If the business percentage varies from year to year, you can NOT report the sale in the vehicle section. Say you converted it to personal use or something like that.
You then need to MANUALLY calculate some things and report the sale in the "Sale of Business Property" section, or go to a tax professional.
In your case, when you go through the vehicle section and say you converted it to personal use (and before you actually report the sale in the "Sale of Business Property" section), check if the "Sale of Business Property" shows $0. If it doesn't, it may be getting a number from elsewhere on your return.
