- Missing Fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- Vent control valve harness is open or shorted
- Vent control valve circuit poor electrical connection
- Faulty vent control valve

There are factory service bulletin for the following Toyota models:


Toyota RAV4
Toyota Tercel
Toyota Paseo
Toyota Camry
Toyota Avalon
Toyota Tacoma
Toyota 4Runner
Toyota T-100


Toyota Factory Service Bulletin OBDII Code P0446


2003 – 2004 Toyota Corolla
2003 – 2005 Toyota Matrix


Toyota Factory Service Bulletin OBDII Code P0446 Corolla and Matrix

The P0446 codes triggered when an improper voltage signal is sent to Engine Control Module (ECM) through EVAP canister vent control valve.

- Engine Light ON (or Service Engine Soon Warning Light)
- Possible a noticeable fuel odor caused by the release of fuel vapors

The Evaporative System (EVAP) canister vent control valve is located on the EVAP canister and is used to seal the canister vent.


This solenoid valve responds to signals from the Engine Control Module (ECM). When the ECM sends an ON signal, the coil in the solenoid valve is energized. A plunger will then move to seal the canister vent. The ability to seal the vent is necessary for the on board diagnosis of other evaporative emission control system components.


This solenoid valve is used only for diagnosis, and usually remains opened.

More Bulletins