Why is my phone's turbo charge doesn't function anymore?

Make sure your charger and cable are still good and provide turbo charge. Also if your battery drains fast you should replace it and a bad battery also could take less power at charging, so that's why it doesn't turbo charge. Also try to clean your charging cable and port with a toothbrush with some alcohol on it. Be careful put a small amount of alcohol on your toothbrush and not directly to the port and before plug your charger on, make sure it is dried.