DTC P0449: EVAP Canister Vent Solenoid Control Circuit: Description
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
An ignition voltage is supplied directly to Evaporative (EVAP) emission canister vent valve. Powertrain Control Module (PCM) controls EVAP vent valve by grounding control circuit via an internal switch called a driver. Primary function of the driver is to supply ground for the controlled component. The PCM monitors driver status. If PCM detects an incorrect voltage for commanded state of the driver, DTC P0449 will set.