In Engine Manufacturers Association v. State Air Resources Board, 2014 Cal. App. LEXIS 1075, the California Third District Court of Appeal reversed the trial court’s judgment on the pleadings and upheld the California Air Resources Board’s (CARB) authority to adopt regulations requiring the testing and recall of in-use heavy-duty engines to protect air quality.

California Health and Safety Code section 39003 tasks CARB with “coordinating efforts to attain and maintain ambient air quality standards . . . and to systematically attack the serious problem caused by motor vehicles[.]” As part of its effort to improve air quality, CARB requires most vehicle engines certified for sale in California to include an onboard diagnostic system (OBD) that monitors and detects emissions malfunctions. CARB mandates rigorous testing that ensures new engines include a functioning OBD system, as well as compliance by a sample of in-use heavy-duty vehicle engines model year 2010 and later. If the tests show the OBD system does not function properly in the in-use engines, CARB may order the recall and repair of the engine class.

The Engine Manufacturers Association challenged the part of the regulations related to in-use engines. The Association sought a judicial declaration that the regulations exceeded CARB’s statutory authority.  On appeal, the court rejected the Association’s argument and held that, because CARB raised a defense in its answer, the trial court erred in granting summary judgment on the pleadings.

The court explained Health and Safety Code section 39003, in conjunction with other statutes, provides broad authority for CARB to regulate air quality in California. More specifically, Health and Safety Code section 43013 grants CARB the authority to “adopt and implement motor vehicle emission standards, in-use performance standards, and motor vehicle fuel specifications[.]” The court found the challenged regulations furthered CARB’s purpose by facilitating prompt repair of emission-related engine malfunctions and providing an incentive to manufacturers to make improvements in emission system durability.

The court further held the absence of specific statutory provisions regarding compliance testing of in-use heavy-duty engines did not mean the challenged regulations were invalid. Instead, it indicated only that the Legislature did not itself desire to determine the proper method of regulating such testing. The court went on to explain that under section 43013, CARB’s regulations must be “necessary, cost effective, and technologically feasible.” Accordingly, if the regulations were “unduly onerous and costly,” as the Association alleged, the regulations could exceed CARB’s authority. But because this question could not be answered on the pleadings, the trial court erred by granting judgment on the pleadings.

The court next held the trial court erred in finding the regulations were not “reasonably necessary” for CARB to carry out its intended purposes. The Association had the burden of establishing the regulations were not reasonably necessary, but did not even address the issue in its pleadings. Accordingly, the Association failed to meet its burden and judgment on the pleadings was improper.


The court emphasized CARB’s broad authority to develop and enforce regulations to improve air quality in the state. Although no statute specifically allows CARB to order the recall and repair of engines for compliance with air quality monitoring systems, the Legislature’s broad directive to “attain and maintain ambient air quality standards” and “systematically attack the serious problem caused by motor vehicles” empowers CARB to enact such measures.