dash warnings
 

I've had a '97 E300D for 3 yrs and keep getting dash warnings, about 1/2 of which are erroneous. The "lamp defective" I am told can be fixed by removing, cleaning, and reinstalling each bulb until I find the culprit (all lamps are functioning fine so far as I can tell), the washer-level warning came on both before and after adding washer fluid, the "engine electronics" comes on after changing oil but stops after a week or so. I've had a few items replaced because of codes tested after "engine electronics" comes on, but I don't know whether to trust the system. The car has 205K on it but strikes me so far as much less reliable than my old 240D with 340K mi on it.

Any advice??