There are 2 options to "expense" a vehicle, here are the basics...
1 - the mileage method, miles used for business purposes multiplied by the current amount allowed.
this does not include gas, depreciation, repairs, maintenance, insurance, interest, etc and you cannot take any of these expenses if you take the mileage method
2 - Actual method, business miles divided by the total miles driven for the year gives you a percentage. This same percentage is applied to all expenses incurred.... depreciation, insurance, repairs, interest, gas, maintenance, etc. This would genenerate the amount of your deduction.
As someone stated, if the vehicle is owned by the corporation, and it is used for personal use, there is a calculation to add income to your W-2 for that use. The corporation takes 100% of all expenses.
As always... consult with your CPA or tax advisor. The rules are complicated and everyone's situation is different. What applies to one, may not work for another.
Michele