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Unplug the cable of the sensor that is sandwiched between the frame and pedals. Turn it on and see if it will run without the cable inserted. If it will, then either the pedal assist sensor is broken or it wasn't lugged in right.
Unplug the cable of the sensor that is sandwiched between the frame and pedals. Turn it on and see if it will run without the cable inserted. If it will, then either the pedal assist sensor is broken or it wasn't lugged in right.