A catch can is like a new air filter. They can't deny a warranty claim for it. It's the law:
Can an automotive dealership void your warranty?
Understanding the Magnuson-Moss Warranty Act of 1975.
Nearly everyone has heard about someone who has taken a vehicle that has been modified with aftermarket parts to a dealer for warranty service, only to have the dealer refuse to cover the defective items. The dealer usually states that because of the aftermarket parts the warranty is void, without even attempting to determine whether the aftermarket part caused the problem.
This is illegal.
Vehicle manufacturers are not allowed to void the vehicle warranty just because aftermarket parts are on the vehicle. To better understand this problem it is best to know the differences between the two types of new car warranties and the two types of emission warranties.
When a vehicle is purchased new and the owner is protected against the faults that may occur by an expressed warranty - an offer by the manufacturer to assume the responsibility for problems with predetermined parts during a stated period of time. Beyond the expressed warranty, the vehicle manufacturer is often held responsible for further implied warranties. These state that a manufactured product should meet certain standards. However, in both cases, the mere presence of aftermarket parts doesn't void the warranty.
There are also two emission warranties (defect and performance) required under the clean air act. The defect warranty requires the manufacturer to produce a vehicle which, at the time of sale, is free of defects that would cause it to not meet the required emission levels for it's useful life as defined in the law. The performance warranty implies a vehicle must maintain certain levels of emission performance over it's useful life. If the vehicle fails to meet the performance warranty requirements, the manufacturer must make repairs at no cost to the owner, even if an aftermarket part is directly responsible for a warranty claim, the vehicle manufacturer cannot void the performance warranty. This protection is the result of a parts self - certification program developed by the Environmental Protection Agency (EPA) and the Specialty Equipment Market Association (SEMA).
In cases where such a failed aftermarket part is responsible for a warranty claim, the vehicle manufacturer must arrange a settlement with the consumer, but by law the new - vehicle warranty is not voided.
Overall, the laws governing warranties are very clear. The only time a new vehicle warranty can be voided is if an aftermarket part has been installed and it can be proven that it is responsible for an emission warranty claim. However, a vehicle manufacturer or dealership cannot void a warranty simply because an an aftermarket equipment has been installed on a vehicle.
If a dealership denies a warranty claim and you think the claim falls under the rules explained above concerning the clean air act (such as an emission part failure), obtain a written explanation of the dealers refusal. Then follow the steps outlined in the owners manual. However, if this fails, then phone your complaint in to the EPA at (202) 233-9040 or (202) 326-9100.
If a dealer denies a warranty claim involving an implied or expressed new car warranty and you would like help, you can contact the Federal Trade Commission (FTC). The FTC works for the consumer to prevent fraudulent, deceptive and unfair business practices in the marketplace and to provide information to help consumers spot, stop and avoid them. To file a complaint, you can call toll-free, 1-877-FTC-HELP (1-877-382-4357), or use the online complaint form. The FTC enters Internet, telemarketing, and other fraud-related complaints into Consumer Sentinel, a secure, online database available to hundreds of civil and criminal law enforcement agencies worldwide.