How To Clean The Ford Mass Air Flow Sensor

One of the most common problems, with MAF sensor equipped Ford (Mercury and Lincoln) vehicles, is that the MAF sensor's hot wires will get dirty (contaminated).

This contamination will rob you of gas mileage and performance. Not only that, in some cases this condition will light up your check engine light with a P0171 or P0174 (lean A/F mixture) code.

Well, this article will help you to clean your mass airflow sensor in a step by step fashion.

You can find this tutorial in Spanish here: Cómo Limpiar el Sensor de Flujo de Aire (MAF) de Ford (at:

Important Suggestions And Tips

Tip 1: The safest way to clean the MAF sensor's hot wires, is to just spray them and let them air dry. Avoid physically touching them, like with a cotton swab, since this could break the hot wires.

Tip 2: Do not use carburetor spray cleaner or brake cleaner. Both of these are very harsh solvents and can damage the inner circuitry of the MAF sensor and now you'll have a BAD MAF sensor on your hands (this I can vouch for from personal experience)

Tip 3: Do not use gasoline. Gasoline will leave a petroleum residue on the hot wires and this residue will attract more dirt (like a magnet to metal)... not to mention that gasoline is just too dangerous to use as a cleaner.

How To Clean The Ford Mass Air Flow Sensor

Tip 4: Your local auto parts (like AutoZone or O'reilly Auto Parts) will have the appropriate MAF sensor cleaner. The most common/popular is the CRC Mass Air Sensor Cleaner (part number: 05110).

I've always thought the CRC MAF sensor cleaner a tad too expensive (but it beats using something unapproved and frying the MAF sensor) and so on occasion, I have also used a regular electronics spray cleaner from my local Radio Shack or Fry's electronics store with the same success.

Symptoms Of A Dirty Ford MAF Sensor

The most common symptom of a dirty mass air flow (MAF) sensor is a lack of power.

Unfortunately, the PCM (Powertrain Control Module = Fuel Injection Computer) is not smart enough to sense a dirty MAF sensor and so you're not gonna' get a dirty MAF sensor diagnostic trouble code lighting the check engine light.

A dirty MAF sensor will cause one or all of the following symptoms:

  1. The engine idles fine, but when you accelerate the vehicle (not just the engine) is when you feel the lack of power.
  2. Engine running lean which causes the PCM to set one or both of the following diagnostic trouble codes:
    1. P0171: System Too Lean Bank 1.
    2. P0174: System Too Lean Bank 2.
  3. Fails the state mandated yearly emissions test.
  4. BAD gas mileage.

The PCM uses the MAF signal to know how much air is entering the engine. In knowing the exact amount of air entering the engine, the PCM can now calculate the correct amount of fuel to inject into every cylinder.

When the mass air flow sensor on your Ford car (pick up, van, mini-van or SUV) starts to get dirty, the dirt (technically called: contamination) starts to interfere with the way the MAF sensor measures the incoming air.

Thus a dirty (contaminated) MAF sensor still creates a signal but it's a MAF signal that is not conveying the correct amount of air that's entering the engine. And so the PCM does not inject the correct amount of fuel for the true amount of air entering the engine.

As I mentioned before, the PCM can't tell you that the MAF sensor is dirty, since a dirty MAF sensor DTC does not exist and as easy as it is the check to see if it's dirty or not, there's really no need for one.

OK, let's turn the page and get this show on the road...