TT Quattro Roadster L4-1.8L Turbo (AMU) (2002)
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Intercooler: Testing and Inspection
Mechanical Air Recirculation Valve, Testing
Notes:
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The mechanical air recirculation valve located upstream of the turbocharger. It is opened by vacuum from the electrically operated air recirculation
valve for turbocharger - N249 when the engine is on overrun, underpart load, or when idling. This disperses the pressurized air (charge pressure)
upstream of the throttle valve, and thus keeps the turbocharger rotating at a higher speed.
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Check the air recirculation valve if the engine is not producing full power, or jerking when the throttle is opened and closed.
Special tools, testers and auxiliary items required
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V.A.G 1390
Test sequence
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Connect vacuum pump V.A.G 1390 to air recirculation valve.
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Operate vacuum pump.
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Air recirculation valve should open - arrow -.
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Operate air vent valve on vacuum pump after about 30 seconds.
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Air recirculation valve should close - arrow -.
If the air recirculation valve does not open and close as specified, or if the valve plate does not seal properly when the valve is closed:
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Replace the air recirculation valve. Secure the connections on the valve with screw - type clips.
