Sold a car without disclosing the fault: what do I do?

In the Name of Allah, Most Merciful and Compassionate

May His blessings and peace be on His Beloved Prophet, the best of creation, and his family, companions, and followers

Walaikum assalam wa rahmatullah,

1. It is obligatory for you to compensate the individual in question to the extent of the fault in question (unless they willingly forgive it), if you are able to find the person, taking reasonable means. It is not obligatory to give the entire price in charity.

2. If you are unable to find the person, after having taken reasonable means, then it would be obligatory to give this amount in charity, with the intention of clearing your wealth of haram earnings and of the reward of the charity reaching this person in question.

3. In the Hanafi school this money is given in charity to a needy individual, for the reasons explained in the links below. [cf: Ali Haydar, Durar al-Hukkam Sharh Majallat al-Ahkam, 4.592, quoting al-Fatawa al-Hindiyya; Ibn Abidin, Radd al-Muhtar]

How do I determine the material value of the defect?

In order to determine the defect, you would have to determine how much the market price of the car would have been reduced by the presence of the defect, according to reliable individuals aware of market prices. This is affirmed in the Majalla:

336. A defect consists of any faults which, in the opinion of persons competent to judge, cause a depreciation in the price of the property.

Repentance also obligatory

With this, it is obligatory to repent from the cheating itself:

“It is not permitted to conceal defects in items sold or in the price paid, because cheating is forbidden,” explains Imam `Ala’ al-Din al-Haskafi in his al-Durr al-Mukhtar. [‘Bab Khiyar al-`Ayb’]

Wassalam,

Faraz Rabbani