Mercedes-Benz Electronic Idle Speed Control

The system controls a variable air bleed into the intake system. Idle speed is held constant by increasing or decreasing the amount of extra air injected through an insulating sleeve around each fuel injector. A high idle speed is maintained when engine temperature is below 107°F (40°C), then idle speed drops to a constant low idle RPM when engine temperature is above 107°F (40°C). The idle speed control system consists of an idle speed adjuster, intake air distributor and a electronic control unit.