N.J. Stat. Ann. § 56:12-40

12. It shall be an affirmative defense to a claim under this act that the alleged nonconformity does not substantially impair the use, value, or safety of the new motor vehicle or that the nonconformity is the result of abuse, neglect, or unauthorized modifications or alterations of the motor vehicle by anyone other than the manufacturer, or, in the case of an authorized emergency vehicle, the manufacturer, co-manufacturer, or post-manufacturing modifier, or its dealer or distributor.