In a statement made yesterday, the Federal Trade Commision stated that it had sent warnings to six major manufacturers of cars, mobile phones, or video game consoles. The warning stated that policies requiring users to repair their products via a preset list of vendors or replacement parts in order to maintain a product's warranty is, in fact, illegal.
https://www.notebookcheck.net/FTC-slams-companies-that-require-repairs-using-certain-parts-or-vendors-to-maintain-a-warranty.296914.0.html