Once your return has been filed & accepted, you cannot enter banking information into TurboTax.  The IRS is going to give taxpayers the chance to enter their own banking information. 

The IRS does not have my direct deposit information. What can I do?

In the coming weeks, Treasury plans to develop a web-based portal for individuals to provide their banking information to the IRS online, so that individuals can receive payments immediately as opposed to checks in the mail.

https://www.irs.gov/newsroom/economic-impact-payments-what-you-need-to-know