DTC P0660: Intake Manifold Tuning Valve Control Circuit/Open: General Description

The Variable Intake System (VIS) varies the length of the intake manifold to generate maximum power at certain RPM. The VIS lengthens the intake manifold to improve the torque at low RPM when vehicle speed is low while it shortens intake manifold to raise torque at high RPM when vehicle speed is high. The ECM/PCM controls VIS using RPM signal.