Variable Induction System: Description and Operation

PURPOSE
The Acoustic Control Induction System (ACIS) is designed to allow increased performance in all driving ranges by changing the effective intake manifold length in two stages as determined by the Engine Control Module (ECM).
OPERATION
At specific times determined by the ECM based on various sensor inputs, the ACIS Vacuum Switching Valve is signaled to open or close which controls the vacuum source to the ACIS Actuator, which in turn opens or closes the Intake Air Control Valve. This action changes the effective intake manifold length.