Hagens Berman alleges Fiat Chrysler sold about 630,000 2019–2023 RAM 2500/3500 trucks with Cummins diesel engines that emit unlawfully high NOx in real-world driving. The complaint contends FCA and Cummins fitted unauthorized emission-control hardware that impaired compliance and were not disclosed, leaving vehicles noncompliant with EPA and CARB rules, reducing resale value and causing alleged overpayment and health risks. On Dec. 21, 2023, the DOJ announced a $1.675 billion settlement with Cummins—the largest Clean Air Act civil penalty—saying the devices produced thousands of tons of excess NOx. The suit also alleges prior recalls did not remove those controls and that fixes could harm other vehicle performance.