Another Power Steering Question

[Rusty]

I have a 2001 ES300 with 205K miles. A few days ago the steering started getting stiff when I take a turn. It feels like someone is pushing/pulling back on the steering when I make a turn.

I checked the fluid, did the left/right lock to lock thing, checked for equal tire pressure and checked that the lugnuts were tight, but none of that helped.

I would like to exhaust all the easy/obvious fixes before bring it to a mechanic. Is there anything else I can do to try and isolate the problem? Is there a screen in the ES300 system like there is in the LS400's?

Any advice you can give is appreciated.

Thanks.