Lanos S Hatchback L4-1.6L DOHC D-TEC MFI (1999)
Variable Geometry Induction System (VGIS): Description and Operation
The variable geometry induction system (VGIS) is used to add more responsive acceleration to the dual overhead camshaft (DOHC) engines. Under
certain conditions, the powertrain control module (PCM)/engine control module (ECM) activates the VGIS solenoid, allowing the stored vacuum to
actuate the secondary throttle control valve. The secondary throttle control valve then opens the secondary throttle plates, which are internal to the intake
manifold and plenum assembly. This allows for increased airflow into the engine creating more responsive acceleration.