i have a 2006 gmc truck engine light stays on . i pulled the code is , evaporative emission control system vent valve / solenoid circuit malfunction. what is this ? where is it ? how to check it? thank you ..

It is under the truck by the fuel tank. Usually attached to the charcoal canister. The valve is always opened. When power and ground are applied to it the valve closes. so if you blow though it while applying power and ground it should close. These fail intermittedly from dirt. Common evap failure on this model.

Jeff