P0446 Scion xB I

DTC P0446 is set if either one of the following conditions applies

1. CCV stuck closed malfunction: The ECM checks for the malfunction by signaling both valves (VSV for EVAP and CCV) to open at a time when the internal fuel tank pressure level is equal to the atmospheric pressure. If the fuel tank develops a highly negative pressure, and it remains in that state for more than 4 seconds, the ECM determines that the CCV is stuck closed. This malfunction is detected regardless of the engine coolant temperature.
2. CCV stuck open malfunction: The ECM checks for the malfunction by signaling the VSV for EVAP to open with the CCV closed to create the negative pressure in the fuel tank. If the fuel tank does not develop an appropriate highly negative pressure, the ECM determines that the CCV is stuck open.