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Home >> Infiniti >> 2004 >> M45 >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P1491: Vacuum Cut Valve Bypass Valve >> Overall Function Check >> With GST
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With GST

  1. Remove vacuum cut valve and vacuum cut valve bypass valve as an assembly.
  2. Apply vacuum to port and check that there is no suction from port B. 
  3. Apply vacuum to port and check that there is suction from port A. 
  4. Blow air in port and check that there is a resistance to flow out of port A. 
  5. Supply battery voltage to the terminal.
    Fig 1: Manually Activating Vacuum Cut Valve Bypass Valve
    G00796535Courtesy of NISSAN MOTOR CO., U.S.A.
  6. Blow air in port and check that air flows freely out of port B. 
  7. Blow air in port and check that air flows freely out of port A. 
  8. If NG, go to DIAGNOSTIC PROCEDURE .