The lender will sell your vehicle at auction to recover the amount of money that you still owe on the loan. If the sale price of the vehicle is less than the amount of money that you owe, you will be responsible for paying the difference.
If you are unable to pay the difference, the lender may take legal action against you to collect the debt. This could include garnishing your wages or seizing your property.
If you are considering voluntarily repossessing your vehicle, it is important to talk to a lawyer to understand your rights and options.