N62 Intake manifold & motor in spec?

[WMSBOSS]

With permanent fault codes 2B71 and 2B72 I removed and disassembled the manifold & motor to better understand what might be a cause of failures. I do understand the manifold is not intended to be serviced, but I was curious. After disassembly I found the drum had significant carbon deposits causing too much friction for it to spin easily. I thought I found the issue. After thoroughly cleaning the entire assembly I reassembled carefully making sure to reseal. Although there was still a rubbing sound it had been greatly reduced.
The motor tested at 2.8 ohm (spec 2-8 ohm) and actuated quickly and positively with 12 V applied. I felt good with my repair.
The engine was loaded with carbon and needed valve seals amongst other things, so I pulled it to do a complete re-fresh. Upon restart I found I had the same faults. After researching I found that max voltage supplied to the motor from the dme is 5v and often with less. I made a big mistake by assuming it was 12v. When I applied 5v to the motor (mounted on the intake) it rotated the barrel, but very slowly, and pulling higher amps then I thought it should. Bench testing the motor went better obviously without load and seemed fine. Curious, I removed the throttle body and tried to spin the barrel with my fingers, barely could move it, but with a little help from a ratchet it moved with little effort.
With that long back story, my questions are simple.
1- What is the minimum voltage required to actuate the drum?
2- Is my assessment of the motor correct that it tests within spec?
Thanks for reading and leaving any words of wisdom.

[Timm]

Never had to pull it apart - but I would guess that there must be some kind of feedback to signal the error codes - is there a sensor built into the motor assembly? Or, is the feedback the current taken by the motor as is used in some other systems?