1994 Mercedes E 320 Sedan has red check engine light on. Upon following the procedure to read the code, there were six blinks. DTC 6 reads Idle Speed Control inoperative. Can some one suggest what needs to be done, where is the idle speed control, is this part repairable and how it is done or do I need to buy a new one (cost?)? I have no speed surge and it idles around 700 - 800 RPM. The vehicle is running great.

Any help will be appreciated.

Pete