Federal tax Returns

Only the IRS and your State control when and if a Federal or State tax refund is Approved and Issued.

Once a tax return has been Accepted by the IRS or a State, TurboTax receives no further information concerning the tax return or the status of any tax refund. 

If accepted by the IRS use the federal tax refund website to check the refund status - https://www.irs.gov/refunds

After the tax return has been Accepted by the IRS (meaning only that they received the return) it will be in the Processing mode until the tax refund has been Approved and then an Issue Date will be available on the IRS website.
See this IRS website for federal tax refund FAQ's - https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions

Once your return is filed, TurboTax has no control over the processing of your return or the release of your refund.

Due to PATH Act, the IRS holds refunds for EITC/ACTC customers until March 3.  

Here are a couple FAQs to track your refund:
When will I get my federal tax refund?
How do I track my state refund?
Why does Where's My Refund say "approved" but TurboTax still says "accepted"?

Why do some refunds take longer than others?

What if my IRS refund is taking longer than 21 days?