Impreza Coupe FWD F4-1820cc 1.8L SOHC (1995)
Fast Idle Control Device: Description and Operation
PURPOSE/OPERATION
The fast idle control device (FICD) allows additional air to bypass the throttle plate during air conditioning operation. When the A/C compressor
is turned "ON," the ECM responds to the increased load on the engine and by energizing the fast idle solenoid. When energized, the solenoid
opens an idle bypass passage, allowing additional air around the throttle valve and raising the idle speed. A fast idle adjusting screw regulates the
amount of bypass air allowed when the solenoid is energized. A faulty fast idle solenoid does not set a trouble code.