The state board shall, by regulation, require manufacturers of motor vehicles and motor vehicle engines to determine the extent to which emissions-related defects exist in each engine family and to recommend the diagnostic and repair procedures that can result in the identification and correction of these defects under vehicle inspection and maintenance programs.
Source:
Section 43210.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=HSC§ionNum=43210.5..