Frequently Asked Questions - Cummins Violation of Clean Air Act Vehicle Emission System Controls Requirements

2024 Cummins Settlement Resources

On this page:

  1. What is this settlement about?
  2. What are the key elements of the agreement?
  3. I’ve seen different penalty numbers. Which is it?
  4. How many vehicles fall under this settlement?;
  5. Which vehicles are covered by this settlement? Which ones will be recalled?
  6. What does this mean for Ram 2500 and 3500 diesel vehicle owners?
  7. How does EPA know that the emissions modification will work?
  8. Are the same Ram 2500 and 3500 vehicles sold in Canada as well?
  9. What is a defeat device?
  10. What exactly is this software? What does it do? How does it work?;
  11. How did EPA discover the violations? When?
  12. What exactly did Cummins do wrong?
  13. What are the public health consequences of Cummins’s violations?
  14. Is this related to the recent enforcement initiative on Stopping Aftermarket Defeat Devices?
  15. What is California's role in all of this? Will they receive a portion of the money?
  16. What happens to the consent decree now that it is filed with the court? What is the timing?  What happens next in the litigation?
  1. What is this settlement about?

EPA states in the complaint that Cummins was violating the Clean Air Act (CAA) because the software is designed for its Ram 2500 and 3500 diesel vehicles contained undisclosed features and emissions defeat devices. EPA and the Department of Justice announced on January 10, 2024, a settlement agreement that contains the largest civil CAA penalty, which is also the second largest environmental penalty, environmental mitigation, and recalls most or a significant number of the vehicles. More information about the settlement agreement is available on EPA’s case summary of the Cummins settlement web page.

  1. What are the key elements of the agreement? 

The settlement addresses the Clean Air Act violations by requiring Cummins to: (1) pay a substantial civil penalty to ensure the company does not keep its profit from the defeat devices and to deter future violations; (2) bring the vehicles into compliance with the applicable Clean Air Act vehicle emission standards; (3) perform a mitigation project that reduces excess nitrogen oxides (NOx) emissions from locomotives in order to offset the excess emissions caused by the defeat devices; and (4) take measures to prevent future violations.

Highlights of the settlement agreement include:

  • Civil Environmental Penalty: $1.675 billion
  • Federal Mitigation: Repowering 14 road switch locomotive engines and 13-yard switch locomotive engines, as well as installing idle reduction technology on 50-yard switch engines.
  • Vehicle Recall: CAA compliant recall of at least 85% of affected vehicles within three years.
  • Enhanced Testing and Corporate Compliance: Enforceable measures to prevent future violations.
  1. I’ve seen different penalty numbers. Which is it?

Cummins will pay a total of $1.675 billion in penalties to the United States and California to resolve this joint settlement. Of that, $1.642 billion is for the Clean Air Act violations and $33 million is for related claims under California state law. The Clean Air Act penalty will be paid as $1.478 billion to the U.S. Treasury and $164 million to the California Air Resources Board.

  1. How many vehicles fall under this settlement? 

Nearly one million vehicles with this software were sold in the United States from 2013 to 2023. Approximately 630,000 model year 2013 through 2019 Ram 2500 and 3500 diesel vehicles will be eligible for a software recall and extended warranty. Approximately 330,000 additional model year 2013 through 2023 Ram 2500 and 3500 diesel vehicles contain software that was previously undisclosed to the government but does not need to be recalled.

  1. Which vehicles are covered by this settlement? Which ones will be recalled?

Visit EPA’s Cummins Settlement Nationwide Recall Program Overview web page for information on the model year 2013 – 2023 Ram 2500 and 3500 diesel vehicles.

  1. What does this mean for Ram 2500 and 3500 diesel vehicle owners?

If an owner’s vehicle is affected, Ram has or will send the individual a letter notifying them about the recall. The vehicle owner can schedule an appointment to have their vehicle repaired. The recall consists only of a software update, also called a “software reflash”. No hardware changes are necessary. Once Cummins repairs the vehicle, Cummins will provide the vehicle owner with an extended warranty for the emission control system. The extended warranty is also available to owners that have already received the recall and to late-model year 2019 vehicle owners who purchased vehicles that were originally produced with the recall software. For additional information about the recall, please see EPA's Cummins Settlement Nationwide Recall Program Overview web page.

  1. How does EPA know that the emissions modification will work?

Cummins, EPA, and the California Air Resources Board (CARB) have performed extensive emissions testing to demonstrate that the emissions modification works and maintains emission controls that will meet applicable emission standards under real world driving conditions. This testing included standard regulatory emissions tests (“on-cycle” testing), as well as special tests (“off-cycle” testing) conducted on-road using a Portable Emissions Measurement System (also called a PEMS test).

Cummins will demonstrate that vehicles that receive the emissions modification will remain in compliance with Clean Air Act applicable emission standards for the vehicles’ full useful life. The model year 2019 Ram 2500 and 3500 diesel vehicles were fixed in advance of the normal in use testing under EPA regulations. Under the Settlement, the durability of the fix for the model year 2013-2018 Ram 2500 and 3500 diesel vehicles will be verified through enhanced in-use testing of model year 2018 vehicles. Cummins may incur additional penalties and perform additional mitigation if the vehicles fail this in-use compliance testing.

  1. Are the same Ram 2500 and 3500 diesel vehicles sold in Canada as well?

Yes, these same vehicles were also sold in Canada. Any of these vehicles that were originally sold in Canada but have since been imported to the United States and are currently registered here will be eligible to receive the software update.

For any questions regarding the vehicles sold in Canada or the Canadian regulatory program please contact Environment and Climate Change Canada by email at enviroinfo@ec.gc.ca or by telephone toll free at 1-800-668-6767.

  1. What is a defeat device?

Generally, a defeat device is any part or component that defeats any element of design of a vehicle or engine installed to comply with the Clean Air Act. In this case, the alleged defeat devices were various software components.

Specifically in the context of certifying motor vehicles, a defeat device is a vehicle design feature “that reduces the effectiveness of the emission control system under conditions which may reasonably be expected to be encountered in normal vehicle operation and use…” EPA may allow such features to be included in a vehicle, but only if: (1) such conditions are substantially included in the Federal emission test procedure; (2) the need for the feature is justified in terms of protecting the vehicle against damage or accident; (3) the feature does not go beyond the requirements of engine starting; or (4) the software is justified for use in emergency vehicles.” Source: 40 C.F.R. § 86.1803-01.

  1. What exactly is this software? What does it do? How does it work?

Cummins installed software in the electronic control module (ECM) of these vehicles that reduced the effectiveness of the selective catalytic reduction (SCR) system. In some normal driving conditions, the system is impacted, which increases the level of nitrogen oxides (NOx) emissions coming out of the vehicle tailpipe. During California Air Resources Board (CARB) and EPA testing, the vehicles produced compliant emission results. At other times during actual vehicle operation, the SCR failed to adequately address the NOx emissions.

  1. How did EPA discover the violations? When?

EPA discovered inconsistent emissions behavior in these vehicles through testing at the National Vehicle and Fuel Emissions Laboratory (NVFEL). The testing raised questions about whether emissions were being adequately controlled in normal driving conditions. EPA initially identified alleged defeat devices in the model year 2019 diesel Ram 2500 and 3500 diesel vehicles, and that discovery led to further questions.

EPA began performing this specific type of testing after the September 2015 Volkswagen diesel emissions scandal and announced that going forward it would perform additional testing “using driving cycles and conditions that may reasonably be expected to be encountered in normal operation and use, for the purposes of investigating a potential defeat device.”

  1. What exactly did Cummins do that violated the Clean Air Act?

Cummins developed software that helped the vehicles pass emission testing but increased emissions of nitrogen oxides (NOx) in normal driving conditions and used it model years 2013 through 2018. Cummins developed different illegal software that increased emissions of nitrogen oxides for use in model year 2019 Ram 2500 and 3500 diesel vehicles. This kind of software is known as a defeat device because it is designed to cheat emission reduction requirements. In all, Cummins installed alleged defeat device software in 630,000 Ram 2500 and 3500 diesel vehicles, model years 2013-2019.

Additionally, Cummins failed to disclose to EPA and CARB other software in these vehicles and in an additional 330,000 vehicles from model years 2019-2023; although this failure to disclose also violated the Clean Air Act, this software calibration did not include defeat device features and therefore did not create excess emissions.

  1. What are the public health consequences of Cummins’s violations?

Testing has shown that there is an increase in harmful nitrogen oxides (NOx) emissions from these vehicles. The increase results from the reduced use and reduced efficiency of the selective catalytic reduction (SCR) system.

NOx pollution contributes to harmful smog producing ozone and exposure to fine particulate matter that gets lodged in the lungs. Exposure to these pollutants has been linked with a range of serious health effects, including increased asthma attacks and other respiratory illnesses. Exposure to ozone and particulate matter has also been associated with premature death due to respiratory-related or cardiovascular-related effects. Children, the elderly, and people with pre-existing respiratory disease are particularly at risk of health effects from exposure to these pollutants. Recent scientific studies also indicate that the direct health effects of NOx are worse than previously understood, including respiratory problems, damage to lung tissue, and premature death.

  1. Is this related to the recent enforcement initiative on Stopping Aftermarket Defeat Devices?

No, defeat devices used by motor vehicle manufacturers are different than aftermarket defeat devices even though both may involve software calibrations that affect vehicle operations and emission controls. 

Vehicle manufacturers are required to calibrate their emission controls to meet emission standards and certification requirements. When those calibrations behave one way during required testing and another way in real world conditions, they are defeat devices, as prohibited in regulations such as 40 C.F.R. § 86.1803-01. 

Once a vehicle is certified, third parties may not change the software that controls emission performance. Aftermarket hardware and software that removes or bypasses the certified emission controls are known as aftermarket defeat devices, which are prohibited by Clean Air Act section 203(a)(3).

  1. What is California's role in all of this? Will they receive a portion of the money? 

California is an active partner with EPA in testing these vehicles and is a co-plaintiff in EPA’s Settlement.

Section 209 of the Clean Air Act gives California the authority to adopt and enforce emissions regulations after receiving a waiver from the EPA. California has separate authority and standards for these vehicles under their Low Emissions Vehicle II (LEV II) program. The vehicles in question were certified to both the Federal Tier 2 and 3 standards and the California LEV II and III standards.

  1. What happens to the consent decree now that it is filed with the court? What is the timing? What happens next in the litigation?

The United States and California consent decrees were filed on January 10, 2024, in the U.S. District Court for the District of Columbia. A notice of the settlement will be published in the Federal Register requesting comments for 30 days. The Department of Justice (DOJ) will consider all comments received and will consult with EPA, the California Air Resources Board (CARB), and the California Attorney General’s office to determine whether the comments present reasons for withdrawing the settlement.

If, after this consideration, DOJ still views the settlement as being in the public interest, they will file a motion asking the court to enter the consent decree as a final judgment. Once the Court approves the consent decree, the requirements to which Cummins has agreed must be implemented on the schedule outlined in the settlement.

Information on providing comments and the settlement documents will be available on DOJ’s Proposed Consent Decree web site after the Federal Register notice is published.

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Last updated on January 10, 2024