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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 G8 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing

Tools Required

    • EN-46999 EN-46999 Displacement on Demand Tester.
    • EN-46999-1 EN-46999-1 Displacement on Demand Tester Air Adapter.
    • EN-46999-5 EN-46999-5 Displacement on Demand Tester Harness - Small Block V8.

Important: 

   • A minimum shop air source of 206 kPa (30 psi) is required for Valve Lifter Oil Manifold (VLOM) testing.
   • A water bleed is located on the side of the EN-46999 EN-46999. Occasionally, depress the valve in order to remove excess water from the tool.


Object Number: 2043999 Size: SH

The VLOM bench test provides a maximum 206 kPa (30 psi) of filtered shop air to the VLOM and will test each solenoid/valve for the following conditions:

    • Correct operation.
    • A stuck open condition - constant air flow.
    • A stuck closed condition - no air flow.
    • A flow restriction within the VLOM.
  1. Individually depress each of the buttons 1-4 on the EN-46999 EN-46999 in order to activate each of the solenoid/valves. When activating each solenoid/valve, a loud click should be heard from the solenoid and an increased amount of air will exit the outlet ports.
    2. • Button 1 will energize the solenoid/valve 1 for engine cylinder number 1.
    • Button 2 will energize the solenoid/valve 2 for engine cylinder number 4.
    • Button 3 will energize the solenoid/valve 3 for engine cylinder number 6.
    • Button 4 will energize the solenoid/valve 4 for engine cylinder number 7.

    Object Number: 2044001 Size: SH
  2. DO NOT lift the VLOM assembly (2) by the electrical lead frame (1).

    3. Object Number: 2044000 Size: SH
  3. Install the EN-46999-1 EN-46999-1  (1) to the VLOM (3).

    4. Notice: Refer to Fastener Notice in the Preface section.

  4. Install 2 of the manifold bolts (2) to the EN-46999-1 EN-46999-1 .

    5. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).


    Object Number: 2044004 Size: SH
  5. Connect the air out hose (2) of the EN-46999 EN-46999  (5) to the EN-46999-1 EN-46999-1  (1). Verify the air supply switch (4) is in the off position.
  6. Connect the air in hose (6) of the EN-46999 EN-46999  (5) to a shop air source.
  7. Connect the 12 volt power supply connectors (7) of the EN-46999 EN-46999 (5) to a 12 volt power supply. Verify the Power light (8) on the tool is illuminated. If the light on the tool is not illuminated when connected to a 12 volt power supply, test and/or replace the 3 amp fuse.
  8. Connect the EN-46999-5 EN-46999-5 power cable (3) to the VLOM electrical connector (9).

    9. Object Number: 2044007 Size: SH
  9. Turn the air supply switch of the EN-46999 EN-46999 to the ON position. With the air supply connected to the VLOM and the solenoid/valves in the closed position, a limited amount of air will exit each of the bleed holes (3) and outlet ports (1, 2).

    10. Object Number: 2044008 Size: SH

    Important: The VLOM must be tested in the correct position to ensure the solenoid/valves operate as designed.

  10. Position the VLOM onto a bench at a 45 degree angle in order to test solenoid/valves (1) and (4).
  11. Depress button number 1 on the tool to activate solenoid/valve 1. With button 1 depressed, the solenoid/valve (1) should open, allowing an increased amount of air to exit the VLOM outlet ports (2).
  12. Depress button number 4 on the tool to activate solenoid/valve (4). With button 4 depressed, the solenoid/valve (4) should open, allowing an increased amount of air to exit the VLOM outlet ports (3).

    13. Object Number: 2044010 Size: SH
  13. Reposition the VLOM onto a bench at a 45 degree angle in order to test solenoid/valves (2) and (3).
  14. Depress button number 2 on the tool to activate solenoid/valve (2). With button 2 depressed, the solenoid/valve (2) should open, allowing an increased amount of air to exit the VLOM outlet ports (4).
  15. Depress button number 3 on the tool to activate solenoid/valve (3). With button 3 depressed, the solenoid/valve (3) should open, allowing an increased amount of air to exit the VLOM outlet ports (1).
  16. When the test is completed, turn the air source switch on the EN-46999 EN-46999 to the off position and disconnect the tool from the 12 volt power supply, shop air source and VLOM.
  17. If after testing, it has been determined that one or more of the solenoid/valves is not functioning correctly, replace the VLOM as an assembly.
  18. If after testing, it has been determined that the solenoid/valves are functioning correctly, replace the valve lifters as required. Both intake and exhaust lifters should be replaced in pairs.