Intake Air Control Valve
WARNING: This page is about a different car, the 2002 Lexus SC 430, 2002 Lexus LS 430, 2002 Lexus IS 300, 2002 Lexus GS 430, and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
- Remove throttle body. SeeTHROTTLE BODY under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Remove upper and lower intake manifolds. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. Install a 3-way vacuum "T" fitting in vacuum hose between Intake Air Control Valve (IACV) actuator and ACIS Vacuum Switching Valve (VSV). See Fig 1. Reinstall intake manifolds and throttle body.
- Connect a vacuum gauge to vacuum "T" fitting. Start engine. With engine idling, ensure vacuum reading is about 11.8 in. Hg, and IACV actuator rod is pulled out. Snap accelerator to Wide Open Throttle (WOT) position. Vacuum should not exist during WOT and IACV actuator rod should return. If vacuum is not as specified or actuator valve rod fails to pull out, go to next step.
- Remove IACV. Apply about 11.8 in. Hg to IACV actuator. If IACV actuator rod does not move, replace IACV actuator. If IACV actuator rod moves, check to see if diaphragm holds vacuum for at least one minute. If diaphragm does not hold vacuum, replace actuator. If diaphragm holds vacuum, check vacuum hoses and vacuum tank. See ACIS VACUUM TANK .