Air Mass Meter / Sensor for 1999 CLK 320

I have to replace the air mass meter (sensor) for 1999 CLK 320. It looks like an easy DIY - is there anything I have to be careful about? The computer will need to be reset - is there a way to do it by myself?
I have an option of purchaing a BOSCH or an aftermarket part of e-bay. Any sugegstions / experiences?
Any advice will be greatly appreciated.
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Are you sure you need to replace it? My 1998 was throwing code P0170 which, among other things, could be a bad air mass meter. Over six months I replaced a number of less costly possible causes, but it looked like the air mass meter needed to be replaced. A few weeks ago I took the air mass meter apart and gave it a thorough cleaning with carb & choke cleaner. I figured that since I was going to replace it anyway, I had little to risk by attempting to clean it. Within a few hundred miles, the CEL was off and the car runs great.
--
Steve Heath



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Ditto.
I had the same experience with the AMS on my '97 E320 straight six.
A very very careful cleaning eliminated the codes etc. with no return of the problem.
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Did you guys reset the computer to clear the light?
My car has almost 55000 miles on it, and I have read that this is about the time that the air mass meter goes bad. But I will try the cleaning first.
What carb and choke cleaner did you use?
Any advice on how to take it apart and put it back together? Special precautions / tools needed?
Many thanks.
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My car had done only about 37K when the check engine light came on so a failed sensor was unlikely. Code PO170 didn't describe the exact problem so I paid the dealer to diagnose and estimate the repair and its cost - MAS about $550 - $600. (On line part price $260.) Then I thought about the project and decided to first try cleaning the MAS and replace it DIY if cleaning failed.
My E320's MAS has two pieces: the larger 3" x 4" "stovepipe" housing and the sensor itself which screws into the side of the "stovepipe".
Removing the "stovepipe" is easy. Then one removes the sensor from the "stovepipe".
I used an old fashioned (smoker's) pipe cleaner to simply clean the sensor's wires - very, very carefully, in daylight.
I didn't use any solvents for there are no petroleum deposits on the sensor.
Cleaning worked, there's been no further messages.
I cleared the codes with my code reader.
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Do you need special TORX bits to remove the screws? Where do you get those?
Thanks.
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I did nothing to clear the light. Just drove it and it cleared itself in a few days (I drive > 120 mi/day.) You can reset the computer by disconnecting the battery, just make sure you have your radio code handy.
I used carb&choke cleaner to clean it, and the whole job took about 20 minutes. Just be sure not to touch any of the sensor components.
--
Steve Heath



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Steve, how did you take it apart? I am told it needs special tools to open the tamper-proof torx screws?
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A while back I had bought a set of security bits. They've come in handy for everything from the car to McDonalds happy meal toys (don't ask.)
This is the set I got. I don't remember where I bought it. http://www.pccables.com/21050.htm
--
Steve Heath



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