My 2004 Prius sat for 4 weeks while I rebuilt the battery. After about 2 days of driving the vehicle the check engine light came on. The diagnostic code pulled was a P0446. This is an evap code. While driving the car the scan tool showed the valve opening to 100%. This is with a full tank. Once the vacuum reached -0.5 PSI it would immediately close the valve. The pressure immediately dropped also. When I did fill the tank, the pump repeatedly would shut off. This sounds like a vent solenoid stuck partly open. No other fault codes have been generated so far.
Have you seen this? Does Wisconsin salt its roads? In areas that do that having actual holes somewhere in the evap system is a possibility.
Yes. I have seen this video. I will be doing a smoke test. This should verify any leaks and proper vent valve function. Before ordering a $90 part i want to verify it's bad. My vent valve is very rusty. After 20 years in a salt bath.
