This IRS Tax Topic says to report income and expenses related to personal property rentals on Schedule C (Form 1040), if you are in the business of renting personal property.
In TurboTax Online Premium, you would report the income and expense under Federal and Wages & Income, then Self-Employment and Self-employment income and expenses.
Under Expenses, report the initial cost and improvements under Vehicle.
Generally, a rental activity is a passive activity even if you materially participated in the activity.