1993 Mercedes-Benz 300E Q&A

1993 Mercedes-Benz 300E Question: 1991 300e what microprocessor controls the idle air control valve?

I replaced the idle air control valve because when the car is warmed up and I come to a full stop at idle with the car in drive, the idle drops too low, below 500 rpms. A mechanic cleaned the electrical plug which plugs into a component that is also connected to the idle control valve and it worked fine for a few days but now the too low idle has returned.? I thought the microprocessor might be bad but I don't know what, where or how much it is. -
Answer 1
ck circuit for high resistance. that would cause this or poss dirty throttle body -