Jetta GLX V6-2.8L (AFP) (2002)
Variable Induction Control Valve: Testing and Inspection
With Manufacturer's Scan Tool
Intake Manifold Tuning (IMT) Valve -N156-, Checking
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Perform check only if performance is poor.
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The intake manifold change-over from long to short intake ports occurs at approx. 4000 RPM.
Special tools and equipment
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VAG1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
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VAG1390 hand vacuum pump
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Multimeter (Fluke 83 or equivalent)
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VW1594 adapter set
Checking function
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Start engine and run at idle.
The change-over barrel in intake manifold is positioned at short passageway.
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Fully depress accelerator pedal, then release before 4000 RPM.
The actuating element must rotate the barrel in the intake manifold (arrow).
If the positioning element does not perform the change-over sequence:
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First check activation of Intake Manifold Tuning (IMT) valve -N156- via output Diagnostic Test Mode (DTM).
If the activation is OK:
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Connect scan tool or vehicle test system.