All I can say is that the same thing has happened to me.
Once the Hall Sensor on the Mini-motor's go, you're going to need a new motor. Since it has a freewheel in it, you can't use sensorless control on it, so until you get a replacement one, the motor will NOT run.
I was one of the unfortunate ones that this happened to, IMMEDIATELY after the "warranty" has run out, so basically I'm out $300+ and a motor...
I'm having someone TRY to make the freewheel mechanism lock, and IF it can be done, It'll cost me ANOTHER $125 just to get it "fixed"
Good luck, my Friend.
Here is a quote from another post that I added to...
They are selling an inferior product, and when it breaks, they wait until it's out of warranty to talk to you and then say, sorry... you're screwed after spending $300 on a useless piece of crap, that we should have warned you about, instead of just trying to screw ya, but the Mini-motors have too many problems and have been known to break very easily and if your hall sensors go, you're screwed too, and have to have someone fix the mini-motor, to turn it into a NON freewheeling item, and after you've spent the $75 to $100 to have someone do that for you, you now are smart enough to ever buy another GM product again.
My .02 (and my experience with GM China)
(Oh and forget the fact, that i've had FOUR of the "magic controllers" fail on me. (which they've replaced after much BlTCHING by me)