Toyota Sienna Trouble Code P0441 - Evaporative Emission Control System Incorrect Purge Flow. Your Toyota Sienna is equipped with an EVAP system designed to capture and route gasoline vapors to the intake manifold. Trouble code P0441 indicates a problem with the EVAP system's purge (gasoline vapor) flow; purge flow is lower or higher than it should be. The purge flow is controlled by the SVS (vacuum switching valve), purge valve and vent valve (both vacuum operated). The EVAP system has a pressure sensor which is used to detect if the EVAP system, which includes the gas tank, charcoal canister, SVS system and all hoses and solenoids, are functioning properly.
The probable faults to look for include:
1.) Defective purge or vent valve(s)
2.) Disconnect or damaged SVS wiring
3.) Fuel saturated EVAP canister
4.) Defective or damaged EVAP canister or VSV (vacuum switching valve) solenoid
5.) Broken, brittle, disconnected vapor hose(s)
To start we recommend you check all hoses to and from the charcoal canister and VSV system (located and attached to the EVAP canister). The EVAP canister, along with vent/purge and SVS system is located near the rear axle of your Sienna and underneath a black plastic shroud. Testing the SVS can be done by applying battery voltage to the SVS solenoid and checking to see if it holds vacuum. You should hear a clicking noise as this happens and if applying vacuum to the valve, notice vacuum being released when energized. The SVS should be fully closed when no voltage is being applied. If the valve is leaking it must be replaced. Should you choose to replace the charcoal canister it will be equipped with a new pressure sensors and SVS.