EPA and California ARB charge Volkswagen with using software defeat device to circumvent NOx testing in 4-cylinder 2.0L diesels
EPA has issued a notice of violation (NOV) of the Clean Air Act (CAA) to Volkswagen AG, Audi AG, and Volkswagen Group of America, Inc. (collectively referred to here as Volkswagen). The NOV alleges that Volkswagen and Audi cars from model years 2009-2015 equipped with 2.0-liter, four-cylinder diesels include software (a “defeat device”) that circumvents EPA emissions standards for NOx. California is separately issuing an In-Use Compliance letter to Volkswagen, and EPA and the California Air Resources Board (ARB) have both initiated investigations based on Volkswagen’s alleged actions.
In response, Volkswagen said that it is cooperating with the investigation, and is unable to comment further at this time. VW may be liable for civil penalties and injunctive relief for the violations alleged in the NOV. The allegations cover roughly 482,000 diesel passenger cars sold in the United States since 2008. Affected diesel models include:
- Jetta (Model Years 2009 – 2015)
- Beetle (Model Years 2009 – 2015)
- Audi A3 (Model Years 2009 – 2015)
- Golf (Model Years 2009 – 2015)
- Passat (Model Years 2014-2015)
Volkswagen would need to initiate the process that will fix the cars’ emissions systems. The alleged violations do not present a safety hazard; the cars remain legal to drive and resell. Owners of cars of these models and years do not need to take any action at this time.
As described in the NOV, software installed in the electronic control module (ECM) on the affected vehicles detects when the car is undergoing official emissions testing. EPA calls this software “the switch”.
The switch senses whether the vehicle is being tested or not based on various inputs including the position of the steering wheel, vehicle speed, the duration of the engine’s operation, and barometric pressure. These inputs precisely track the parameters of the federal test procedure used for emission testing for EPA certification purposes. During EPA emission testing, the vehicles’ ECM ran software which produced compliant emissions results under an ECM calibration that VW referred to as the “dyno calibration”. … At all other times during normal vehicle operation, the “switch” was activated and the vehicle ECM software ran a separate “road calibration” which reduced the effectiveness of the emission control system (specifically the selective catalytic reduction or the lean NOx trap). As result, emissions of NOx increased by a factor of 10 to 40 times above the EPA compliant levels, depending on the the of drive cycle.—EPA NOV
The software produced by Volkswagen is a “defeat device,” as defined by the Clean Air Act.
The Clean Air Act requires vehicle manufacturers to certify to EPA that their products will meet applicable federal emission standards to control air pollution, and every vehicle sold in the US must be covered by an EPA-issued certificate of conformity. Motor vehicles equipped with defeat devices, which reduce the effectiveness of the emission control system during normal driving conditions, cannot be certified. By making and selling vehicles with defeat devices that allowed for higher levels of air emissions than were certified to EPA, Volkswagen violated two provisions of the Clean Air Act, EPA charged.
ARB and the EPA were alerted to emissions problems with these vehicles in May 2014 when the West Virginia University’s Center for Alternative Fuels, Engines & Emissions published results of a study commissioned by the International Council on Clean Transportation (ICCT) that found significantly higher in-use emissions from a 2012 Jetta and a 2013 Passat. For a year following the publication of the study, VW asserted that the increased emissions could be attributed to various technical issues and unexpected in-use conditions. VW then issued a voluntary recall in December 2014 to deal with the issue.
ARB, coordinating with EPA, conducted follow-up testing, which found only a limited benefit from the recall. ARB then broadened the investigation to determine the technical nature of the poor emissions performance and to figure out why the onboard diagnostics were not detecting the problem.
None of the potential technical issues suggested by VW explained the higher test results consistently confirmed during CARB’s testing. It became clear that CARB and the EPA would not approve certificates of conformity fo VW’s 2016 model year diesel vehicles until VW could adequately explain the anomalous emissions and ensure the agencies that the 2016 model year vehicles would not have similar issues. Only then did VW admit it had designed and installed a defeat device in these vehicles in the form of a sophisticated software algorithm that detected when a vehicle was undergoing emissions testing.—EPA NOV
To have a more controlled evaluation of the high NOx observed over the road, CARB developed a special dynamometer cycle which consisted of driving the Phase 2 portion of the FTP repeatedly. This special cycle revealed that VW’s recall calibration did increase Diesel Exhaust Fluid (DEF) dosing upon initial startup; however, dosing was not sufficient to keep NOx emission levels from rising throughout the cycle. This resulted in uncontrolled NOx emission despite the SCR reaching sufficient operating temperatures.
… Several technical meetings with VW followed where VW disclosed that Gen1, Gen2 and the 2015 model-year improved SCR vehicle (known as the Gen3) had a second calibration intended to run only during certification testing. During a meeting on September 3, 2015, VW admitted to CARB and EPA staff that these vehicles were designed and manufactured with a defeat device to bypass, defeat or rend inoperative elements of the vehicles’ emission control system.—ARB letter