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Checking Valve With Vacuum Pump

  1. Attach vacuum pump (VAG 1390) to by-pass valve.
  2. Operate vacuum pump. By-Pass valve must open. See Fig 1.
  3. After approximately 30 seconds, operate venting valve of vacuum pump (release vacuum). By-Pass valve must close.
  4. If by-pass valve does not open or close, or if valve plate is leaking with cut-off closed, replace valve.
  5. Secure connections of by-pass valve with hose with hose clips.
Fig 1: Checking By-Pass Valve With Vacuum Pump
G00177364Courtesy of AUDI OF AMERICA, INC.