quote:

Magnuson-Moss Warranty Act
States, in part, in Title 15, United States Code, Section 2302, subdivision (c), as follows:

“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 [Federal Trade] 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 Commission shall identify in the Federal Register, and permit public comment on, all applications for waiver of the prohibition of this subsection, and shall publish in the Federal Register its disposition of any such application, including the reasons therefor.”

Under this federal statute, a manufacturer, who issues a warranty on your motor vehicle, is prohibited from requiring you to use a particular brand of air filter, oil filter, or other service or maintenance item, unless such item is provided, free of charge, under your warranty or unless the Federal Trade Commission (FTC) waives this prohibition against the manufacturer.

http://en.wikipedia.org/wiki/Magnuson-Moss_Warranty_Act