I don't know what a T2125 or Chart A is, because they don't exist anywhere I can find in the federal program for a U.S. Tax return. Is this for some state? Or a Canadian return?
Basically, you take the "per-mile" deduction, or the actual expenses. You can't take both.
All vehicle data is entered in the Business Vehicle Expenses section, and nowhere else.
If this is for a Canadian tax return, then disregard all the above. Overall, my guess is your question is for a Canadian tax return. If so, seek assistance in the Canadian support forum for TurboTax at https://support.turbotax.intuit.ca/contact/
Note that per the data provided on that page, they are closed Aug 6th. But that doesn't mean other users in that public forum can't offer you some assistance.