Impreza Sedan AWD F4-1820cc 1.8L SOHC (1993)
Idle Up Control Valve: Description and Operation
FICD Device - 1, PCV Valve - 2
PURPOSE
The fast idle control device (FICD) allows additional air to bypass the throttle plate during air conditioning operation.
LOCATION
The FICD is bolted on top of #2 intake runner. (#1 in image).
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.