You will need to come up with a reasonable estimate if you wish to claim any miles related to business use of your vehicle. Hopefully it is a number that you can back up using documentation such as service records where the odometer readings are reported. Otherwise, in the unlikely event that your return is examined by the IRS, you could be asked to provide that documentation.
If you are still driving the vehicle for business purposes, then start keeping records now for 2025. It is a requirement in order to be able to claim the vehicle expense on your tax return.
See the following TurboTax help article to learn more: