The Mass Air Flow sensor (or MAF sensor)in your Mercedes is responsible for determining the amount of air that enters your vehicle’s engine and then providing the onboard computer, or Engine Control Unit/ECU, with this data reading. The ECU is then able to use this data to provide the engine with the correct amount of fuel needed to achieve the optimal air-to-fuel ratio needed for successful ignition. When the MAF sensor fails, a range of issues can be experienced by your Mercedes, notably affecting the overall performance of your car.

How does it work?

The MAF sensor is located between your Mercedes’ throttle body and air filter. Modern vehicles use a hot wire sensor which entails the use of one hot wire and one ambient temperature wire. The MAF sensor relies on a microprocessor to help it to measure the air entering the engine. It is able to provide the mass of air entering accurately by measuring how much energy is required to keep the hot wire at a steady 200F above the ambient temperature of the air. It can then collate this data and pass it on to the onboard computer.

Signs and Symptoms of a Faulty MAF Sensor

MAF sensor failure comes with similar symptoms to those of low compression or low vacuum problems as well as those which can be experienced with low fuel pressure or a faulty fuel pump, making it tricky to pin-point. However, the most common symptoms are listed below:

  • engine struggles to start correctly or to turn over
  • engine stalls often, most commonly shortly after starting
  • noticeable engine hesitation or drag most keenly felt when idle or under loads
  • engine hiccups
  • engine runs excessively rich or excessively lean

If you are not in the know when it comes to auto repair and are experiencing the issues listed above, then you should bring your car to a Mercedes specialist for proper diagnosis, servicing, replacement, or repair. A faulty MAF sensor will usually generate a specific error code that a mechanic can read using diagnostic equipment, meaning getting to the root of the problem is usually far quicker and safer than poking around the engine at home.

Cleaning your MAF Sensor

While repair and replacement when things go wrong is best left to the professionals, you can take charge of maintaining your MAF sensor by cleaning it. In general, it is recommended that you do this every 6 months or around the time you change out your engine oil. Doing both at once can save you a good deal of time and money.

Step 1: Remove the Sensor

To properly clean your MAF sensor, you need to remove it. To do this, you need to open your Mercedes’ air box. This will require the use of a flat head screwdriver. When you remove the sensor, you must make sure to avoid touching the wires. While you won’t get an electric shock from them, the wires used in the system are very delicate and can easily be broken, which can set you back $100 to replace.

Step 2: Clean the Sensor

There are two ways you can clean your sensor. First, you can place it in a bag of rubbing alcohol and provide gentle agitation. Second, you can purchase specialized mass air flow sensor spray cleaner from an auto repair shop and gently spray you sensor. This is the more expensive option but may be worth trying if this is your first time cleaning your sensor.

Step 3: Dry and Reinstall the Sensor

Let your new, clean MAF sensor sit before replacing it, usually for at least 20 minutes if not more, as it needs to be completely dry before it is reinstalled to prevent damage. You could get on with your oil change in the meantime. When the MAF sensor is dry, simply reverse the steps you took to remove it, and your work is done.


Dells Service Center

When it comes to complete peace of mind involving the health of your vehicle, you should always bring your Mercedes to a specialist auto repair center for a full check up. Residents of Green Bay, Manitowoc, and Sturgeon Bay, WI, should look no further than Dells Service Center for reliable repairs that you can trust. Call us today or come by to speak to a specialist.

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