Cummins is cooperating with CARB, and says it has already come up with a way to bring the vehicles into emissions compliance. However, the company will still have to recall around 500,000 trucks manufactured from 2010 and 2015 in order to make that happen.
The problem has been linked to defective catalysts, which are used to neutralize harmful emissions like nitrogen oxide (NOX). CARB found that the Cummins catalysts degraded more quickly than expected, leaving vehicles still running but without a working emissions control system.
Interestingly, the problem with Cummins catalysts may have never been found had it not been for the VW emissions fiasco in 2016. As a result of the scandal, CARB began testing older vehicles under real-world driving conditions rather than simply testing newer vehicles. Using a Portable Emissions Monitoring System, the agency identified the problem with the Cummins line of engines.
“The testing confirmed that the selective catalytic reduction (SCR) systems were defective, causing emissions of NOX to exceed state and federal standards,” CARB said in a press release. “The same problem was found to affect about 60 ‘engine families’ under the Cummins name found in a wide range of vehicles, from big-rigs, to larger pickup trucks and some buses.”
Cummins is also currently in the process of conducting a separate recall of about 232,000 Ram 2500 and 3500 pickup trucks made by Fiat Chrysler Automobiles (FCA). The U.S. Environmental Protection Agency (EPA) opened an investigation into the trucks in 2017.
Source: Ars Technica