If you own the vehicle individually, generally the corporation would have an Accountable Plan with you so you get reimbursed for the business portion.
If the corporation owns the vehicle, the corporation deducts all of the costs, but then the personal portion is added to the wages of the employee using it.
Corporate taxes really are NOT a Do-It-Yourself kind of thing. You really should be with a good tax professional that does a lot of work with corporations.