Picture of location of canister purge valve on 2008 chevy avalanche 5.3 liter v8 engine

Chevy V8 evap canister PURGE valve solenoid is located top engine and bolts directly into the intake manifold. It has 1 electrical cable and 1 vacuum line.

DTC P0449: Evaporative Emission (EVAP) Vent Solenoid Control Circuit

Circuit/System Description
An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM) grounds the EVAP canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.
Battery voltage is supplied to the EVAP canister solenoid valve. The ECM grounds the EVAP canister vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP canister vent solenoid valve as ON or OFF.

P0449
Ignition ON, engine OFF, command the EVAP vent solenoid ON and OFF with a scan tool.
Listen for a click when the valve operates. Verify that both the ON, and the OFF states are commanded.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing
Ignition OFF, disconnect the harness connector at the EVAP canister purge or vent solenoid valve.
Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A and ground.
? If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister purge solenoid.
Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
Command the EVAP canister purge solenoid valve to 50 percent with a scan tool, or the EVAP canister vent solenoid valve ON and OFF. The test lamp should respond to the command.
? If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
? If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits test normal, replace the appropriate solenoid valve.

This is how to test electrical circuit for the vent solenoid .

Try 2008 Chevrolet Avalanche canister purge valve location Google Search

look here: https://www.google.com/search?q=98+grand+voyager+relay+box&biw=1536&bih=770&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjTm_z3tMzQAhUT92MKHeHSBxEQsAQIQA#tbm=isch&q=canister+perg+valve+switch+on+a+4.3+liter

under truck next to gas tank valve attached to canister

Canister or the solenoid to run it?

Your dealership service department has a book on the vehicle that they will let you copy a page from.

Some might have an ses p0446, evap emissions vent circuit low. If you take it to the dealer they want 300-400.00 to fix the problem. GM has a service bulletin on this condition and have the updated part for 180.00, thats suppose to eliminate this issue.

Basically the problem is, the evap purge vent valve gets clogged with dirt, especially if the truck is used in dirty conditions. Well I figured there had to be a cheaper way to cure this problem.

Here it is:
1) find the location of the vent valve; its under the truck, locate the charcoal canister on the front of the gas tank and trace the vent line to the vent valve.
2) Take the bracket loose with a 5/8 wrench.
3) Spin the valve around so the side with the hole is facing you.
4) Take an air compressor and blow the vent valve out.
5) reinstall and clear the code and it's fixed.

Now I know the updated part from gm is supposed to keep the valve from clogging ever again, but why spend the money when all you have to do is blow out the vent valve every 50k-100kmi and save your $$$!

Subject: DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Service Engine Soon (SES) Lamp Illuminated (Replace Hose/Evaporative Emission (EVAP) Canister Vent Asm) #02-06-04-037A - (02/02/2005)
Models:
- 1999-2003 Chevrolet Silverado Models
- 1999-2003 GMC Sierra Models
--------------------------------------------------------------------------------
This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 02-06-04-037 (Section 06 -- Engine/Propulsion System).
--------------------------------------------------------------------------------
Condition
Some customers whose vehicles are operated in dusty type environments, such as farming or mining off-road type applications, may comment about the illumination of the instrument panel SES light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.

Cause
Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.

Part Number 15086429 Hose Asm-Evap Emis Cnstr Vent


Removal & Installation
Purge Solenoid Valve-2.2L (L61) Engine

1. Disconnect the evaporative emission (EVAP) canister purge valve harness connector.
2. Disconnect the vacuum pipe from the EVAP canister purge valve.
3. Disconnect the purge pipe from the EVAP canister purge valve.
4. Remove the EVAP canister purge valve and bracket.
5. Remove the EVAP canister purge valve from the purge bracket.
6. Inspect for carbon release in the EVAP canister purge valve ports.
   

To install:

1. Install the EVAP canister purge valve on to the purge bracket.
2. Install the EVAP canister purge valve and bracket. Tighten the purge bracket nut to 71 inch lbs. (8 Nm).
3. Connect the purge pipe to the EVAP canister purge valve.
4. Connect the vacuum pipe to the EVAP canister purge valve.
5. Connect the EVAP canister purge valve harness connector.
6. Remove the air cleaner outlet resonator.
7. Disconnect the EVAP canister purge valve harness connector.
8. Disconnect the engine purge pipe from the EVAP canister purge valve.
9. Disconnect the engine vacuum pipe from the EVAP canister purge valve.
10. Remove the EVAP canister purge valve mounting bracket attaching bolt.
11. Remove the EVAP canister purge valve along with the mounting bracket.
12. Installation is the reverse of the removal procedure. Tighten the bracket bolts to 71 inch lbs. (8 Nm).

Purge Solenoid Valve-2.4L Engines

1. Remove the front purge pipe from the evaporative emission (EVAP) canister purge valve.
2. Remove the rear purge pipe from the EVAP canister purge valve.
   NOTE The EVAP canister may have released carbon particles, which caused this part to fail, and may cause damage to other components. Check the EVAP canister for loose carbon before returning the vehicle to service.
   
3. Disconnect the EVAP canister purge valve electrical connector.
4. Insert a screwdriver between the EVAP canister purge valve and the mounting bracket in order to release the lock tab.
5. Remove the EVAP canister purge valve mounting bracket attaching nut, if replacing the bracket.
6. Remove the bracket.
   

To install:

1. Install the mounting bracket and the attaching nut for the EVAP canister purge valve. Tighten the nut to 71 inch lbs. (8 Nm).
2. Slide the EVAP canister purge valve onto the mounting bracket. Make sure the lock tab locks the valve in place.
3. Connect the EVAP canister purge valve electrical connector.
4. Connect the rear purge pipe to the EVAP canister purge valve.
5. Connect the front purge pipe to the EVAP canister purge valve.

Vent Solenoid Valve-2.2L & 2.4L Engines

1. Raise the vehicle
2. Loosen the EVAP canister vent valve hose clamp and slide the clamp down the hose away from the EVAP vent valve hose connection.
3. Remove the hose from the EVAP canister vent valve.
4. Remove the EVAP canister vent valve by placing a pry bar between the valve and mounting surface, and moving the valve forward.
5. Remove the clip from the EVAP canister vent valve harness connector
6. Disconnect the EVAP canister vent valve harness connector.
   

To install:

1. Connect the EVAP canister vent valve harness connector
2. Install the clip into the EVAP canister vent valve harness connector.
3. Install the EVAP canister vent valve by pushing the mounts into the original holes.
4. Lubricate the hose end with lubricant.
5. Install the hose to the EVAP canister vent valve.
6. Slide the EVAP canister vent valve hose clamp down on to the hose connection at the EVAP canister vent valve.
7. Lower the vehicle.

Hope this help (remember commetn and rated this).

The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid and the EVAP canister. The service port is identified by a green colored cap.



Fig. Showing location of (1) Evaporative Emissions (EVAP) Canister Purge Solenoid and (2) Exhaust Gas Recirculation (EGR) Valve




Fig. EVAP Purge valve solenoid (3) mounting bolt (2) and insulator (1) on 2000-2005 4.8L, 5.3L, 6.0L Engines

Hope this help (remember rated the post).

5.3 liters V8 front engine with 96 mm bore, 92 mm stroke, 9.5 compression ratio, overhead valve and two valves per cylinder LM7