Do you want to avoid warranty go ahead.
I avoid mine almost 3 days after I get my gear. I have special needs. I test it when I get it and if its DOA I send it back at my charge. If it works, some times it will sit on my shelf for 6 mths, Like a spare.
I always buy a spare motor. Its just makes these problems way less hassle. I can test if I have a DOA hub or controller.
I would ask the warranty officer permission to investigate the failure under his instructions and provide photos.
I would offer to make my own repairs for hall failure.
I would only expect a return if the windings were broken on arrival.
In this case I would offer to pay for the return and ask to keep it instead for parts. I would want my replacement hub sent and delivery paid by GM.
But that's meeeee
LOL
However warranty is a hard ask over a couple of hall sensors. But it not cost effective.
First thing.
Before you do anything, are you sure the controller is working?
We have tested the hall sensors, and we are absolutely sure there is a failure?
We get the two beeps indicating this. Right?
And!
Its connected properly?
So we can gather if we lock the freewheel we will not need hall sensors to operate your motor.
This can be a liberating experience. Providing the windings are sound you will never have motor failure again.
Count on this part to live a long time and don't overload or overvolt more than 40v.
Once this mod is done anything else is one part easier to get going,
You have a good battery and possibly a good controller.
Good luck if you proceed. and god speed.
Edit:
I believe your might be the first to do this on a GM mini motor and GM controller combination. So you're the man.
How are you going to do it?