Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing

Special Tools

• EN-46999  Active Fuel Management Tester
• EN-46999-18  Active Fuel Management Tester Air Adapter
• EN-46999-20  Active Fuel Management Tester Harness - Small Block V8

For equivalent regional tools, refer to Special Tools

Courtesy of GENERAL MOTORS COMPANY

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

• Proper operation
• A stuck open condition - constant air flow
• A stuck closed condition - no air flow
• A flow restriction within the manifold

1. Individually depress each of the buttons 1 - 4 on the EN-46999  tester 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.
   • 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.

2. Courtesy of GENERAL MOTORS COMPANY

   Do not lift the manifold assembly by the electrical lead frame.

3. Courtesy of GENERAL MOTORS COMPANY

   Connect EN-46999-18  active fuel management tester air adapter (9) to the air out hose (2) of the EN-46999  tester (5). This will make it possible to connect an air nozzle fitted with a standard 1/4 in NPT female air fitting. Verify the air supply switch (4) is in the off position.

4. Connect the air out hose (6) of the EN-46999  tester (5) to a shop air source.
5. Connect the 12 volt power supply connectors (7) of the EN-46999  tester (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.
6. Connect the EN-46999-20  active fuel management tester harness - small block V8 (3) to the tester. Connect EN-46999-20  active fuel management tester harness - small block V8 to the electrical connector of the manifold.
7. Connect an air nozzle fitted with a tapered rubber tip to EN-46999-18  active fuel management tester air adapter (9). Hold the tip of the air nozzle in the oil passage directly below the Valve Lifter Oil Manifold Oil Filter (1).

8. Courtesy of GENERAL MOTORS COMPANY

   Turn the air supply switch of the EN-46999  tester to the ON position. With the air supply connected to the manifold assembly and the solenoid/valves in the closed position, a limited amount of air will exit from the outlet ports (1, 2) of the manifold.

9. Courtesy of GENERAL MOTORS COMPANY

   NOTE:

   The manifold must be tested in the proper position to ensure the solenoid/valves operate as designed.

   Position the manifold assembly onto a bench at a 45 degree angle in order to test solenoid/valves 1 and 4.

10. 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 outlet ports (2) of the manifold.
11. 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 outlet ports (3) of the manifold.

12. Courtesy of GENERAL MOTORS COMPANY

    Reposition the manifold assembly onto a bench at a 45 degree angle in order to test solenoid/valves 2 and 3.

13. 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 outlet ports (4) of the manifold.
14. 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 outlet ports (1) of the manifold.
15. When the test is completed, turn the air source switch on the EN-46999  tester to the off position and disconnect the tool from the 12 volt power supply, and shop air source. Disconnect air nozzle.
16. If after testing, it has been determined that one or more of the solenoid/valves is not functioning properly, replace the manifold as an assembly.
17. If after testing, it has been determined that the solenoid/valves are functioning properly, replace the valve lifters as required. Both intake and exhaust lifters should be replaced in pairs.