Step by step explanation on how an automotive idle air control valve works, though
various manufacturer's create different styles of valve, the concept is the same.
Step 1 - The idle air control valve is located
on the throttle bore (in most cases) and is designed to adjust engine air intake
at idle which controls the engine idle speed. The PCM receives feedback data
from various sensors to send output signals designed to adjust the air passage
open or closed which adjusts the engine idle speed. At engine speeds above idle,
the valve is not used and does not effect the engine. Engine idle speeds are not