How to clean MAF?

[serndipity]

Although my 2001 CLK320's CEL has been on 6 months, the runs normally. However, with a CEL on, won't pass state inspection in MA next month. Codes are P0170 and P0173.

I have searched and read all the discussions and decided to try cleaning my MAF last weekend.

I removed the MAF and then took out the sensor insert to clean. The only thing visable was an electronic part that was a wire with a tiny glass cylinder in the middle (diode or termisiter). What I could not find was the coiled wire, metal plates etc. that have been discussed.

At the end of the sensor insert, there were some small square openings and there appeared to be aditional metal objects inside. However, the openings were to small to get at them. So I attempted the cleaning by submersing the sensor in a container of denatured alcohol and shaking it. Reinstalled the MAF and the CEL remains on (manual says that it will go off after 3 complete cycles of normal operation).

The MAF is MB part # 112 094 00 48, Bosch # 0 280 217 515. BTW, the Bosch web site shows the # as 0 280 217 516 (w/ the word "new" added).

At the end, were the small square holes were, it appeared that there might have been a removable cover section. Since it ddn't come off with reasonable force....the did the alcohol bath.

Any advise as to how this could have cleaned the sensor?

[manny]

The Bosch number probably refers to a " New & improved " version.
My understanding is that Electrical Contact Spray Cleaner will work well without hurting anything.
If that doesn't work, you may have to get one of these " New " sensors.

[JML430]

I had the exact same problem with my MAF on a '01 ML 430. I sprayed brake cleaner into the square opening that you referred to:

"At the end of the sensor insert, there were some small square openings and there appeared to be aditional metal objects inside".

That is the wire you need to clean. From my limited understanding of how the MAF works, if dust collects on this wire it will impede the cooling effect of the air stream and throw the sensor off.

Initially I was disappointed with this approach because the CEL remained on. However, my understanding is the computer needs a couple of 'error-free' starts before it resets. 3 or 4 starts later it went out and hasn't come on since (only 3 days and counting). So I will keep my fingers crossed for the time being.

Good luck.