I am glad I kept my old Bulls e-mtb since my Amflow has been down for almost a month, is still in the shop, and nobody knows when a replacement part will be avaliable.
That's why I tested it with the front brake only. Even just the front brake causes the speedometer to go to zero. And it stays at zero even after I let off the brakes. That would indicate it is nothing to do with the sensor ring. But I will check.
I have another observation on my failed speed sensor issue. I notice whenever I put on the brakes (front, rear, or both) the speed on the display goes immediately to zero (0) while still moving. As soon as I start to pedal it comes back up to a realistic speed number. Very repeatable.
Any ideas?
That is the same conclusion that I have figured out from this and other forums. I tried all those things you mentioned to no avail. The sensor sits about 1.5mm from the ring. Everything is solid and has been checked multiple times. My bike is almost new at ~250miles. Still completley stock...
What is the final and best solution for the Amflow speed sensor 0x2701006f error code? Replacing the speed sensor doesn't but replacing the motor does according to many people.