If your boss used a company vehicle to purchase a privately owned vehicle, then the new vehicle does not go on the books.
If your company is taxed as a sole proprietor or a partnership create an income account called gain/loss on asset sales, then journal entries
debit fixed asset, credit gain loss 54663
debit gain loss, credit accum depreciation vehicle, 54663
debit owner equity drawing, credit gain loss, 16000
If the company is a partnership insure the gain loss account has his name and that the tax form shows that additional 16K as income to him.
If the company is a c- or s-corporation, then replace the equity account in the above journal entry with a liability account and the owner will have to repay that 16K.