By Amy E. Feldman

PHILADELPHIA (CBS) – The Warranty Act isn’t the law that says that if you have a car warranty, the only thing that breaks will be what isn’t covered. That’s Murphy’s law. But the Warranty Act is important nonetheless.

Unbeknownst to many consumers, the Magnuson-Moss Warranty Act is a law, enforced by the Federal Trade Commission, that says that it’s illegal for a dealer to say your warranty coverage is void because you had routine maintenance like oil changes, new brake pads, inspections, or repairs performed by someone other than the dealer, just as it is illegal for the dealer to say your warranty is void because you used after market or recycled parts.

That said, if the parts or the work done by others is what caused the problem then the warranty may in fact be void. But if your dealer denies coverage on the warranty just because you had the work done elsewhere, it is illegal.

BMW just settled an FTC complaint alleging it illegally told consumers their warranty was void because of work done elsewhere. If you think your dealer is illegally limiting your warranty, call the FTC.

If the car doesn’t break down until the warranty is over, chalk it up to Murphy’s Law.