California Code, Vehicle Code - VEH § 27158

After notice by a traffic officer that a vehicle does not comply with any regulation adopted pursuant to Section 27157, no person shall operate, and no owner shall permit the operation of, such vehicle for more than 30 days thereafter unless a certificate of compliance has been issued for such vehicle in accordance with the provisions of Section 9889.18 of the Business and Professions Code or unless the department has checked the vehicle and determined that the vehicle has been made to comply with such regulation adopted pursuant to Section 27157. A certificate of compliance issued for such vehicle shall, for a period of one year from date of issue, constitute proof of compliance with any regulations adopted pursuant to Section 27157 provided that no required pollution control device has been disconnected, modified, or altered or has been adjusted by other than a licensed installer in a licensed motor vehicle pollution control device installation and inspection station subsequent to the issuance of the certificate of compliance. The provisions of this section shall apply to the United States and its agencies to the extent authorized by federal law.