You could remove return hose [low pressure ] the one with a clip on .The high pressure is a high pressure nut fixing . Put it in a good size jar switch on , start up if its working it will pump oil in to the bottle or container. If no PAS oil then could be the pump or the steering rack .Then you need to dig deeper like a pas check at a garage.The pump is no big job to remove and check on the bench ,and seals can put it right .Or send it away to have it rebuilt ,if you dont think you can do it.The pump is self bleed, thats when you fix it back in .The rack is not easy to fix as you need special tools to set them up .Pressure is checked after assembly ,these parts are a danger if not done right.