Air Control Valve: Inspection

TURN AIR CONDITIONING SWITCH OFF
CHECK IDLE-UP
1. Start the engine and run it at idle.
2. Fully turn the steering wheel.
3. Check that the engine speed decrease when the vacuum hose of the air control valve is pinched.
4. Check that the engine speed increase when the hose is released.
  
  Fig 1: Checking Vacuum Hose
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002