Possible causes – Low transmission fluid level– Dirty transmission fluid– Faulty pressure control solenoid valve ‘C’– Pressure control solenoid valve ‘C’ harness is open or shorted– Pressure control solenoid valve ‘C’ circuit poor electrcial connection Tech description There is a factory service bulletin for the 2004 Toyota Sienna2004 Toyota Sienna Factory Service Bulletin OBDII Code…