2007 GMC/Help please!!

[DaDenaliDude]

That code is telling you that the Vapor Canister Vent Valve is no good or maybe the hose is bad. Did you use OE parts?

This is how you troubleshoot without a Tech2:

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.

I have already replaced that part with an AC Delco part. I will still do the troubleshooting just to make sure it’s not a faulty part. Thanks for your help.

 

[DaDenaliDude]

^^ This, what @swathdiver posted. I would test everything possible before dropping the tank (and I'm not sure this code relates specifically to the lines being plugged). If you can do the electrical test and use the key to turn a test light on and off, that should be enough to tell you if the circuit is good. Then test the same way with the vent valve connected; it should click on and off with the key.

Yes that’s good information. Like I said I’ve replaced that part with a brand new one but I’m still going to do the troubleshooting to make sure it’s not a faulty part.