This is a WaterWall deflector error, and it occurs when the WaterWall deflector is blocked. This can happen when parts are not attached properly or there is an object blocking it.
Check the deflector. If it is not block and the vane is clipped well, most likely, the vane motor is not working or the motor sensor is faulty. Listen to the motor: if it sounds like it usually does, and a check has not revealed any problems, replace the sensor.