Function And Operation Principle

Variable Intake manifold Solenoid (VIS) valve is installed on the intake manifold. The VIS valve controls the vacuum modulator which activates a valve in the intake manifold. The PCM opens or closes this valve according to engine condition (Refer to VIS VALVE REFERENCE CHART ).

Fig 1: Identifying Variable Intake Solenoid (VIS) Valve

Courtesy of KIA MOTORS AMERICA, INC.

VIS VALVE OPERATION - VARIABLE INTAKE SOLENOID VALVE

Engine Condition	VIS Valve	Operation
Medium speed	Closed	Increasing engine performance in low engine speed by reducing intake interference among cylinders
Low / High speed	Open	Minimizing intake resistance by shortening intake manifold length and increasing area of air entrance

Fig 2: Identifying Variable Intake Solenoid Valve Air Flow At Low/High & Medium Speeds

Courtesy of KIA MOTORS AMERICA, INC.