My Philips Sonicare toothbrush turns off by itself
Check the brushing mode selected
Here is an overview of possible modes and their timings:
Clean = 2 minutes
White = 2:30 minutes
Polish = 1 minutes
Gum care = 3 minutes
Sensitive = 2 minutes
Gum health = 3:20 minutes
Tongue care = 20 seconds
Changes in vibration while brushing
These features indicate when you are supposed to move onto the next section of your teeth via a brief change in vibration. These changes are normal. The toothbrush will automatically turn off at the end of the brushing session.