The Magnuson Moss Warranty Act (MMWA) prevents manufacturers from using disclaimers on warranties in an unfair or misleading manner.
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Passed by Congress in 1975 - Section 102(c), 15 U.S.C. 2302(c), the
Magnuson-Moss Warranty Act (MMWA) prevents manufacturers from using disclaimers on warranties in an unfair or misleading manner. The MMWA prohibits tying arrangements that condition coverage under a written warranty on the consumer's use of an article or service identified by brand, trade, or corporate name unless that article or service is provided without charge to the consumer.
The Magnuson-Moss Warranty Act prohibits product manufacturers from conditioning consumer warranties on the use of any original equipment part or service. Furthermore, a manufacturer can only deny warranty coverage if it can demonstrate that a non-original equipment part or related service caused a defect to occur in the original product. In the case of motor vehicles, new car manufacturers have ignored these conditions outlined in Magnuson-Moss and have misled consumers to believe that they must have dealer service shops install only original equipment replacement parts or fear having their new car warranty voided.
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If the aftermarket part fails that's not covered.
The aftermarket part has to create a specific failure related to the claim otherwise they cannot void your warranty
for an unrelated failure.