* If the car was repossessed because you failed to make the payments on a loan, the lender may have a lien on the car. This means that they have the legal right to sell the car to satisfy the debt. If this is the case, you will need to pay off the lien in order to sell the car.
* If the car was repossessed because it was involved in criminal activity, the police may have seized the car. In this case, you will not be able to sell the car until the police have released it.
If you are not sure whether or not you can sell your car, you should contact the lender or the police.