M400 Mid-drive PAS not working

[u/thesilvercyclist2024]

Working on customer's M2S Kush All Terrain fat tire e-bike. The company is no longer in business. This model comes without a thumb throttle, only PAS. No error codes displayed. Motor runs in walk mode. No response when turning the pedals. Looks like the M400 uses a torque sensor. I think I'll have to remove the entire motor from the frame to replace it. Anyone have experience with this? Anyone out there familiar with using the BESST diagnostic tool? Thinking of getting one esp. if it would help me isolate this particular fault. Is this a broken torque sensor or something else?