You can deduct state income tax, or state sales tax, but not both. In most cases, the income tax will be larger. For the sales tax deduction, you can either claim the exact amount you paid (if you kept records) or you can deduct a standard amount based on your income. You are allowed to add tax paid on a vehicle to the standard amount. TurboTax may not ask you about the sales tax deduction if it calculates that the income tax deduction is larger, but if not, you can manually go to that section of the interview on the Deductions and Credits page. Even if you manually enter the car sales tax though, TurboTax will automatically deduct your state income tax if it is the larger deduction.
