California Code, Health and Safety Code - HSC § 43009.5

(a) If, based on a review of information derived from a statistically valid and representative sample of vehicles, the state board determines that a substantial percentage of any class or category of vehicles certified under the optional standards of Section 43101.5, and of Section 1960.15 of Title 13 of the California Administrative Code, exhibits, prior to 75,000 miles or seven years, whichever occurs first, an identifiable, systematic defect in a component listed in paragraph (2) of subdivision (c) of Section 1960.15, which causes a significant increase in emissions above those exhibited by vehicles free of defects and of the same class or category and having the same period of use and mileage, the state board may invoke its enforcement authority under Section 43105 to require remedial action by the vehicle manufacturer. The remedial action shall be limited to owner notification and repair or replacement of the defective component. As used in this section, the term “defect” shall not include failures which are the result of abuse, neglect, or improper maintenance.

(b) Nothing in this section shall limit or otherwise affect the recall authority of the state board, except as provided in subdivision (a).