The Depreciation can't be more than the Cost of the Vehicle.
If you claimed Standard Mileage expense for your vehicle, depreciation was built into the deduction.
If so, when you report that you 'stopped using it for business' leave the Prior Depreciation and AMT Depreciation entries blank and enter a 'Depreciation Equivalent' amount instead (screenshots).
More info:
https://ttlc.intuit.com/replies/5230628