Variable Induction System Check

Tee a vacuum gauge into vacuum line between the vacuum switching valve and the Toyota Variable Induction System (T-VIS) diaphragm. Connect tachometer to engine. See ADJUSTMENTS article for correct tachometer attachment.
Start engine and warm to normal operating temperature. Vacuum gauge should show high vacuum at idle (internal throttle valve closed).
Increase engine speed to above 5000 RPM on Corolla and MR2, or 4400 on Celica. Vacuum gauge should indicate zero. If not, test vacuum switching valve and use hand held vacuum pump to test if T-VIS diaphragm holds vacuum.

Fig 1: Testing Variable Induction System - Celica
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
To test vacuum switching valve, remove valve from vehicle. On Celica (3S-GE), valve is on top of cylinder head near No. 2 spark plug; on Celica (3S-GTE), valve is top of the intake manifold.
Ensure resistance across vacuum switching valve wiring terminals is 33-39 ohms. Ensure there is no continuity between wiring terminals and body of valve. To check air flow through valve.

Fig 2: Testing 3S-GE Variable Induction System VSV

Fig 3: Testing 3S-GTE Variable Induction System VSV