I had problems with my '93 500E ASR last year. After driving the car a couple of minutes, the ASR light would illuminate & it would definetely quit working (kind of a cheap defeat switch if you could live with light & YES the car is quicker without ASR, trust me) but, no limp home mode. At my 60k service, the dealer quoted a couple grand for some ASR control unit. WHATEVER! I lived with it for a couple of months than went on an extended vacation. This is where it gets interesting. When I got back, I started the car to go run an errand. It clattered like crazy. NOT GOOD NOISES! I removed the air cleaner assembly & started the car several times. Each time it got a little better. The handy broomstick listening device told me it was in the upper end, probably an oil leak down of some sort since the car had sat for a while. After about the tenth start, Presto! No noise. Here is where the ASR comes in. I haven't seen the light & it has worked great since then. i don't know if running the car with the air cleaner off reset something or not but it sure would be an easy way to try & fix your problem. The MBZ gods smiled on me that day, maybe they will smile on you, too. Good Luck!
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