Answer: 

It is illegal for OEM companies to void warranties based on non OEM supplies that have been used, as that would infringe on consumer rights.

 

• The Magunson-Moss Warrant Improvement Act
  United States Code Annotated Title 15 Commerce and Trade Chapter 50 Consumer Product Warranties 15 Sec 2302 (c) Prohibition on conditions for written or implied warranty; waiver by Commission No warrantor of a consumer product may condition his written or implied warranty of such product on the consumer’s using, in connection with such product, any article or service (other than article or service provided without charge under the terms of the warranty) which is identified by brand, trade, or corporate name; except that the prohibition of this subsection may be waived by the Commission if— (1) the warrantor satisfies the Commission that the warranted product will function properly only if the article or service so identified is used in connection with the warranted product, and (2) the Commission finds that such a waiver is in the public interest.

• The Sherman-Clayton Antitrust Act
  Section 2. Monopolizing trade a felony; penalty Every person who shall monopolize, or attempt to monopolize, or combine or conspire with any other person or persons, to monopolize any part of the trade or commerce among the several States, or with foreign nations, shall be deemed guilty of a felony, and, on conviction thereof, shall be punished by fine not exceeding $10,000,000 if a corporation, or, if any other person, $350,000, or by imprisonment not exceeding three years, or by both said punishments, in the discretion of the court.