macbook pro start up and update and automatic turn off
MacBook Pro
Try SMC and NVRAM resets:
https://support.apple.com/en-us/HT201295
https://support.apple.com/en-us/HT204063
If there is no change, I would reinstall the OSX.
If still no change, a trip to an Apple store is that best option.
Ciao.
macbook pro start up and update and automatic turn off