Volkswagen Dieselgate: The Emissions Fraud
How Volkswagen installed defeat devices in 11 million vehicles to cheat emissions tests worldwide
The Defeat Device
Between 2009 and 2015, Volkswagen AG installed software in approximately 11 million diesel vehicles worldwide — marketed under the VW, Audi, SEAT, and Skoda brands — that detected when the vehicle was undergoing emissions testing. During testing, the software activated full emissions controls, bringing nitrogen oxide (NOx) output within legal limits. During normal driving, the controls were deactivated, and the vehicles emitted NOx at levels up to 40 times the permitted standard.
The software was a “defeat device” by any regulatory definition: a mechanism designed specifically to circumvent emissions testing. Volkswagen had marketed these vehicles as “clean diesel,” running advertising campaigns emphasizing environmental responsibility while deliberately engineering them to pollute.
Discovery
The fraud was discovered by researchers at West Virginia University (WVU). In 2014, the International Council on Clean Transportation (ICCT) commissioned WVU’s Center for Alternative Fuels, Engines and Emissions to test diesel vehicles under real-world driving conditions. Researchers Daniel Carder, Arvind Thiruvengadam, and their team tested a VW Jetta and a VW Passat using portable emissions measurement systems during on-road driving. The vehicles emitted NOx at 5 to 35 times the legal limit.
WVU reported its findings to the EPA and the California Air Resources Board (CARB). When regulators confronted Volkswagen, the company initially attributed the discrepancy to “technical issues” and offered software updates. It was not until September 2015, after CARB threatened to withhold certification for 2016 models, that Volkswagen admitted to the defeat device.
Corporate Accountability
VW CEO Martin Winterkorn resigned on September 23, 2015. He was later charged in the United States with conspiracy and wire fraud, though he has not been extradited from Germany. In Germany, Winterkorn’s trial on charges of fraud and market manipulation began in September 2021. As of 2025, German courts have issued convictions against several VW engineers and executives, including former Audi CEO Rupert Stadler, who received a suspended sentence.
In the United States, VW engineer James Liang was sentenced to 40 months in prison. VW executive Oliver Schmidt was sentenced to 7 years. Six other executives were indicted but remained outside U.S. jurisdiction.
Financial Consequences
Volkswagen’s total costs related to Dieselgate have exceeded $33.3 billion, including:
- $14.7 billion to settle U.S. consumer and environmental claims (2016)
- $4.3 billion in U.S. criminal and civil penalties (2017)
- Billions in settlements with European regulators and consumers
- Vehicle buybacks, retrofits, and environmental remediation
The scandal triggered investigations into other manufacturers, revealing that real-world emissions deviations — though not always involving deliberate defeat devices — were industry-wide.
Health Impact
A 2017 study published in Environmental Research Letters estimated that the excess NOx emissions from VW’s defeat devices would contribute to approximately 1,200 premature deaths in Europe alone. NOx is a precursor to fine particulate matter and ozone, both of which are linked to respiratory disease, cardiovascular disease, and premature death.
Research Verdict
| Assessment | CONFIRMED |
| Confidence | High |
| Summary | Volkswagen deliberately installed software in 11 million vehicles to cheat emissions tests, then concealed the fraud from regulators and consumers for years |