Impreza RS Coupe AWD F4-2.5L SOHC (1999)
EGR Control Solenoid: Description and Operation
Controls when EGR operation occurs. The EGR control solenoid valve is in the vacuum line between the throttle body and EGR valve. When energized
by the ECU, the valve opens allowing vacuum to the EGR valve diaphragm, opening the EGR valve. The control unit calculates various inputs such as
engine temperature and speed in determining when to operate the solenoid valve.
