The California Air Resources Board (CARB) has announced that 500,000 Cummins heavy-duty and medium-truck engines will be recalled due to excess NOx emissions caused by defective catalysts. The agency said Cummins is working cooperatively on the recall effort.

The California Air Resources Board (CARB) has announced that 500,000 heavy-duty and medium-truck engines manufactured by Cummins will be recalled due to excess emissions caused by defective catalysts. Cummins worked collaboratively with CARB on the voluntary recall which constitutes the largest such effort for heavy-duty trucks to date.

The excess emissions were discovered after CARB launched its new Heavy Duty In-Use Compliance program in 2016. The Cummins action marks the first major recall resulting from the program, in which subject vehicles are equipped with Portable Emissions Measurement Systems (PEMS) to measure truck emissions while operating on streets and highways under typical operating demands and conditions.

After initiating the program, CARB said initial readings of some of the Cummins engines revealed higher than expected emissions of nitrogen oxides (NOx). This led to more comprehensive testing which confirmed that the selective catalytic reduction (SCR) systems were defective, causing emissions of NOx to exceed state and federal standards.

CARB said the same issue was found to affect about 60 Cummins engine families used in a wide range of vehicles, from large commercial trucks to larger pickup trucks and some buses.

“Increased vigilance and testing led directly to a positive result,” said said CARB Chair Mary D. Nichols. “Our new heavy-duty in-use compliance program ensures that heavy-duty and other trucks already in operation meet the required emissions standards both in the lab and on the road. Our portable testing equipment tells us exactly how clean a truck is when it’s actually operating in the real world: pulling a full load and driving on roads and through neighborhoods where people live.”

After CARB shared the initial findings with Cummins, the company conducted its own testing to confirm the failures and agreed to institute a voluntary recall to replace the catalysts, ultimately affecting more than 800,000 vehicles. This total includes about 232,000 Dodge Ram 2500 and 3500 vehicles with Cummins engines that had the same SCR issues. Recalls for those vehicles were approved in July 2016 and July 2017, respectively and are already underway.

In its second quarter earnings announcement, Cummins said it had finalized its plans and recorded a pre-tax charge of $181 million for the expected costs of the recall, which it said addresses the performance of an aftertreatment component in certain on-highway products produced between 2010 and 2015 in North America.

CARB said the trucks will be recalled in a two-phase operation. Starting in August, owners of the 500,000-plus affected vehicles will receive letters with instructions on how to get their catalysts replaced or receive reimbursement for the cost of the replacement. The second phase begins in March 2019.  Replacing the catalyst is required for vehicle owners to renew their California DMV registration on most engine families.

CARB said it was noteworthy that the cause of the excess emissions was purely mechanical – the faster-than-expected degradation of the catalyst – and not the product of a ‘defeat device’ or cheating on tests. The degrading catalysts also do not pose a safety issue, and do not affect current model year Cummins engine families, CARB said.

Once Cummins was made aware of the issue, they cooperated with CARB and U.S. EPA and agreed to recall the full range of engine families, pay for all required repairs and reimburse owners who may have already paid for an SCR replacement.

“Today’s recall is a great example of how government and industry work together to protect health and the environment.” said EPA Office of Air and Radiation Assistant Administrator Bill Wehrum. “This is the way it’s supposed to work. Our follow-up testing seeks to make sure that pollution controls work throughout an engine’s useful life. And, if they don’t, then companies step up to set things right.”