The place and tools are ready for work, we will begin with the back side
CPU plate was demounted
Did you find out Canon EFS 17-85mm F4.0/5.6 IS ?
The subject of our interest
Distance Coding wheel for the E-TTL II flash
Image stabilizer assembly (from the back)
Image stabilizer assembly (from the front lens side)
Front of the focusing lens
USM motor and CPU plate in the pile
What was happened. This is aperture assembly, where aperture blades are jumping (1). Flexible conductor should lead the signals along the stand 3 to the executive device 2, connected to the iris diaphragm 1.
Console for the flexible conductor SHOULD be installed vertically in-between external and internal moving zoom-cylinder, it secures free movement of the flexible conductor loop between cylinders. The console has been inclined (Canon assembly defect) and flexible conductor  was permanently bending  at extremely low radiuses during the zooming. As result-totally broken.