Air Control Valve: Inspection

WARNING: This page is about a different car, the 2005 Lexus GS 430 and 2005 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

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 speeds decreases when the vacuum hose of the air control valve is pinched.
4. Check that the engine speeds increases when the hose is released.
  
  Fig 1: Pinching Vacuum Hoses
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