Vacuum Check Valve Inspection

Tools Required 

J 23738-A  Hand Vacuum Pump

Fig 1: Removing Vacuum Check Valve And Auxiliary Intake Air System
Courtesy of GENERAL MOTORS CORP.
1. Remove the vacuum check valve (1) from the auxiliary intake air system.
Fig 2: Vacuum Pressure Test
Courtesy of GENERAL MOTORS CORP.
2. Connect the J 23738-A  or an equivalent hand vacuum pump to the intake manifold side of the vacuum check valve.
3. Attempt to apply a vacuum of 34 kPa (254 mm Hg, 10 in. Hg) to the vacuum check valve.
4. The check valve SHOULD NOT hold vacuum pressure.
Fig 3: Vacuum Pump To Side Check Valve
Courtesy of GENERAL MOTORS CORP.
5. Disconnect the J 23738-A  or an equivalent hand vacuum pump from the check valve.
6. Connect the J 23738-A  or an equivalent hand vacuum pump to the other side of the check valve.
7. Apply a vacuum of 34 kPa (254 mm Hg, 10 in. Hg) to the vacuum check valve.
8. The check valve SHOULD hold vacuum pressure.
9. Replace the vacuum check valve if the valve failed either of the tests above.
Fig 4: Installing Vacuum Check Valve And Auxiliary Intake Air System
Courtesy of GENERAL MOTORS CORP.
10. Install the vacuum check valve (1).
11. Ensure that the check valve (1) is installed with the side that holds vacuum toward the intake air control solenoid (3).