An Internet search reveals a transcript 971 code can mean the IRS has sent or is about to send a notice regarding your tax account. In a search the adjacent "CP 0075" could mean a CP75 letter asking for documentation of something in your return, possibly related to a tax credit, such as EIC, ACTC, etc. If you receive an IRS notice/letter, it should have instructions on how to proceed, as well as a phone number if you need to phone the IRS for more info.
If you have an IRS online account, you can log in and go to the notices & letters section to see if it shows any notice/letter that was sent or about to be sent.
