The Throttle Flap Control Solenoid Valve controls the throttle flap vacuum valve which activates the throttle flap installed inside the throttle body. This throttle flap control system functions "Anti-judder function" and "Intake air control for EGR".

Ⅰ. Anti-judder function: When engine is shut off, the ECM can prevent intake air from entering to intake manifold by fully closing the throttle valve for 1.5 seconds (95% ＜ Duty ＜ 97%) to reduce engine vibration.

Ⅱ. Intake air control for EGR: When exhaust gas pressure is equal to or lower than intake air pressure (for example, when low engine speed), the exhaust gas would not enter to the intake manifold. At this time, the ECM partially closes the throttle valve (5% ＜ Duty ＜ 94%) to reduce the intake air quantity. The intake air pressure thus is lower than the exhaust gas pressure.