Make sure the motor power level is not set to 0. The power level needs to be set to 1–4 for the Turbo Boost to function. 

The motor has integrated safety measures to prevent it from overheating. If you've been holding down the Turbo Boost button for a long time, or riding uphill or in windy conditions extensively, the bike may temporarily deactivate the Turbo Boost. When the motor has cooled, Turbo Boost will automatically reactivate. 

If you think you're not getting the same performance you used to, please contact us via our support page.