Subject : DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Check Engine Light On (Replace Evaporative Emission (EVAP) vent valve Solenoid Assembly and Add/Relocate Filter Box Using Service Kit).
Models : 1999-2007 Chevrolet Silverado (Classic) Models, 1999-2007 GMC Sierra (Classic) Models, 2007-2009 Chevrolet Silverado Models (Excluding Hybrid), 2007-2009 GMC Sierra Models (Excluding Hybrid).
1. Raise the vehicle. Suitably support the vehicle. 
2. Disconnect the EVAP canister vent valve electrical connector.
3. Disconnect the canister pipe from the vent valve.
4. Push in the retainer and take away the present canister vent valve from the fuel tank clip or mounting bracket. Discard the old valve.
5. Reduce the present canister pipe approximately fifty one mm (2 in) to take away the short join end. Crew Cab Brief Field Shown Under, Different Configurations Comparable Prolonged Cab Quick Field Shown Below, Other Configurations Similar Install the brand new canister vent valve to the gasoline tank clip or mounting bracket.
6. Lower bulk 5/eight” heater hose to a size of approximately 76 mm (3 in). Set up the hose between the vent valve and the canister pipe and secure using clamps.
7. Attach bulk 5/8″ heater hose to the vent valve port and safe utilizing a clamp. Run a length as needed alongside the body rail routing to the world above the transmission.
8. Cut the hose to decided size and set up the provided filter box. Safe using a clamp.
9. Secure the filter box to the transmission vent hose just forward of the hose tee*part utilizing a tie strap. DO NOT pinch or limit the transmission vent hose. The filter field opening ought to be pointing downward.
10. Increase the transmission and reinstall the transmission support.
11. Connect the EVAP canister vent valve electrical connector.
12. Tie strap the hose as needed alongside the body rail so as to keep the hose away from pinch factors and warmth sources.
13. Lower the vehicle.
