A warranty is an important part of any consumer purchase. It's part of the agreement between you and the manufacturer of that product. It constrains the manufacturer to make good any deficiencies, pay for any repairs, and ensure that the product is fit for purpose. It obligates the consumer to follow the instructions and maintain the product according to manufacturers recommendations.
In the case of a car, that can mean a bunch of money. Like any contract, it can be broken if one side doesn't abide by their obligations. Fortunately, manufacturers are legally obliged to keep up their end of the deal, but the consumer is free to break theirs. The cost of not abiding by the contract is that it voids the warranty.
The most critical point about a motor vehicle warranty is that any work carried out on the motor-vehicle doesn't have to be done by the main dealer. Thanks to the Magnuson-Moss Warranty Act you can have your auto serviced at any auto repair shop. That is as long as the garage follows the manufacturers recommendations,uses high quality parts, and records the services in the log book.
This is quite a major advantage, as main dealers could be considerably more expensive than independents. It isn't uncommon to see a cost savings of of somewhere up to 20-30 percent when using an independent car repair facility. As well as the standard warranty, there is also the extended warranty for newer vehicles. This is a purchase that extends elements of the existing warranty for a set number of years.
Not all extended warranties are created equal, so it's critical to get the right one for your Vehicle, and your situation. The Magnuson-Moss Act also applies to extended warranties, so you can use an independent shop to maintain that as well. The largest deal breaker of any warranty is lack of maintenance. A motor vehicle is a living thing. It needs gas for energy, air to breathe and oil as blood. All these things need to be clean and of the right type for the motor-vehicle. A lack of maintenance on any motor vehicle will invalidate the warranty. That means it must be serviced when the manufacturer suggests, it needs the right kind of oil and the right parts.
Misuse is such a broad term, but it's one that's used quite a lot in warranty claims. A vehicle will have a given purpose, passenger capacity, load weight and capability. Any activity which goes outside these and causes damage will not be covered under the warranty. The obvious activities are racing, off-roading, or overloading when the vehicle isn't designed for it.
All of the manufacturers recommendations and specifications will be listed in the handbook. It's your job as the owner to read and digest them if you want to keep your warranty. The warranty documentation will go into details about what's required, so it's a really good idea to read that too.
Vehicle modification is another common way to void a warranty. If you like adding bits, taking them away or generally fiddling with your car, then you probably aren't that interested in warranties anyway. Manufacturers take a dim view of warranty claims on modified cars. That's true even if the warranty claim is for an auto part that hasn't been modified.
To maintain a warranty, have the auto serviced at required intervals and keep all the invoices. Follow the warranty specifications as much as possible and only use the vehicle for the purpose it was designed for.
If you need work done under warranty, take it to an independent motor vehicle repair shop and let them give you an assessment, and get help so it is properly taken care of by the manufacturer. For the vast majority of cases, the garage will be more than willing to aid you in making sure this work is completed with no hassles.