Scanner is making a grinding noise and won't scan.

check the continuty in scanner cable to cis unit and check the continuity 2ends off scanner cable.
1.cable problem
2cis problem

The Grinding Noise has something to do with the scanner not the Printing Part, I think the scanner could have something stuck on the moving tray....!!!!!!

You may find the answer to your streaking issue here.

Normally Canon scanners work well for long time, Change the pickup rollers for every 250,000 pages and check other rollers for every 500,000 pages. In case you have been scanning documents with quite a good amount of dust, you may need to check at an earlier interval. Replace any worn out roller. Check if the small bearings at the end of each roller is perfect. Clean thoroughly all the rollers, dont use solvents. S. Mohan, Chenna, India

poss nylon gears maybe time for a new one

Try cleaning the guide bar that the scanning head rides on, apply a thin film of lithium grease on the guide bar

The most common problem is that the pulley breaks, you might be able to see it through the glass. looks where the belt goes, and see if the pulley is broken.

also, some people forget to unlock the locking mechanism when the unit gets moved, the locking switch is on the side.

Please open and apply oil on roller rod as some rust have accumulated on it prohibiting it move.

take a look on the underside of the scanner. there may be a switch that goes from lock to unlock. try to move it to lock and back into unlock. this lock is usually used to lock the bar from moving during shipping. if this got moved back to lock or bumped while you had it turned over, the scanner will not allow the bar to move.. try this first.