Automotive Fleet
MenuMENU
SearchSEARCH

VW, Audi Diesels Circumvented Clean-Air Regs

Audi and Volkswagen four-cylinder diesels used software to circumvent federal emissions standards, the U.S. Environmental Protection Agency has alleged.

by Staff
September 18, 2015
VW, Audi Diesels Circumvented Clean-Air Regs

Photo of 2015 Golf TDI engine courtesy of VW.

1 min to read


Photo of 2015 Golf TDI engine courtesy of VW.

Audi and Volkswagen four-cylinder diesels used software to circumvent federal emissions standards, the U.S. Environmental Protection Agency has alleged.

The cars from the 2009 to 2015 model years included a "defeat device" — a sophisticated software algorithm that detects when the car is undergoing official emissions testing and turns on full emissions controls during that test, according to an EPA violation notice issued Sept. 18. This would violate the Clean Air Act.

Ad Loading...

The allegations cover about 482,000 models, including the Jetta TDI, Beetle TDI, Golf TDI, and Audi A3 TDI. The Passat TDI is affected from the 2014-MY and 2015-MY.

“Using a defeat device in cars to evade clean air standards is illegal and a threat to public health,” said Cynthia Giles, assistant administrator for the EPA's Office of Enforcement and Compliance Assurance.

In a separate action, the California Clean Air Resources Board has issued an In-Use Compliance letter. CARB has initiated its own investigation in addition to the EPA probe.

"Our goal now is to ensure that the affected cars are brought into compliance, to dig more deeply into the extent and implications of Volkswagen's efforts to cheat on clean air rules, and to take appropriate further action," said Richard Corey, CARB executive officer.
By using the defeat device, the cars will emit nitrogen oxides (NOx) at up to 40 times the regulatory standard during normal operating conditions, according to the EPA.
Volkswagen must now offer a fix for affected models, which remain legal to drive and resell. Volkswagen had not commented publicly on Sept. 18.
EPA and CARB uncovered the defeat device software after independent analysis by researchers at West Virginia University, working with the International Council on Clean Transportation, a non-governmental organization, raised questions about emissions levels. The agencies began further investigations into the issue. In September, after EPA and CARB demanded an explanation for the identified emission problems, Volkswagen admitted that the cars contained defeat devices, according to EPA.
Read the EPA's full release here.

More Green Fleet

Sketch of chassis cab truck.
Green Fleetby Chris BrownMarch 9, 2026

Startup ZMD Motors Developing Electric Conversion for Ram 5500 Work Trucks

Detroit-based company says it has begun early development of a system to convert internal combustion Ram 5500 chassis-cab trucks to electric power.

Read More →
SponsoredFebruary 26, 2026

MOVING ON FROM DEBATE: A Guide for Fleet Managers Who Just Want To Get Electrification Done

Fleet managers are done with the debate—and focused on execution. Learn how to build a practical electrification strategy that aligns infrastructure, operations, and financing while keeping costs controlled and deployment scalable with support from Blink Charging. Discover how smart planning today positions fleets for long-term performance and ROI.

Read More →
EV charging symbol
Green Fleetby Chris BrownFebruary 12, 2026

U.S. EV Adoption Is Climbing, but Commercial and Passenger Markets Diverge

New industry group data revealed that light-duty electric vehicle sales are hitting record market share and volumes, while commercial EV volume dipped. What’s driving the fluctuations?

Read More →
Ad Loading...
SponsoredFebruary 6, 2026

Hybrids: Electrification Without the Challenges

For fleet managers, fuel is one of the biggest line items in the budget — and it's one hybrids can shrink without changing how your people work. Download the eBook to see the numbers, understand the technology, and get a step-by-step guide to making the switch.

Read More →
A side view of the yellow, blue, and red Slate Auto electric pick-up truck and SUV
Upfittingby Martin RomjueDecember 8, 2025

How To Upfit Electric Work Trucks and Vans

The biggest challenge lies in balancing additional equipment and accessories with EV battery capacity and range.

Read More →
Green Fleetby Martin RomjueDecember 4, 2025

How Fleets Can Adjust Approaches To EV Adoption

With the expiration of federal incentives, EV success now hinges less on government policy and more on discounts, battery tech progress, increased range, and broader infrastructure.

Read More →
Ad Loading...
Panelists on stage at FFC.
Fleet Forwardby Martin RomjueOctober 29, 2025

Despite World Troubles, Forward Thinking Guides Fleets

Fleet operators shared their challenges during an annual conference that embraced the latest advances across all aspects of running private- and public-sector vehicles.

Read More →
Illustration of GM Energy’s vehicle-to-home system showing an electric truck connected to home power storage, the grid, and GM Energy Cloud through the myOwner app.
Green Fleetby News/Media ReleaseOctober 28, 2025

GM Energy Details Partnerships and Targets for Public Charging Build-Out

EVgo, Pilot, ChargePoint and IONNA named; goal is 35k GM-invested DC stalls by 2030, with customer-experience upgrades at sites.

Read More →
Chart showing September 2025 EV sales. New EV sales totaled 147,716 units, up 44% year over year, and used EV sales hit 40,569 units, up 76%, marking strong third-quarter performance.
Green Fleetby News/Media ReleaseOctober 23, 2025

Q3 Electric Vehicles Sales Hit Record High

EV buyers took advantage of the final federal tax credit days, while average prices edged up for new EVs and continued to decline for used models.

Read More →
Ad Loading...
A green vertical bar graph chart showing the rises and dips in quarterly EV sales since early 2022.
Green Fleetby News/Media ReleaseOctober 10, 2025

EV Sales Hit Record in Q3 Before Incentives Expire

But most OEMs record low-volume sales, which means EV profitability remains a distant dream for nearly every automaker.

Read More →