Where is evap vent valve located on 1996 chevy blazer

It's located under the vehicle back behind the fuel tank , Installed in the canister ! Remove the EVAP canister vent solenoid valve from the canister !
Rotate the EVAP canister vent solenoid valve counterclockwise in order to release it from the locked position.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Disconnect the evaporative emission (EVAP) canister harness electrical connector (2) from the EVAP vent solenoid valve. Clean away any debris that may be present around the EVAP canister vent solenoid valve.
Remove the EVAP canister bolt. Lower the EVAP canister.

P0446 Evaporative Emmission Control System Vent Control Circuit

Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks.

This code could mean one or more of these issues have happened:

Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit

Blockage of vent valve

Bad PCM

Here are some things you can try:

Replace Vent valve

Repair open, short, or resistance problem in control circuit

Repair open, or short, or resistance problem in power circuit

Replace PCM

Codes or no Evap Codes, the issue is in that system
You need a schematic of the evap system, so you can
test the solenoid or valves,mainly the vent solenoid, if that
applies Not the purge valve, that is up front & opens to allow
engine vacuum to draw out fuel fumes from the tank.

your vehicle has a vent valve solenoid located on the evap canister under the back end of the vehicle. You most likely have a bad vaccuum line going to the evap caniser. Have the vehicle smoke tested to verify. If no leaks are found replace the vent valve solenoid

Hi.

P0449 means: evaporative emission (evap) canister vent solenoid valve, incorrect voltage at driver.

Check the evap. ventilation valve, wiring and and solenoid. The evaporative system is located under the vehicle near to the fuel tank.

Regards.

Ginko

The canaster it self is located on the drivers side rear of the wheel near the bumper has three hoses connecting to it 1 goes to the rollover valve on the fuell tank 1 to the canister vent solenoid on the member over the spare tire and the other 1 to the canister purge solenoid located on the mid left side of the intake manifold . What codes do you get ?

the vent hose you are looking for is located off of the gas tank it should be beside your filler hose. if you don't see one there then you tank has a vent on top that is the problen and probably needs replaced

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).

P0446 = Evaporative Emission Control / System Vent Control Circuit Malfunction.

Check it, and before you replace the Evap Canister read this:

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
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This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 02-06-04-037 (Section 06 -- Engine/Propulsion System).
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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.

Correction
After following the Service Manual diagnostic P0446 and determining that the EVAP canister vent valve is the cause of the SES light, replace the existing EVAP canister vent hose assembly with a new assembly, P/N 15086429. This new assembly has an enhanced filtering capability and a filter element that can be easily removed and cleaned. To ensure correct installation, follow the procedure below.

Raise the vehicle. Suitably support the vehicle.
Disconnect the EVAP canister vent valve electrical connector.
Disconnect the vent valve pipe at the EVAP canister.
Remove and retain the EVAP canister vent valve bracket mounting bolt.
Disengage, from the underbody, the two vent valve pipe clips securing the pipe to the underbody.
Remove and discard the complete EVAP canister vent hose assembly.
Position and secure the new assembly to the underbody using the existing hole and mounting bolt.
Tighten
Tighten the bracket mounting bolt to 12 N·m (106 lb in).

Install the two vent valve pipe clips into the existing underbody holes.
Connect the vent valve pipe to the EVAP canister.
Connect the EVAP canister vent valve electrical connector.
Lower the vehicle.
When properly installed, the new EVAP canister vent hose assembly will be positioned outboard of the original installation location. This new location provides clearance for accessing the filter element for cleaning purposes. To access the filter element, disengage the filter cover to valve locking finger by gently lifting the finger upward while simultaneously rotating the filter body clockwise. After approximately 45 degrees of rotation, the filter can be disengaged from the valve by gently pulling outward. The filter cover can then be removed and the filter element and body can be washed with soap and water. Prior to reinstalling, ensure that the body and filter element are dry.

Parts Information
Part Number 15086429 Hose Asm-Evap Emis Cnstr Vent

Hope help with this.

you will have to replace the evap vent valve for the emisions system usually located at the charcoal canister under the vehicle near the fuel tank.