System Description
WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge diagnostic monitors the changes in the vacuum pressure in the fuel tank. The powertrain control module (PCM) will command the EVAP vent valve ON, CLOSED, and the vacuum pressure switching valve ON, OPEN, with the engine running. This allows engine vacuum into the entire EVAP system. The PCM continues to operate the purge valve until the vacuum has reached a specified limit, at which time the PCM commands the purge valve OFF, CLOSED. If the PCM detects the vacuum level was not achieved, or the vacuum level increased beyond the specified limit, a DTC P0441 will set.