There is defect in car or material, seller is unaware about it: Compensation or Cancel the deal

 Islamic ruling:

Concealing the defect and fault of car or other materials by seller...

It says in Kashshaf al-Qina‘ (3/218): If someone buys a defective product and was not aware of it at the time of the purchase, then he has the choice, regardless of whether the seller was aware of the defective and concealed it from the purchaser, or he was not aware of the defective. …

The purchaser has the choice between returning it, so as to make up for what he has lost and to alleviate any harm that may affect him if he keeps it, as a result of the reduction in the value of the item…

Or, if he returns it, he should receive the price in full, because by cancelling the deal, the purchaser is entitled to take back the price in full. …

Complete Answer:https://islamqa.info/en/answers/258447/he-bought-a-car-after-checking-it-then-he-found-a-defective-of-which-the-seller-was-not-aware-does-he-have-the-option-to-cancel-the-deal