Alternative Parts & Vehicle Warranties
The Magnuson-Moss Warranty Act makes it illegal for manufacturers and dealers to void your warranty or deny you coverage under that warranty simply because someone other than the dealer did the work or becuase the parts were not made by the vehicle manufacturer.
Using alternatives such as aftermarket parts, recycled parts or remanufactured parts will not void your warranty. Doing repairs yourself, using an independent repairer or retail chain shop will not void your warranty either.
For more information:
FTC Consumer Alert: Auto Warranties, Routine Maintenance, and Repairs: Is Using the Dealer a Must?
Magnuson-Moss Warranty Act Excerpt