Chevrolet Silverado / GMC Sierra. Service manual — part 1883

Fig. 25: Connecting Air Out Hose
Courtesy of GENERAL MOTORS CORP.

5. Connect the air out hose (2) of the EN-46999 (5) to the EN-46999-1 (1). See Special

Tools. Verify the air supply switch (4) is in the off position.

6. Connect the air in hose (6) of the EN-46999 (5) to a shop air source. See Special Tools.

7. Connect the 12-volt power supply connectors (7) of the EN-46999 (5) to a 12-volt power

supply. See Special Tools. 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 power cable (3) to the electrical connector of the manifold. See

Special Tools.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 26: Bleed Holes & Outlet Ports
Courtesy of GENERAL MOTORS CORP.

9. Turn the air supply switch of the EN-46999 to the ON position. See Special Tools. With

the air supply connected to the manifold assembly 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)
of the manifold.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 27: Testing Solenoid/Valves
Courtesy of GENERAL MOTORS CORP.

10. Position the manifold assembly 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 outlet
ports (2) of the manifold.

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 outlet
ports (3) of the manifold.

IMPORTANT: The manifold must be tested in the proper position to ensure

the solenoid/valves operate as designed.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 28: View Of Solenoid/Valves
Courtesy of GENERAL MOTORS CORP.

13. Reposition the manifold assembly 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 outlet
ports (4) of the manifold.

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 outlet
ports (1) of the manifold.

16. When the test is completed, turn the air source switch on the EN-46999 to the off position

and disconnect the tool from the 12-volt power supply, shop air source and manifold
assembly. See Special Tools.

17. 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.

18. 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.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado