Code P0446 indicates a "Evaporative Emission Control System Vent Valve Stuck Closed". This means the vent valve, which allows fuel vapors from the fuel tank to be released to the atmosphere, is not opening properly.
Code P0441 indicates a "Evaporative Emission Control System Incorrect Purge Flow". This means the purge valve, which allows the engine to draw in fuel vapors from the fuel tank, is not functioning correctly.
Here's how to troubleshoot and potentially repair these codes:
1. Check the EVAP System Components:
* Vent Valve: Locate the vent valve (typically near the fuel tank or charcoal canister). Test it by applying vacuum to the valve using a vacuum pump or hand-held vacuum. If it does not open properly, replace the valve.
* Purge Valve: Locate the purge valve (typically near the intake manifold). Test it by applying vacuum to the valve using a vacuum pump or hand-held vacuum. If it does not open properly, replace the valve.
* Charcoal Canister: Inspect the charcoal canister (typically mounted near the fuel tank) for any signs of damage or leaks. If it's damaged, replace it.
* Vacuum Lines: Check all vacuum lines connected to the EVAP system for cracks, leaks, or disconnections. Repair or replace any damaged lines.
2. Check for Fuel Tank Pressure:
* With the engine off, apply a vacuum to the fuel tank using a vacuum pump.
* Monitor the vacuum gauge for any leaks in the system.
* If the pressure drops significantly, there's a leak in the fuel tank or its connections.
3. Inspect the Fuel Tank Cap:
* Check the fuel tank cap for any signs of damage or cracks.
* Ensure the cap is securely tightened.
* A faulty fuel tank cap can cause the EVAP system to malfunction.
4. Consider Other Potential Issues:
* Fuel Tank Vent Hose: Check the vent hose for any blockage or leaks.
* Fuel Pump: A faulty fuel pump can sometimes affect the EVAP system.
* Wiring and Connectors: Inspect wiring and connectors related to the EVAP system for any signs of damage or corrosion.
5. Clear the Codes and Retest:
* Once you have addressed any issues, clear the codes using an OBD-II scanner.
* Start the engine and drive the vehicle for a few days to see if the codes return.
Additional Tips:
* Consult your vehicle's repair manual for specific instructions and diagrams related to the EVAP system on your 1998 Toyota Corolla VE.
* If you're not comfortable working on your vehicle's EVAP system, consult a qualified mechanic.
Remember: This is a general guide and your specific repair steps may vary depending on the exact problem. Always refer to your vehicle's repair manual or consult a qualified mechanic for specific guidance.
