For your '94 E420. . . .
it does have a malfunction counter. This counter is decremented by one count for every 'trip'. A trip is defined as KO, running at great than 5mph and longer than 5 minutes (if I remember the numbers correctly).
So if the CE lights and for next 'x' trips if the DTC doesn't occur, the counter is reduced by one. So that's how the light goes out.
5 blinks = EGR recirculation faulty. Probably plugged!
Regards . . . . JimF
'94 S500 Cpe
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