What to do if the Xiaomi Smart Electric Toothbrush T501 vibrates weakly and can’t clean teeth completely?

The pressure of brushing teeth should not be too strong. There is an Over-pressure protection function on the Xiaomi Smart Electric Toothbrush T501, with the indicator on the top keeping in red.
The Gentle Mode, with weak vibration, is suitable for novices. The Standard Mode is optional. In addition, you can customize the Custom Mode for the cleaning intensity in the Mi Home/Xiaomi Home APP.