking.”
  • Poor idle performance
  • A negative effect on fuel economy
  • A constant, headache-inducing, retina-burning warning light that will haunt your dreams (is it obvious I’ve had this problem before?)

Cleaning or Replacing the MAF

While you can clean a dirty MAF, in many instances its easier to just replace the unit.

A MAF at a dealership can cost anywhere between $75—$150 dollars, with labor costs adding another $150 to that total. You can try and clean the mass air flow sensor yourself by following the instructions in this article:

OK, Now What?

Maybe you've experienced this problem. Maybe you're concerned you will soon. Whatever the reason, you can help make sure it gets the attention it deserves.

On the Record

“I thought I might be able to get away with driving around with the faulty part, but found out a malfunctioning MAF can lead to stalling, misfiring, poor fuel economy or bad acceleration. $100 for the part and $75 for the labor later I was on my way. Until a few days later when the MAF sensor malfunctioned again.”

2004 Jetta Owner in Williston, VT

“I've never had a problem with this in other makes of cars, but for my VW Passat, it seems like I need to replace it every 3 years. VW extended the warranty to 7 years for Mass Airflow to 7 years for new cars, but for existing VW owners, there is nothing we can do about it except replace it.”

2001 Passat Owner in Media, PA

“The code for MAF sensor is on all the time, and you can tell it's really affecting the performance of the car. It drives weird at high speeds, feels like I'm constantly going over small bumps. Gas mileage isn't as great, either. I've seen videos and sites claiming just to clean it, but I'm afraid it won't work.”

2004 Jetta Owner in Clarksville, IN