420 & 560 Series

The idle speed air valve is an electro-magnetic disc valve. It has a 2-pin electrical connector. The idle speed air valve has the following functions:

• Without current, a spring keeps the valve fully open. With the ignition turned on, the valve is also fully open.
• At idle speed (depending on engine load), the idle speed control unit supplies a current of less than 1000 mA to the idle speed air valve. This current determines valve opening and idle speed.
• The idle speed is range is controlled by coolant temperature.
• The idle speed air valve by-pass is normally open for the 420 engine and closed on the 560 engine.