Just went through this with my 2002. The first easy check is fluid. Open the Allen screw towards top of the oil reservoir and add fluid til it comes out the opening. Long story short everyone I talked to said don’t bother rebuilding or try to fix it,not worth it. I wish I would have just took there advice. I put about $50 in parts trying to fix it to no avail. Mine was doing same thing as yours and after trouble shooting I figured there was a bad check valve in the pump so I replaced all the valves and seats but still did not work. In the end I ended up buying a whole new trim assembly. $800 ouch. Wish I had a good answer but I would suggest you do what everyone told me and just bite the bullet.