Have elantra GLS 2000 at 95000 miles mil came on with code po446. A mechanic wrote on receipt he replace CCV (charcoal canister valve). The light came ack on but didn't return to mechanic. Now at 120,000 I'm still with po446 CCV stuck closed. I checked the CCV it works. Also checked the solenoid in engine compartment to purge vapor to intake manifold. Does anyone help me. Maybe the fill vent valve on top of gas tank?