Provided the car starter is properly installed and is not defective, installation of a car starter does not void the car's warranty. The Magnuson-Moss Warranty Act protects consumers from having either manufacturers or dealers void warranties for installing aftermarket parts, according to the Federal Trade Commission.
If the car starter is defective or installed incorrectly and causes damage to a part of the car covered by the warranty, the warranty may be void, notes the FTC. Consumers should be aware of all of the terms of their warranties in order to ensure coverage. This includes being aware of the warranty coverage length, following any prescribed maintenance outlined in the warranty and keeping accurate records of any and all service performed on your car.