Possible causes

– 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

Tech notes

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