Variable Intake manifold Solenoid (VIS) valves are installed
on the intake manifold (VIS Valve 1) and the surge tank (VIS Valve 2).
These VIS valve 1 and 2 control vacuum modulators which activate valves
in the intake manifold and the surge tank. These valves opens or closes
by ECM according to engine condition (Refer to the table below).

Other information:
Follow Normal Maintenance
Schedule if the vehicle is usually
operated where none of the following
conditions apply. If any of the following
conditions apply, you must follow
the Maintenance Under Severe
Usage Conditions.
Repeated short distance driving.
Driving in dusty conditions ...
Cluster ionizer
When the Engine Start/Stop button
is in the ON position, the clean air
function turns on automatically.
Also, the clean air function turns off
automatically, when the Engine
Start/Stop button is in the OFF position.
Smart ventilation
When driving and the heater and air
...