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Mercedes MAF Sensor Replacement
 
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Pelican Technical Article:

Mercedes MAF Sensor Replacement

Steve Vernon

Time:

1 hour1 hr

Tab:

$400

Talent:

*

Tools:

T20 Torx security bit, flat head screw driver

Applicable Models:

Mercedes-Benz ML320 (1998-03)
Mercedes-Benz W203 (2001-07)

Parts Required:

New MAF

Hot Tip:

Do not use oiled filters

Performance Gain:

Better mileage

Complementary Modification:

Replace air filter

The mass air flow sensor (MAF) is used to measure the amount and temperature of air that is entering the engine at any one time. The mass air flow sensor senses the total amount of air passing the sensor and allows the fuel injection system to adjust the fuel mixture to compensate for cold weather and/or high altitude conditions. The MAF also incorporates an internal intake air temperature sensor which measures the temperature of the intake air.

The first indicator that you might have a problem with the MAF is the presence of a check engine light (CEL) on your dashboard. The check engine lamp can be caused by a wide variety of problems with the engine: you need to read the codes from the computer to get a starting clue as to what the problem is. However, the engine will not be operating at peak efficiency, and you will most likely experience a loss in power and a decrease in gas mileage as a result. It's best to get the problem taken care of relatively quickly, as running the engine in this condition can potentially cause damage to other components like the catalytic converters.

Vacuum leaks and other air leaks in the system can cause MAF sensor errors. If you have a crack or leak in your air intake downstream of the sensor, then the MAF will be sensing less air than the engine is actually receiving. You should carefully inspect all of your hoses, clamps and intake tubes for air leaks prior to replacing the sensor.

You will need to remove the engine covers and air intake ducts to perform this work. Please see our article on replacing your air filters.

The new MAF comes complete in the air body housing so you will have to remove the complete housing to replace it. This article also shows you how to remove the sensor from the housing to clean it. Make sure you only clean it with MAF sensor cleaner and that you never touch the sensor face with anything or you will destroy it.

With the air filter covers off you can see the MAF sensor housing at the rear of the engine (red arrow) along with the harness (yellow arrow).
Figure 1

With the air filter covers off you can see the MAF sensor housing at the rear of the engine (red arrow) along with the harness (yellow arrow).

Disconnect the harness (red arrow) by squeezing the two clips together and pulling it from the housing.
Figure 2

Disconnect the harness (red arrow) by squeezing the two clips together and pulling it from the housing.

Use a flat head screw driver and release the clip (red arrow) that holds the sensor housing to the intake manifold (yellow arrows).
Figure 3

Use a flat head screw driver and release the clip (red arrow) that holds the sensor housing to the intake manifold (yellow arrows).

Slip the mount off the housing.
Figure 4

Slip the mount off the housing. Here you can see the center clip (red arrow) and the clips that hold it to the manifold (yellow arrows).

Wiggle the housing off the end of the throttle body.
Figure 5

Wiggle the housing off the end of the throttle body. You will have to disconnect the breather tube (red arrow) to remove it from the engine.

This photo illustrates the two clips (red arrows) that hold the housing to the throttle body.
Figure 6

This photo illustrates the two clips (red arrows) that hold the housing to the throttle body.

There is a small clip (red arrow) on the rear of the housing that you need to slide back so you can pull the MAF sensor housing from the other housing.
Figure 7

There is a small clip (red arrow) on the rear of the housing that you need to slide back so you can pull the MAF sensor housing from the other housing.

There are two T20 Torx security screws (red arrows) that hold the MAF sensor in the housing.
Figure 8

There are two T20 Torx security screws (red arrows) that hold the MAF sensor in the housing. You can remove these with the housing in or out of the car.

Only clean the sensor with MAF sensor cleaner and never touch the sensor film (red arrow) with anything.
Figure 9

Only clean the sensor with MAF sensor cleaner and never touch the sensor film (red arrow) with anything.

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Comments and Suggestions:
patrick Comments: Hi there,i got w203 c240 with high rough idle and i've changed airmass sensor also throttle velve but still idling rough,even if i unplug the airmass sensor cable
December 4, 2016
Caheh Comments: Hi, guys i have a c280 W203 2007, and when the check engine ligth on the codes that appear are P2188, P2190.

can you help me with this codes? because I am breaking my head with this trouble.

thanks best regards
November 26, 2016
  Followup from the Pelican Staff: Check the intake air ducts as well as the seal at the throttle housing. They can set this fault if leaking. - Nick at Pelican Parts  
barbc Comments: I have a 2006 Mercedes Ml350 I just had the intake manifold replaced because of a whole in it which cost me 1500.00 Now the engine light keeps going on and off and they have said that I need new air mass sensors. One mechanic said this should have been done or at least checked when they replaced the intake manifold. What is your opinion.
November 18, 2016
  Followup from the Pelican Staff: I don't have one without knowing the fault code that is stored. What is it? - Nick at Pelican Parts  
afner Comments: hi Nick and thanks for helpful advice,yes engine light is always on when we diagnosed it was o2 sensor and haven't changed.So how do i fix the compression pls advice
November 16, 2016
  Followup from the Pelican Staff: Did you test the compression and found it faulty? - Nick at Pelican Parts  
afner Comments: hi there, i got w203 c24 with rough idling even after i have changed airmass and throttle sensAlso can i replace 3.47 ratio diff by using 3.46
November 16, 2016
  Followup from the Pelican Staff: Is the check engine light on or flashing when the problem is present? Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
Nna Comments: I have 2001 C240,it always Miss fire, each time I change the air flow meter it will be OK but after some days it gets bad again.. Old what could be the problem..
October 29, 2016
  Followup from the Pelican Staff:

Is the check engine light on or flashing when the problem is present? Sounds like an engine misfire. compression on all cylinders.
- Nick at Pelican Parts
 
Mawande Comments: Mercedes benz C 180 AUTOMATIC 2005 MODEL W203
October 16, 2016
  Followup from the Pelican Staff: Thanks. - Nick at Pelican Parts  
Mawande Comments: I have just bought a Mercedes BenzC180 Kompressor, automatic gearbox has been recently replaced. It drove for one day only, takes too much fuel because it changes gears very late.What could be the problem?
October 16, 2016
  Followup from the Pelican Staff: This could be a slip caused by low fluid or low pressure. Start by checking your fluid level. If it is OK, you may have worn parts causing a pressure drop and slip. I would have it checked by a transmission specialist before it gets much worse.
- Nick at Pelican Parts
 
Johno Comments: I Have a 2000 W203 C 200 Kompressor i go to take off from lights & there is a hesitation nearly a stall but then starts to run perfect, i have changed the plugs air filter & fuel filter this does dot happen all the time it can happen once a week or sometimes more frequently.I have not lost any power or suffered high fuel useage.
September 24, 2016
  Followup from the Pelican Staff: Is the check engine light on or flashing when the problem is present? Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
MartinR Comments: hi i have c200 kompressorr 2002 my car is losing power, i checked the car diagnostics and it is coming up that the air flow meter has a problem, ive changed that and restarted it, after driving it for 5kms the engine light turned on again, and the car still runs the same as before.
What else could the problem be?
September 7, 2016
  Followup from the Pelican Staff: An unmetered air leak. - Nick at Pelican Parts  
IZAD14 Comments: My C200 KOMPRESSOR 2005 has a shivering problem when I put the car into Drive and stop at traffic signals. Basically the cars RPM goes up and down between 800 to 1100 RPM when stationary on gear or slow traffic.However the RPM is stable in Neutral and car does not shake.Also noticed that this problem becomes more prominent during summer temperatures reaching 45 degrees plus. could it be the Air mass Sensor? Appreciate your input.
September 5, 2016
  Followup from the Pelican Staff: Could be a small vacuum leak, when the brake is applied, more load so causing issue only then. - Nick at Pelican Parts  
IZAD14 Comments: I have a Mercedes 2005 C200 Kompressor .Lately when driving and only when the car is stationary in traffic or moving slowly in traffic while in DRIVE the RPM is shaky and moves up and down giving the feeling of the car vibrating or shaking. The RPM goes to around 1200 then falls to 800 then up again. The car drives smooth once I accelerate or the RMP is stable at 900 if I push the gear to Neutral. Appreciate your input Thanks.
September 4, 2016
  Followup from the Pelican Staff: Could be a small vacuum leak, when the brake is applied, more load so causing issue only then. - Nick at Pelican Parts  
Steve Comments: Hi,I have e class 220 2001 my car was losing power i changed the air flow sensor and the car was driving much better but sometimes the car misfires especially when i switch on the aircon and i see also black smoke at the exhaust this car was just serviced two weeks ago what could be the problem.
August 18, 2016
  Followup from the Pelican Staff: Is the check engine light on or flashing when the problem is present? Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
Toma Comments: Every morning, my car exhaust stutters and coughs. The engine noise also rumbles fairly louder than normal. This normally happens for 3 min or so before it normalizes. The CAT converters were recently removed as they were clogged. I've also recently replaced upstream oxygen sensor based on star diagnostic readings. However, despite or because of this the exhaust stutter and cough still persists. There's also a persistent error that keeps popping up ..something about 'self adaptation...error' Any leads on what this could be?
August 3, 2016
  Followup from the Pelican Staff: What is the P-code number? I may be able to offer advice after knowing the code number and description. - Nick at Pelican Parts  
Mohammad jamal Comments: Hello i have mercedes w203 200l and i have these fault code P207E and P2086.Need Help plz
July 27, 2016
  Followup from the Pelican Staff: These could be fuel trim fault codes or catalytic converter fault codes. Check your fuel trim, if it is not skewed, the cats may be faulty. - Nick at Pelican Parts  
Shirzai Comments: 104, R/P lock Y66/1 code what is it and how to solve it
July 19, 2016
  Followup from the Pelican Staff: Need more info on the vehicle, fault code and description of problem. - Nick at Pelican Parts  
George Comments: Hello. I have a w203 diesel from 2001 and my problem is that my engine enters in limp mode from time to time, not allowing me to pass 3000rpm. The funny thing is there are no faults stored in the ECU. And also when the limp mode occurs if I stop the engine and than restart it, the car runs without any proplems afterwords. The fault mostly occurs in the morning or when it am drivin in a rainy day. Any idea what can it be?
July 15, 2016
  Followup from the Pelican Staff: Hard to say without a fault code. Maybe your scan tool can't read a pending code, that may be set causing limp mode. Try and advanced scan tool. - Nick at Pelican Parts  
Shirzai Comments: Hi, i have c 180 202 model 1996 , once i checked it show error cod p 104 , can u help me what does it mean ? And when i drove my car more and it became warm so it loss its power ?
July 9, 2016
  Followup from the Pelican Staff: That is a fault code for the mass air flow sensor. It could be faulty or a possible intake duct air leak. Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
sam Comments: I have a C180 2002, key stopped turning, hence changed the key barrel. when checked with obd2, codes came as P0172 and P0410. Can you help? Thanks
June 29, 2016
  Followup from the Pelican Staff: The codes are for secondary air and a fuel trim fault. Check fuel control and fuel trim, to see when the vehicle is broken. Also check secondary air function. - Nick at Pelican Parts  
Ollie Comments: First time i checked the code on my 2000 ml320, it was p0203. I cleared it, and now theres a p0303 which caused rough idling right after the engine light came on. When i drove it later during the day, it ran like it was normal. How can i narrow down whats wrong with cylinder 3.
May 21, 2016
  Followup from the Pelican Staff: I would check spark, fuel and compression on cyl 3. One of those will be faulty. - Nick at Pelican Parts  
huff766 Comments: My 2001 c240 idles high when I start the car or when it's running and in park position, once I put it in drive or reverse the idle goes down.
May 15, 2016
  Followup from the Pelican Staff: Check the engine for vacuum leaks. - Nick at Pelican Parts  
Zubes Comments: Thanks for the wonderful section, it has really been of help to me. But I have a non regular issue to complain about my w203 have high fuel consumption fault. At the moment there is no fault code coming up and the sound of the engine is not bad at all. I have done lots of teoubleshooting also I have replaced the entire back exhaust even when I knew that was not the fault of the car. The engine type here is Kompresor and its four cylinder. The fuel consumption is really one the high side and I have spent a fortune buying feul. Please I need help.
April 7, 2016
  Followup from the Pelican Staff: I would check fuel pressure. You could have too high fuel pressure or a leaking injector. - Nick at Pelican Parts  
Ero Comments: My Mercedes benz c180 w203 engine light came on and started jerking. The car shakes as and less power. It has 300 000 km. I serviced it 10 000 km ago. Can this be service needed or what could be the problem?
April 4, 2016
  Followup from the Pelican Staff: It's possible. Is the check engine light on? Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
izzi Comments: I ran a OBD test on my W203 200 Kompressor. It returned with the fault code P0101 "Mass or Volume Air Flow Circuit Range/Performanse Problem". Would replacing the MAF sensor fix the problem?
March 27, 2016
  Followup from the Pelican Staff: Most likely, yes. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
ZED Comments: Hi, would the MAF on Diesel W203 2003 differ from Petrol ones?
Thanks in advance!
March 14, 2016
  Followup from the Pelican Staff: Good question. I wouldn't think so. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
Jason Comments: I need to replace MAF yet I have C250. Would MAF C300 part fit for the replacement? Please recommend which I would need to purchase for this. Thanks
February 23, 2016
  Followup from the Pelican Staff: I don't believe so. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
John Comments: I have a 2002 C230 Sports Sedan. The engine starts and runs rough, has absolutely no power. Cleaned mass airflow sensor, replaced old battery but still no power. It will move but extremely slow and no acceleration. Please help!
January 20, 2016
  Followup from the Pelican Staff: Check the fuel delivery system and exhaust back pressure. - Nick at Pelican Parts  
shane Comments: Hi, my Mercedes ml 320 went for service and when I started it up it was fine as I drove it and came to a stop at the lights it started to idle rough and cut out, u started it UK again and it was OK until I stopped and the idle was low, any idea if issues gee valve is fine may be the maf?? Please advise.
October 16, 2015
  Followup from the Pelican Staff: Could be an issue with the fuel pump. I would perform a fuel delivery system test. Check fuel pressure, volume and quality. - Nick at Pelican Parts  
Rob612000 Comments: my compressor 200 avant-garde fan is running fast and it sounds like an aeroplane. And there are no indication of faults or indicator lighting on the dashboard. I think it is a dirty or faulty MAF Sensor. Please advise
September 13, 2015
  Followup from the Pelican Staff: If the fan is running at high speed, there may be an issue with the fan or the sensor. Check for fault codes. - Nick at Pelican Parts  
Kay Comments: Thank you for a wonderful platform and not only affordable parts but valuable knowledge. I have a w203 c200 kompressor and is leaking oil on the CAM...what fo you recommend. Thank you
September 9, 2015
  Followup from the Pelican Staff: Replace the gasket. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
MR Comments: The problem doesn't persist; it occurs more when driving in very hot weather specifically Here I'm talking about 35 C and higher plus heavy traffic idling and step driving. However, the engine starts after some repetitive cranking first thing in the morning; but never fails to start.
Some MB technicians told me to replace the crankcase sensor. Do you think such a sensor when faulty is responsible for the delayed starting, rough idling and engine cutting out intermittently?
Highly appreciate your answer.
August 31, 2015
  Followup from the Pelican Staff: It could cause a no start issue if faulty. - Nick at Pelican Parts  
MR Comments: My MB 240 model 2001 engine stalls when driving at heavy traffic, specially after idling for extended periods. The engine even cuts off at times. When I start off it loses power. The engine also revs quite a bit before starting at all times. I appreciate your help.
August 26, 2015
  Followup from the Pelican Staff: Could be fuel delivery or a sensor.

When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
ani1 Comments: Hello. i have a problem with my MB w203 coupe c220. After driving the car for a while it starts to sloe down and engine doesnt exeed 3000 rpm. Also it makes a noise but it doesnt show any error in the screen. What can i do?
May 9, 2015
  Followup from the Pelican Staff: Check the fuel delivery system and the exhaust system for excessive back pressure. - Nick at Pelican Parts  
Nik R Comments: Ok, so I installed new spark plugs all 12 of em and a new MAF sensor and I still get the car to run rough and its very jumpy while in idle with low rpm reading. Dont know what esle to do. I read here that the sensor may need to re-learn but dont know how to do this. Help please! Model 2003 E320
April 1, 2015
  Followup from the Pelican Staff: Is the check engine light on? Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
Mike Comments: Thanks for the help!
March 9, 2015
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Wai Bee Comments: How many liters of fuel can fill my ML320
September 20, 2014
  Followup from the Pelican Staff: Not sure, check your owners manual. - Nick at Pelican Parts  
Wai bee Comments: Great help,for me when driving my ML320 when step on the breaks at a particular speed the will no accelerate,when i turn the engine off and starts again the car will move again
September 15, 2014
  Followup from the Pelican Staff: You may have a brake caliper hanging up. Jack each corner of the vehicle and check for a seized wheel. - Nick at Pelican Parts  
danny Comments: thanks...... had a look at maf and it looks good but when i moved the breather tube. it had a split in other side of pipe. good info :-
August 15, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Sabin Comments: I have a 1998 MB E 320 which is dead. The engine starts up with a jump but it idles on high revs for a while then around 1000 rpm and then dies after say 30 secs or so. What's wrong and which part do I need?
May 28, 2014
  Followup from the Pelican Staff: I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and pressure fuel, volume and quality. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
tancio Comments: Is there no problem if I will change the maf sensor?according to somebody it needs to be reprogram if we will touch it.
May 13, 2014
  Followup from the Pelican Staff: Don't know what vehicle you have, but some models do require a relearn when the MAF is replaced. - Nick at Pelican Parts  
jos Comments: i have an S 320 with 80000 miles on it the engine just cuts off for no apparent reason when i leave it cool off for about 20 mins it starts no problem then cuts out after driving 7 to 8 miles what could be wrong
May 2, 2014
  Followup from the Pelican Staff: Could be a crank sensor. I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and pressure fuel, volume and quality. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
dave45056 Comments: Actually, The bit required to remove the MAF insert is a TS20. This is a 5 sided security torx bit.
See link here:
http://www.amazon.com/Silverhill-Point-Tamper-Proof-Piece/dp/B002P4YCGM/ref=sr_1_8?s=hi&ie=UTF8&qid=1396907676&sr=1-8

Also, Mercedes seems to have used TS20 and T20 Security Torx bolts through the years on the M112 engine. Later engines definitely use TS20, though.
April 7, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
Aaron Comments: Does anyone know what is needed to remove the security bolts on the MAF? I tried to find a five-sided driver/bit set bit nothing so far.
April 2, 2014
  Followup from the Pelican Staff: I believe this is called a Penta-Plus screw. - Nick at Pelican Parts  
dave45056 Comments: The bolts which hold the MAF sensor into the housing are NOT T20 Torx Security type. They are a 5 sided spline with a security feature. Not sure what this type of bolt is called, but a T20 Security bit won't work.
March 16, 2014
  Followup from the Pelican Staff: I believe this is called a Penta-Plus screw. - Nick at Pelican Parts  

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