Well, after 213,000KM's (128K miles) on my 2006 AT, I started to get the engine light occasionally. I would clear it using the GM Nano scanner, but it returned after a few days. This can be caused by a faulty or loose gas cap, or from the Evap Solenoid.
DTC P0449
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.

I took the easy route and ordered a new gas cap. Not the issue. I then ordered and received a new replacement aftermarket Evap solenoid from Amazon which included a wiring harness which plugs into the existing GM connector. The GM connector will not fit into the aftermarket solenoid without using the inluded wiring harness.
The solenoid in question is found on the passenger side in a small cavity located between the transmission and gas tank just above the exhaust pipe.
This was not supposed to be difficult as per many threads on the replacement and some You Tube videos.
First off, I raised the rear as high as possible, on jackstands with the right rear tire removed.
With a magnetic flashlight in tow, I crawled under the car, found the solenoid up in the cavity. No issues removing the solenoid from the bracket (rocking side to side and pulling towards the back of the vehicle. Unplugged the eletrical connector. Now, the issues started...The hose clamp is very diffiult to remove due to the tight space to get pliers in there to acess the prongs to get the clamp open enough to slip it down the hose and pull out the solenoid from the end of the hose. Yes, I do have hose clamp plies, both regular and long reach hose pliers. Maybe there is more room to manuever on a manual c6.
Long story short, I could not get the hose off, so I had no choice but to cut it off using pex cutter pliers. There is enough play in the hose to make this happen, but I cut it as close as possible to the solenoid tube. I installed the aftermarket electrical wiring harness to the GM connector using one hand as that is all you can get up there. I pushed the solenoid into the hose, then used a screw type hose clamp so it could be easily removed if ever needed in the future. I got the solenoid back on its bracket, plugged in the electrical connection on the solenoid, then crossed my fingers as I cleared the engine code, Started the car on and off a few times, and the code did not return.
Put the wheel on, removed the jack stands, and took it for a 10 mile run...NO CODE.
All is good again.

 

Definitely not much room up there.I relaced the spring clamp like you so it will make it a little easier if I ever have to do it again.

 

This is another example of the "joy" of owning a Corvette

 

good job...did the same on my 08 Z06 a couple of years ago (yes with the connector harness)...but at only 25,000km!
Mine was from Rockauto. It was supposed to include the harness, but must have been a return from which someone had pilfered the harness. They sent another and now I have a spare evap solenoid
I recall was a bit tight getting in (LS7 has 3" exhaust), but i managed to reuse the OE spring clamp. I'd imagine it was tighter on your automatical, despite smaller exhaust

 

Thanks for your in-depth instructions. Like you I found the area tight to work in, but I was able to get the clip off and then the hose.
Being in New Zealand, the availability of just driving to the auto store and grabbing a replacement part for a Corvette (of any year) is near impossible.
Ok, so to check the EVAP module, I put a ohm meter across the pins and I am getting a high impedance or around 12 meg-ohms, so by this information, it is not an open or short circuit. So is my EVAP module faulty, or there is something else that may be wrong?
What should I see for impedance on the new EVAP module?
Is there a sensor elsewhere that triggers the EVAP module to open/close? Your thoughts please?
Regards, Kevin.