A putative class action lawsuit was filed last month against Mazda Motor of America Inc. in a New Jersey federal court. The lawsuit accuses Mazda of concealing from consumers an engine valve system defect in certain Mazda vehicles. The automaker is accused of refusing to make the required repairs. The suit alleges Mazda falsely advertises and guarantees that its new vehicles are defect-free. It alleges that Mazda knows that some of its vehicles’ engines have faulty continuous variable valve-timing assembly, causing its engine’s timing chain to loosen or detach, which can lead to partial or total engine failure. Although the defect is covered under Mazda’s warranty, it’s alleged that the automaker refuses to repair the defect.