New CARB rules to increase cost of heavy-duty engines

CALIFORNIA — Last week, the California Air Resources Board (CARB) adopted a proposal that will result in the heavy-duty (HD) engines used in motorhomes needing to have more sophisticated on-board diagnostics (OBD) systems in the future. The results of these new requirements are twofold, reported RVIA.

First, it will result in increased engine costs. CARB projects an additional cost of $43/engine due to the amendments. Costs, however, will likely increase depending on how engine manufacturers certify their OBD systems. It is estimated that the amendments will approximately triple the cost of certifying OBD systems with deficiencies. In the future, an engine with the maximum possible number of OBD system deficiencies could incur added costs of $1,250 per engine.

This increase in penalties is intended to force manufacturers to design their OBD systems to comply with all requirements (currently not the case). Today, because the penalties for deficiencies are low, it is common for manufacturers to certify noncompliant systems and pay the penalties for deficiencies (which today amounts to no more than $450/engine). The burden of compliance with these new rules will be on engine manufacturers, not motorhome manufacturers.

Second, HD engines in the future will collect and store NOx and GHG data. This data will be analyzed to ensure that engines are performing as intended in the real world. Collecting this data onboard will allow CARB to assess how vehicles are complying with emissions standards in-use. As we know, it is not uncommon for vehicles to perform differently on the road than in the lab. This rule change is designed to prevent that variation.

For the full memo from the hearing, click here.
Please contact Mike Ochs at for additional information.

SOURCE: RVIA News & Insights

Ronnie Wendt

Ronnie Wendt

Ronnie Wendt has been a writer/editor for more than 25 years, working in law enforcement, aviation, supply chain and the RV industry. She's not a stranger to RVs, however. She grew up camping, and still camps as many weekends as she can every year. She is the owner of In Good Company Communications and can be reached at

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