PO 449 Evaporotive Emissions Vent Valve Solenoid

DTC P0446: Evaporative Emissions (EVAP) Vent System Performance
Circuit/System Description
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inch H2O in a calibrated time, this DTC sets.
Diagnostic Aids
?€¢
An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem.

?€¢
An EVAP canister, vent hose, or vent solenoid valve that has restricted flow may cause this DTC to set. Using a purge solenoid command with a scan tool will allow vacuum to be applied to the system instead of pressure. With the engine running, the EVAP canister vent solenoid valve open, and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than 5 inches H2O.

?€¢
An EVAP canister filter that is restricted can cause this DTC to set. Refer to Evaporative Emission Canister Replacement .

?€¢
Disconnecting one component at a time while the EVAP system is under flow will help to pinpoint a restriction in the system

Do you have a scan tool that reads data PID'S ?
Your FTP - fuel tank pressure sensor could be at fault !

Ignition ON and fuel cap removed, verify that the FTP sensor parameter is between 1.3-1.7 volts. ?‡'
If not within the specified range, go to the FTP sensor section in Circuit/System Testing.

1. Install the fuel cap.
2. With the engine running, the EVAP canister vent solenoid valve open, and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than 12 inches H2O.

?‡'
If the fuel tank vacuum is greater than the specified range, go to the restriction section in Circuit/System Testing.

If

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.

Trouble Code: P0446

Evaporative Emissions (EVAP) Vent System Performance

Possible Causes:


The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill condition.An EVAP canister, vent hose, or vent solenoid valve that has restricted flow may cause this DTC to set. Using a purge solenoid command with a scan tool will allow vacuum to be applied to the system instead of pressure. With the engine running, the EVAP canister vent solenoid valve open and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than 5 inches H2O.An EVAP canister filter that is restricted can cause this DTC to set. Refer to Evaporative Emission (EVAP) Canister Filter Replacement and Evaporative Emission (EVAP) System Cleaning .Disconnecting one component at a time while the EVAP system is under flow will help to pinpoint a restriction in the system.Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.For intermittent conditions, refer to Intermittent Conditions .

PO 443--Evap Purge Control Valve Circuit

PO 449---Same thing---Vent Valve/Solenoid
Circuit Malfunction

This is for a defective Evaporator vent valve solenoid. It should be close to the canister on most cars, but your car is configured for high water crossings so it may be mounted higher.

You can probably buy one at Autozone,or another aftermarket parts store. There is usually very little to changing one of these.

DTC P0449 - Evaporative Emission Control System Vent Valve/ Solenoid Circuit Malfunction
The most likely problem is the evap vent solenoid which is mounted under the truck back by the fuel tank. The code is related to the circuit to the solenoid. Most likely the solenoid is shorted or Open which is causing the code to set. The other things to check if the solenoid is not the problem is the wiring to the solenoid could be corroded or broken or damaged. The last thing to suspect is the pcm which is the computer that runs the system. It could have a faulty driver inside, but I would suspect the solenoid or wiring first.

There is a bulletin for the vent solenoids getting dirt or road debris inside of them so when you go to get your solenoid, you may get a kit that will require you to relocate the solenoid and add a section of heater hose and a new inlet which you will need to mount around the passenger side of the trans. This keeps road debris and dirt from getting into the solenoid.

Check Diagnostis Information Procedure.

Hope this helps and just keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa.

DTC P0449 - Evaporative Emission Control System Vent Valve/ Solenoid Circuit Malfunction
The most likely problem is the evap vent solenoid which is mounted under the truck back by the fuel tank. The code is related to the circuit to the solenoid. Most likely the solenoid is shorted or Open which is causing the code to set. The other things to check if the solenoid is not the problem is the wiring to the solenoid could be corroded or broken or damaged. The last thing to suspect is the pcm which is the computer that runs the system. It could have a faulty driver inside, but I would suspect the solenoid or wiring first.

There is a bulletin for the vent solenoids getting dirt or road debris inside of them so when you go to get your solenoid, you may get a kit that will require you to relocate the solenoid and add a section of heater hose and a new inlet which you will need to mount around the passenger side of the trans. This keeps road debris and dirt from getting into the solenoid.

Check Diagnostis Information Procedure.

Hope this helps and just keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa.

P0442 - Evaporative Emissions System Leak Detected (Small Leak)

P0455 - Evaporative Emissions System Leak Detected (Gross Leak)

This diagnosis detects leaks in the EVAP purge line using engine intake manifold vacuum. If pressure does not increase, the ECM will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve under the following vacuum test condition. The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this depressurization is implemented, the EVAP canister purge volume control solenoid valve will be closed.

Causes:
- Missing Fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- Incorrect fuel tank vacuum relief valve
- Leak is in line between intake manifold

Solutions:
- Re-tighten or replace fuel tank filler cap
- Replace damaged or leaking EVAP canister
- Replace damaged or leaking lines.

your evap vent filter is plugged. you can find it in front of the gas tank underneath. blow it out and it will be fine.

Check all vacuum lines from the gas tank to the evaporative charcoal cannister by the gas tank and to the purge valve located at the engine. Check the electrical connector at the vent solenoid which should be located on the charcoal cannister and purge valve solenoid by the intake manifold.