DTC P0449: EVAP Canister Vent Solenoid Valve Control Circuit: Description
WARNING: This page is about a different car, the 2003 GMC Savana and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
An ignition voltage is supplied to the Evaporative (EVAP) canister vent valve. The control module grounds the EVAP canister vent 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 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.