DTC P0446: EVAP Vent Valve Performance: Description

A restricted or blocked Evaporative (EVAP) emission vent path is detected by the control module monitoring the Fuel Tank Pressure (FTP) during normal operation. The control module commands the Evaporative (EVAP) emission vent valve OFF (open), and the EVAP canister purge valve ON (open). The fuel tank pressure should remain low as vacuum is drawn on the EVAP system. If the vent path is blocked or restricted, the vacuum level will increase and DTC P0446 will set.