Of course you should try cleaning first. After I had mine replaced, at 57,000 miles, at a cost of $512 I did a little web searching and found a lot of info on cleaning MAF sensors. Just because an auto dealer's Service Dept. replaces the entire assembly doesn't mean its in the customer's best interest. They make a lot of money on the parts and labor. It seems to me MB has all too many failures of the MAF sensors. I read somewhere the air cleaner element may be losing some very small fibers that catch on the sensor wires and screw up the signal to the computer. Could it be that this is why the air cleaner element design was changed?

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Tom H.