Acoustic Control Induction System: Highlander
- Acoustic Control Induction System (ACIS) uses 2 intake air control valves, one on end of air intake chamber and one near throttle bodies. See Figure. Intake air control valve on end of air intake chamber may also be referred to as No. 2 intake air control valve. Intake air control valve near throttle bodies may also be referred to as No. 1 intake air control valve. Operation of actuator valve for each intake air control valve should be checked. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve for appropriate intake air control valve. See Figure. Actuator valve may also be referred to an actuator.
- Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. See Figure. Start engine. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate intake air control valve No. 1 and 2 Vacuum Switching Valves (VSVs) and note vacuum reading. Intake air control valve VSVs may also be referred to as ACIS VSVs. When each intake air control valve VSV is off, ensure no vacuum reading is obtained. When each intake air control valve VSV is on, ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls inward. If actuator valve rod does not pull inward, go to next step. If actuator valve rod pulls inward, go to step 4.
- Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod pulls inward and remains pulled inward for at least one minute. If actuator valve operates properly, reconnect vacuum hose and go to next step. If actuator valve does not operate properly, replace intake air control valve assembly. See INTAKE AIR CONTROL VALVE under AIR INDUCTION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
- Ensure transaxle is in park. While monitoring data monitor on hand-held tester, check that intake air control valve No. 1 and 2 VSVs turn on and off in relation to throttle opening percentage and engine RPM. See Fig 1. Value in illustration is only for reference, as throttle opening percentage may operate diversely depending on operating conditions. Shut engine off. Remove hand-held tester and reconnect vacuum hose. If system operates properly, test is complete. If system does not operate as specified, check ACIS control circuit. See ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS.
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