Okay I successfully reset the pinch protection on a IS300 today. So I thought I would share the highlights of the procedure.
Removing the assembly is actually quite easy. I found it easier than replacing the mabuchi motors in the door lock assembly. You do NOT have to remove the speaker that is riveted in.
Once you have removed the 6 bolts mounting the rails & motor and the 2 bolts mounting the window to the rails, you can remove the assembly. You will fold the rails together and pull the assembly out of the large access hole. Don't forget to disconnect the electrical harness.
I followed the youtube instructions here
For the IS300 - here's the differences.
* I followed the reset procedure in the video - wind the motor upwards for 4 seconds.
* There is no spring on the IS300 rail assembly. Skip this portion.
* you must clock (orient) the rail assembly in the down position. Not in the middle like in the video. If you're wondering what the down position is - you can mock it up against the door to be sure.
* Now you must mate the motor to the first tooth in the gear. Install the 3 torx bolts.
* Reinstall the assembly in the door. WARNING: You must orient the short rail (top most rail) with the U-shaped end towards the right. The flat side goes to the left. This is important because it determines the travel of the rail assembly. If you orient it backwards the window will not travel completely upwards.
* When reinstalling the window, you can only install one mounting bolt (left most) The other one doesn't have enough clearance to insert. I installed that the second bolt after finishing the reset procedure.
* Like the video, roll the window up and down 3 times. Then verify auto-up works properly without triggering pinch protection.
* Move the window down to align with the access hole for the 2nd bolt. Install the second bolt.
Good luck! It was easier than the door lock motor replacement (less time) once I figured out the rail orientation.