Toyota 4-Runner 1985 Repair Manual page 145

EMISSION CONTROL SYSTEMS (CARB.) -
Air Suction (AS) System
EC-45
EC010l
INSPECTION OF VTV
CHECK VTV BY BLOWING AIR INTO EACH SIDE
(a) Check that air flows without resistance from B to A.
(b) Check that air flows with difficulty from A to B.
If a problem is found, replace the VTV.
A03063