Is it permissible to sell a car that has some problems at a reduced price equivalent to the cost of its maintenance, without disclosing its defects?

It is not permissible to conceal defects in a car that the buyer would dislike, even if the price is reduced, because that constitutes deception and fraud. Everything that the buyer would dislike or that would diminish his desire for the commodity must be disclosed. The Messenger of Allah, peace and blessings be upon him, said: "Whoever deceives is not of me," and "If they are truthful and make clear, they will be blessed in their transaction, and if they conceal and lie, the blessing of their transaction will be erased."