Code p0449 vent solenoid intermittent

https://www.youtube.com/watch?v=34WJXJMNtfY https://www.youtube.com/watch?v=PErhl_mIwGA

it may not just be the vent need to check the circuit and lines P0449 Chevrolet Evaporative Emission Vent Valve Solenoid Malfunction P0449 Evaporative Emission Control System Vent Valve Solenoid Circuit... EVAP Code P0449

DTC P0449 Evaporative Emission (EVAP) Vent Solenoid Control Circuit.
Circuit Description
An ignition voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.

Do you know how to test automotive electrical circuits using a volt meter ? How to test a transistor (driver) inside the PCM . Videos on youtube. Do you know what a wiring diagram is ?
Also search P0449 on youtube . Free wiring diagrams here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine size . Under system click engine ,then under subsystem click fuel controls . Click search the blue link. Scroll down to #9 diagram . Circuit for vent solenoid . This video is a chevy truck ,doesn't matter .
GMC Chevy Truck DTC P0449 EVAP Vent Solenoid Control Circuit

DTC P0449: Evaporative Emission (EVAP) Vent Solenoid Control Circuit , your vent solenoid is opened or the wiring circuit is . The vent solenoid is by the charcoal canister at the gas tank .
P0449 Battery voltage is supplied to the EVAP canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver.

Code 449 is for a defective vent valve solenoid. The engine computer can not open or close the valve or can not tell if the valve is operating.
The valve/solenoid would need to be tested and you will probably need a shop manual to get the testing procedure.

Code 449 is for a problem with the EVAP system vent valve solenoid circuit.
The solenoid may not be reacting to computer commands to open or close.
The solenoid and circuit would need to be tested.

P0449 is the evap vent valve solenoid circuit malfuntion.
P0455 is an evap gross leak
Perhaps the gross leak code has to do with the vent valve. Find the vent valve. It should be near a rectangle evap canister. Maybe under the bed. The small vent line from the fuel tank will go to it. The solenoid is near the cansiter. With the key off the valve will be open. With the key on it should be closed. You may try disconnection the hose and blow through it with both key off and on and see if air will pass through. If the valve has died and is stuck open, that can be the huge leak.

If it is not the leak then a smoke machine should be used. Easier than searching the lines for bad o-rings, splits, or whatevers.

There may be an emissions leak but a very common issue is the canister vent valve. Make sure if you contact your local dealership that you have your vehicles vin number available.

P0449 - Evaporative Emission (EVAP) Vent Solenoid Control Circuit

P0455 - Evaporative Emission (EVAP) System Leak Detected

P0449....Evaporative Emission Control System Vent Valve/Solenoid Circuit could be the engine breather

Hello. Your code indicates that your emission system is acting up. If you live in California, you might have a problem passing the next mandatory emmissions test. The PCM has determined that a malfunction exists in the electrical circuit for the vent valve/solenoid in the evaporative emission control system.

Definition:
EVAP (Evaporative Emission System) purge/vent solenoid circuit condition

Explanation:
The solenoids and system wiring are monitored for opens or shorts

Probable Causes
1- Purge or vent solenoids defective
2- Check connector and wiring
3- fuel, saturated vapor canister
4- Failed EVAP vent solenoid