Are you self-employed? Or did you use the car while working for an employer?
If you are self-employed, please go to:
Income> Self-Employment>Expenses>Vehicle -- select the the "review" button to edit the information or select "delete" (the trashcan icon) to completely remove that vehicle information
If you use the vehicle for job, please go to:
Deductions & Credits>Employment Expenses>Job Expenses for W-2 income and select "Revisit"
You should see a job-related expenses summary, "Edit" the occupation that has your car expenses entered.
Go through the interview until you see the screen: "Vehicle Summary" (right after the home office topic).
On that screen you should see the original car expenses you claimed and can either "edit" or "delete" the entry.