From my experience, there is a broken gear on the paper tray Feed Head that must be replaced. So you need a tech for replacing those gears.
Sounds like you have tried everything already, so it would be a hardware escalation: 1-800-821-2797 or 1-800-835-6100.
I have a lift error problem in tray 1 and 2.
I have swapped the paper cassettes in the trays - the error remains with the trays.
When I touch the sensors in the back, the motor for the lift also starts. This happens with every tray.
In tray 1 and 2 the motor tries unsuccessfully to lift the paper.
When I change the trays, they work (in tray 3).
If I insert the cassette from tray 3 into 1 and 2, it does not work again.
The wheels all look good, in tray 3 the cassettes from tray 1 and 2 also work.
Anyone have any advice for me? Thanks a lot!