A8L Quattro Sedan V8-4.2L (AUX) (2001)
Variable Induction Control Valve: Testing and Inspection
Change-Over Valve N156 & Intake Tuning (IMT) Valve 2 N261 Check
Intake Manifold Change-Over Valve -N156 and Intake Manifold Tuning (IMT) Valve -2- -N261, Checking
Checking Intake Manifold Change-Over Valve -N156 and Intake Manifold Tuning (IMT) Valve -2- -N261
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Run engine at idling speed for 2 or 3 minutes to build up vacuum.
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Switch engine off.
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Switch ignition on.
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Perform output Diagnostic Test Mode (DTM) and activate solenoid valves for intake manifold change-over. Refer to Scan Tool Testing/Output
Diagnostic Test Mode (DTM) (Function 03) See: Computers and Control Systems/Testing and Inspection
Indicated on display
Output Diagnostic Test Mode
->
Intake manifold change-over valve -N156
Indicated on display
Output Diagnostic Test Mode
->
Intake manifold tuning valve 2 -N261
The valves should click (clicking can be heard and felt). After 1 minute the DTM is terminated.
If one of the valves does not click.
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Switch ignition off.
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Disconnect harness connector from relevant intake manifold change-over solenoid valve.
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Measure resistance between valve contacts using Fluke 83 (or equivalent) multimeter.