Unclip exhaust gas recirculation cooler changeover valve -N345- from retainer located on front of intake manifold.
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Pull vacuum hose at lower connection -arrow in I- off exhaust gas recirculation cooler changeover valve -N345- and off charge pressure control solenoid valve -N75--arrow in II-.
Continuation for all engine codes
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Seal open hose ends with suitable blanking plugs.
Note
Do not use screws or threaded bolts.
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Pull vacuum hose -arrow- off connection piece of vacuum pump.
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Connect hand vacuum pump -VAS 6213- to disconnected hose and generate a vacuum of 0.6 bar.
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Observe hand vacuum pump pressure gauge for approx. 30 seconds.
l
Vacuum must not drop.
If vacuum drops:
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Locate damage or leak in hose and replace corresponding length of hose.
If pressure does not drop:
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First pull hose off hand vacuum pump -VAS 6213-.
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Remove one of the blanking plugs from hose ends.
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If the non-return valve functions properly, a clear hiss is audible when vacuum in vacuum reservoir is released.