A buddy of mine has a 2000 E430 with about 105,000 miles. The check engine light came on, but the car ran just fine. His wife took the car to the dealership and they called to notify him the MAF was bad. Replacement parts were available and it could be fixed in a few hours, but a MAF replacement costs $500 or so.

He had it done but got the old MAF back. He says it looks visually fine, no dirt or other evidence of physical damage. Is there a way to check these out, out of the car? What typically fails? Thanks, Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)