2007 avalanche code p0449

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SUMTOY2

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Ok I need help we have the engine code P0449 and we replace the purge canister evap syllonyd and canister But the check engine light and code keeps coming back on 2 different solenoid now!
What else could be causing this code to come back?
 

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P0449 relates to the Vent Valve (or possibly the vent valve circuit) that is connected to the canister. The purge valve you replaced, if I'm reading your post correctly, is the one on the engine. I believe there is an updated vent valve that has a longer hose to install it up and away from the dirt, so that may need to be replaced. A bidirectional scanner could be used to test the control.
 
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SUMTOY2

SUMTOY2

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P0449 relates to the Vent Valve (or possibly the vent valve circuit) that is connected to the canister. The purge valve you replaced, if I'm reading your post correctly, is the one on the engine. I believe there is an updated vent valve that has a longer hose to install it up and away from the dirt, so that may need to be replaced. A bidirectional scanner could be used to test the control.
We replaced the evap canister and purge valve solenoid back by the tank.
 

swathdiver

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Ok I need help we have the engine code P0449 and we replace the purge canister evap syllonyd and canister But the check engine light and code keeps coming back on 2 different solenoid now!
What else could be causing this code to come back?
From the shop manual:

P0449
1. Ignition ON, engine OFF, command the EVAP vent solenoid ON and OFF with a scan tool.
2. Listen for a click when the valve operates. Verify that both the ON, and the OFF states are commanded.
3. 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

1. Ignition OFF, disconnect the harness connector at the EVAP canister purge or vent solenoid valve.
2. 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.
3. Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
4. 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.
5. If all circuits test normal, replace the appropriate solenoid valve.

Don't forget, often times new parts are no good, especially aftermarket.
 
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SUMTOY2

SUMTOY2

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Thanks for the help everybody will try these things when I get home from work tonight
 

Fless

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You can test the vent valve itself by blowing low pressure air -- like with your mouth -- through it, while applying 12vDC intermittently to the electrical terminals. The vent should be open with no voltage applied, and closed when B+ is applied.
 
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SUMTOY2

SUMTOY2

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THAKS FOR THE HELP EVERYONE, ALL IS GOOD PASSED EMMISIONS TODAY!
 

Fjs0001

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I replaced my Vent Valve Solenoid two or three years ago. I took it out for a drive 2 weeks ago after it sat for 3 months and I got the gas cap alarm and a P0455 code. I retightened the gas cap and cleared the code. No codes for a few days and today I drove it to work. I started it on my lunch break and I got a P0449 code as soon as I started it. Is the P0449 code related to the purge valve on the motor? I keep reading conflicting information in old posts.
 

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