A warranty is a service under which a product manufacturer promises to replace the product in full or in part if found defective within a declared period of time from the date of its sale. Under US law, all consumer firms have to offer warranty to the products sold by them. Warranty will also be offered to cars. It is called auto warranty.

Under an auto warranty, repair of the vehicle, its maintenance, replacement of inexpensive spare parts and repair of the engine, drive train and power train are carried out for no extra fee. However, the cost of the replacement of expensive spare parts is not covered by the warranty. Similarly, spare parts damaged or rendered ineffective on account of neglegance cannot be replaced under warranty.

The warranty is available on the basis of two factors. The time bound auto warranty is issued for a period of up to two years from the date of the sale of the car. The auto warranty based on distance is offered up to 30,000 miles covered by the car. There is another warranty, which is an combination of both a period of time and mileag based warranties. The auto warranty will be in existence till whichever of the two factors come to an end.