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How to Inspect and Clean a Mass Air Flow Sensor (MAF)

313K views 70 replies 46 participants last post by  Chevy7  
#1 Ā· (Edited by Moderator)
Cleaning a MAF is one of the easiest things you can do to keep your vehicle idling and running smoothly. Generally, this is a novice level activity. The only thing that could make it difficult is if your particular MAF is located in a hard to reach area. I have always done this at a frequency of every other oil change, or every 10,000 to 12,000 miles.

What is a MAF?
The Mass Air Flow sensor is used to measure the amount of air entering the engine. This measurement is used by the engine computer or ECM to calculate proper amount of fuel injected into the cylinders in order to provide optimum combustion and low emissions.
Problems with Mass Air Flow sensors are common. Bad or contaminated Mass Air Flow sensor can possibly cause a wide range of various vehicle driveability problems such as stalling, especially when the engine is cold, misfiring, poor acceleration, etc.
In addition, a problem with the Mass Air Flow sensor often causes the "check engine" or "service engine soon" light in the vehicle instrument panel to illuminate.

How to Clean a MAF:
1. Buy a quality MAF cleaner. DO NOT use carb or throttle body cleaner, or any other solvents. As you will see, the MAF is a very sensitive part. Use only the approved solvent, and follow the directions on the can carefully.
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2. Open the hood of the vehicle.
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3. Locate the air filter housing. Usually, the MAF will be just "downstream" of the air filter, in the tube that carries air to the resonator and throttle body. You can see the MAF and it's related connector circled in this photo:
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4. Release the electrical connection on the MAF. There is a small tab that holds the connection in place.
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5. Using either a phillips screwdriver or a torx bit (my truck uses a T-10 torx), unscrew the screws holding the MAF in place.
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6. Make sure you know what direction the MAF is in place. Often, you will see an airflow arrow to help you. Make sure you are able to put the MAF back in the same direction later!
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7. Carefully remove the MAF. Note the thin wires that run across the MAF. When this unit is in operation, those wires get hot. Simply stated, the rate (resistance) at which the wires heat or cool gives the computer the inofrmation about how much air is moving across them, and into the engine. When they are dirty, your ECM cannot correctly determine the airflow.
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8. Set the MAF on a paper towel or clean shop rag. Follow the directions on the can to spray the solvent on the MAF. Be careful that the spray tube or other things do not bump the MAF. Again, the wires are fragile. Spray the MAF from all sides, and then allow it to dry. Make sure the MAF is fully dry before reassembling.
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9. Reassemble the MAF. Ensure you install it in the correct direction. Also ensure the wire harness is re-connected.

10. It is not required, but I also ensure that I disconnect the battery while I complete this procedure. Doing so will reset your ECM, and will take into account this cleaned MAF!

You did it! Congratulations!
 

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#27 Ā·
Big thanks guys! I found this site a couple days ago and here I am using the info I got here to get the truck running well again! I don't think the sensor has ever been cleaned in my 05 with 97k. Made a big difference! Idle used to bounce around 8-900 and it had a hesitation passing at highway speeds. No more! I went ahead and cleaned the throttle body as well, it was really really nasty and tossed in a new air filter as well! O2 sensor got replaced, no more check engine light! Hopefully I see a nice improvement in mpg......
 
#28 Ā·
Bought a can of SensorKleen, and when I looked at my sensor. Guess I'll have to remove it from the intake. Got the engine side air hose off, but the filter side doesn't move. I'll have to wait till it's not -20 C to tackle it.
Found a video for removal and installation that helped, thought I would share it with you.
Thanks for the write up!
 

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#29 Ā·
Those intake tubes are a royal pain to separate. The seem to fuse or stick together with age.
 
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#31 Ā·
starspangled6.0 said:
Great article, Eric. I've never done that before, and I'm guessing my truck hasn't had it done in a while... well, I'll add it to my to-do list!
This sounds like another "to do" item I need to add to my "servicing my truck" that I have been writing up this week.. to do this weekend. In fact, I can almost guarantee myself that my M.A.F. sensor is dirty because my truck, she's got 114k on her now.. and I know for sure that the M.A.F. sensor has never been cleaned. I always clean the throttle body thoroughly at every oil change, so it gets cleaned ever 4k miles.

But anyhow, as usual.. many thanks for the 'How To' article my friend! Grazie!
 
#32 Ā·
It was pretty nice out today so while I was out picked up a can of MAF cleaner. Got home took the MAF off it did not look that dirty until I started to spray it. I have the style with the screen in front and it was very dirty. Did not get a chance to drive after I was finished, will have to test drive it tomorrow to see if it made a difference.
 
#37 Ā·
The process should be the same regardless of year.

As far as drying time: The solvent evaporates quickly. 5 minutes is plenty.
 
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#39 Ā·
Yes. The MAF will be cool within 2 minutes of shutting off the truck. No worries.
 
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#40 Ā·
Cool I already did it. I can tell a difference. Maybe placebo effect but ill take it. My k&n cai i don't think was on properly and on of the clamps was not tight. So maybe that's the difference I'm noticing.
 
#41 Ā·
If you're K&N was recently recharged or a little heavy on oil from the factory it could have fouled your MAF, definitely would have noticed a difference then.
 
#43 Ā·
I have an 03' 2500. About cleaning the MAF, are just the wires sprayed or the whole plastic housing? (I have not bought the can to read yet). A little project for tomorrow. Thanks in advance.
 
#44 Ā·
Just the wires. It won't hurt if you hit the housing, but it does not help either. Its the wires that matter.
Remember, less is more. Its a fragile component.

- EKinMN via AutoGuide.com App
 
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#45 Ā·
I wanted to see what y'all thought about this, been having a engine code come on and off a lot here lately. I think it's my MAF. I took it out, clean it and my TB. Drove for a few hours and it came back on...

I think it's my MAF, if you look closely at my pic, the wire that's supposed to lay flat on top is slightly leaning. My TB was junked up on the engine side. I haven't been able to figure out my problem though.
 

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#46 Ā·
I am not seeing what you are seeing. You see a bent or leaning wire?
 
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#47 Ā·
Yes, if you look closely at my picture, you can see the top wire leans a little bit to the right. (May have to enlarge my photo to see) the new one in the bottom picture is not leaning, it lays flat across the 2 pillars. I am beginning to believe now though that it's 1 or 2 of my o2 sensors that is throwing the code. P0171 and P0174 are the 2 codes I pulled from the obd yesterday, so it's gotta be either that or a vac line I'm guessing.
 
#50 Ā·
Great How To and Pics spent the afternoon cleaning MAF with given instructions (also TB). Ended up with more, better response from the pedal. :D
 
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