California Code, Vehicle Code - VEH § 4755

The department shall refuse registration, or renewal or transfer of registration for any commercial motor vehicle subject to Section 4000.6, if the owner or operator of the motor vehicle at the time of the application has been cited for a violation, pertaining to that vehicle, of Division 26 (commencing with Section 39000) of the Health and Safety Code or regulations of the State Air Resources Board adopted pursuant to that division, until the violation has been cleared, as determined by the State Air Resources Board.