1040 Line 12b CARES act is giving credit for volunteer mileage (believe should be Cash only)

You are correct - the deduction is limited to cash donations only. This issue has been identified by the TurboTax team, which is working on a solution.

In the meantime, you may be able to fix this on your return...

1. Go back to Deductions & Credits >> Donations to Charity.
2. Delete the charity you entered for the volunteer work.
3. Continue back to the Deductions & Credits screen.
4. Scroll to the bottom and click on Wrap up tax breaks.
5. Without making any other entries, continue to the page that shows you are getting the Standard Deduction.
6. Continue to the next page that asks your total charitable cash contributions for the year.
7. Delete any number that appears in the box (this is the spot where TurboTax causes an error).
8. Continue to the next page.

Now, go to Tax Tools in the left column. Choose Tools, then View Tax Summary.

In the left column, choose Preview my 1040. Scroll down to Line 12 b, which should now be empty.

If this process was successful, use the Back link above Federal Tax Summary in the left column to go back to your return.

1. Navigate back to Deductions & Credits >> Donations to Charity and re-enter the info for the volunteer work.
2. Scroll to the bottom and click on Wrap up tax breaks.
3. Without making any other entries, continue to the page that shows you are getting the Standard Deduction.
4. To confirm your deduction has been processed correctly, go to Tax Tools in the left column.
5. Choose Tools, then View Tax Summary.
6. In the left column, choose Preview my 1040. Scroll down to Line 12 b, which should now show only your cash contributions (if any).