ACIS Control Circuit [06/2018 - 08/2021]: Description

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ACIS (Acoustic Control Induction System) controls the opening and closing the intake air control valve sub-assembly built into the intake air surge tank assembly to increase the intake efficiency according to the engine load.

When the engine speed is between 0 and 4300 rpm and the throttle valve opening angle is 30° or more, the ECM activates the No. 1 vacuum switching valve (for intake air control valve sub-assembly) which then applies vacuum from the vacuum pump assembly to the diaphragm actuator sub-assembly and closes the intake air control valve sub-assembly.

When the engine speed and/or throttle valve opening angle are not as specified above, the ECM deactivates the No. 1 vacuum switching valve (for intake air control valve sub-assembly), causing the intake air control valve sub-assembly to open.