AMM will be about $450 from the dealer or about $250 from this site. I bought mine from here, to support the site. Don't bother with the cheap ($100 or less) ones on eBay, they are new and good quality, but are typically the wrong Bosch part number and will make your car behave weirdly (trust me, I tried it). You can get the correct one from eBay for $250, but why not support this site?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I found pictures of the item online but I don't see where such a device could fit in my engine compartment. I am attaching a picture of my engine compartment. The intake (and the compressor) is on the driver's side of the engine.

Where's Waldo?

Attached Thumbnails

 

Check your PM's. Go to the link, see post #3 and click on the pdf file for the instructions.

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1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible

The mass air flow sensor is mounted in line behind the air filter box, it has a square electrical housing on the top . The harness connects at the top side of it. The removal requires a special clamp removal tool to release the clamps that hold it in place.

Thank you very much.

When I looked to buy the part, I saw that it was not the "tube like thing" that I saw when I did the Google image search. It is much flatter than that and I remembered seeing it from work I did previously.

Mercedes was nice enough to put the electrical connector right on top, so I've cleaned that now (without any other disassembly) but the Check Engine light is still on. If a dirty connector was the problem, how long before the light goes out?

The linked information indicates that the more common prolbem is oil in the harness going to the O2 sensor. I replaced my O2 sensor not too long ago, and I do remember there being some wetness in the connectors. Perhaps I should get back under there and spray some contact cleaner on that plug?

For that code it may need to be erased with a scanner.
Bill

Nobody has ever posted about "dirty connector."

This is a hot wire MAF and the cleaning is of that wire, which is internal to the unit. This unit measures density/volume of incoming air by calculating how much that air cools the hot wire.

All very interesting, of course, because this cleaning isn't going to work in any event.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

All of the measurements and for that matter the establishment of air density and flow over the element are based soley on very slight voltage variations seen by the control unit. ANY single or multiple instances that can effect the current flow will have the ability to alter the factors that establish the air mass
traveling through the assembly...... so a corroded connection caused by disimelar materials being in contact in a varying environment can alter the readings seen by the control unit.
Bill

I am equally skeptical about the connector theory, and I don't recall ever hearing about that before. For the record, these AMMs are thin-film type, not hot wire (I believe). Some people have reported success with cleaning, but not very many. I tried, and it did.... nothing.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

LOL. Probably not, but I don't see the harm in trying. Like I said originally, the car drives just fine. If I didn't have an impending state inspection I'd just keep driving it as-is. If cleaning the sensor works long enough to drive to the inspection station then I have all the time in the world to noodle it over or save up money for parts and tools.

David

I searched this site and only found the part for $450. I'd like to support this site, I believe you guys are a big help. Can you link me to the $250 part?

In the meanwhile, I am going to try cleaning the AMM/MAF. Seems like a no-lose procedure. If it doesn't work, I'll be no worse off than I am today.

If I erase the code with a scanner, I presume I'll have to drive some number of miles still before I can go for my vehicle inspection?

David

I still have not purchased a new MAF. There was a problem locating the special flexible hose clamp pliers (one source kept telling me they'd have it the next day, and the next, and the next).

So I still want to buy the part here to support you guys, but I'm not going to pay an extra $200 for it. I can buy it locally for $266. Show me where I can get it "here" for anything close to that.

You can call Phil and see what he can do.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra