EPA and the California Air Resources Board (CARB) have both initiated investigations based on Volkswagen’s alleged actions. The NOV covers approximately 10,000 diesel passenger cars already sold in the United States since MY 2014. In addition, the NOV covers an unknown volume of 2016 vehicles.

These alleged violations are in addition to the NOV issued on 18 September and the ongoing investigation by EPA alleging a defeat device on certain 2.0-liter engines for MY 2009-2015 vehicles. (Earlier post.)

Following the 18 September NOV issued for 2.0 liter engines, on 25 September EPA initiated testing of all 2015 and 2016 light duty diesel models available in the US using updated testing procedures specifically designed to detect potential defeat devices. That testing led directly to the alleged violations covered under today’s NOV. The NOV is based on vehicle emission testing performed by the EPA’s National Vehicle and Fuel Emissions Laboratory, CARB’s Haagen-Smit Laboratory, and Environment Canada’s River Road Laboratory.

When this software determines the vehicle has begun the FTP 75 Federal emission test procedure, it directs the vehicle to employ a low NO_x temperature conditioning mode. A status bit in the software indicates that a “temperature conditioning” mode is active. In this low NO_x temperature conditioning mode, the vehicle operates under a number of emission control parameters, including injection timing, exhaust gas recirculation rate, and common rail fuel pressure in such a way that the parameters yield low engine-out NO_x emissions and high exhaust temperatures. The high exhaust temperature heat the selective catalytic reduction system (“catalyst”) and improve the catalyst’s ability to reduce tailpipe NO_x emissions. In this low NO_x temperature conditioning mode, the combination of low engine-out NO_x and improved catalyst performance results in tailpipe NO_x emissions that are below the applicable emissions standard.

However, the software employs a “timer” that coincides with the low NO_x temperature conditioning mode. At exactly one second after the completion of the initial phases of the FTP 75 Federal emissions test procedure (1,370 seconds, which is when the vehicle would normally be turned off), this software directs the vehicle to cease low NO_x temperature conditioning mode. The “temperature conditioning” status bit switches to zero, and a second status bit indicates the activation of “transition to normal mode.” In this “normal mode,” the emission control system is immediately less effective. Compared to the low NO_x temperature conditioning mode, the vehicle employs a different injection timing, exhaust gas recirculation rate, and common rail fuel pressure. This yields higher levels of NO_x from the engine and reduced exhaust temperatures.

In addition, when the vehicle starts under conditions that the software determines are not the beginning of the FTP 75 Federal emission test procedure, the vehicle does not use the low NO_x temperature conditioning mode at all. Instead, the emission control parameters are set consistent with the “normal mode.”

In sum, as soon as the vehicle senses that it is not being tested, it used “normal mode.” In “normal mode,” tailpipe emissions of NO_x are up to 9 times the applicable NO_x standard levels, depending on model type and type of drive cycle (e.g., city, highway).

—EPA 2 November NOV

VW’s software on these vehicles includes one or more Auxiliary Emission Control Devices (AECD) (earlier post) that the company failed to disclose, describe and justify in their applications for certificate of conformity for each model, EPA said. (AECDs are not prohibited, but they must be disclosed.) Every manufacturer must apply to EPA for and be approved for a certificate of conformity for each model, each year otherwise it is illegal to introduce the cars into commerce. An AECD designed to circumvent emissions test is a defeat device.

In his prepared testimony for the House Committee on Energy and Commerce Subcommittee on Oversight and Investigations hearing in October, Michael Horn, President and CEO of Volkswagen Group of America, said that VW’s emissions control strategy also included a software feature that should have been disclosed to and approved by the agencies as an auxiliary emissions control device (“AECD”) in connection with the certification process. As a result, Horn said, Volkswagen withdrew the application for certification of its model year 2016 vehicles. The company was working with the agencies to continue the certification process, he added.

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. The Clean Air Act also prohibits manufacturers’ making and selling vehicles equipped with defeat devices that reduce the effectiveness of the emission control system during normal driving conditions. By making and selling vehicles with defeat devices and by selling vehicles with higher levels of air emissions than were certified to EPA, Volkswagen allegedly violated two important provisions of the Clean Air Act.

VW may be liable for civil penalties and injunctive relief for the violations alleged in the NOV. VW will have an opportunity to respond to the allegations contained in the NOV.

It is Volkswagen’s responsibility to fix the vehicles’ emissions systems, EPA said. Although these vehicles have emissions exceeding standards, these violations do not present a safety hazard for car owners and drivers and the vehicles remain legal to drive and resell. Owners of vehicles of these models and years do not need to take any action at this time.