Error Code P0449-00 On 2008 Tahoe

[EddieC]

This error code comes back almost immediately after erasing so it's persistent.
The code reader notes "Evap Vent" and then "Solenoid Control Circuit" then "Short to Ground-Fail" and "Open Test - Fail".
Any opinions if that points more at the wiring or to the solenoid?

I went through this kind of thing with what seemed to be an oxygen sensor issue only to find out, after springing for sensors (one at a time) that is was none and just a wire fractured inside the insulation so I thought I'd get opinions before going all in with the Evap Vent issue.

Searching for video got a bit of confusion; is the solenoid on top of the engine or down below in the rear?

 

[Fless]

The vent solenoid is in the rear of the SUV. The purge valve is on the engine.

Generally speaking a circuit code like this points to a faulty vent valve, with the electrical "circuit" failure inside the valve itself, which is most common. But there can also be an issue with the actual wiring, so you may want to test the circuit by replacing the valve with a, say, 1A test light and using a scan tool to actuate the circuit. That verifies electrical control from the ECM to the valve connector.

You can bench test the valve by removing the electrical connector and trying to blow through it while using an external 12v DC power supply or battery feed to switch the power on and off. Polarity doesn't matter. With no power applied you should be able to blow through it; with power applied it should click and you should not be able to blow through it. Cycle the power to determine if the solenoid is intermittent.

 

[swathdiver]

It's almost always the vent for that code and rarely the wiring or ECM.

 

[EddieC]

Thanks guys

 

[EddieC]

BiPolar truck.
Started up today, no light and it hasn't come back on.

 

[EddieC]

I swapped out the vapor canister purge valve solenoid (atop engine) about three weeks ago after a code reset and all seemed good with no code until today when the P0449 code came back.