Volkswagen emissions scandal — fraud on emissions tests using a defeat device from 2009 to 2015 by Volkswagen
Volkswagen secretly programmed 11 million diesel vehicles to cheat emissions tests, exposing major regulatory failures in automotive environmental compliance.
Key Facts
- Vehicles affected worldwide
- 11 million
- Vehicles affected in the US
- 500,000
- NOx excess in real-world driving
- Up to 40 times above US standards
- Model years affected
- 2009 through 2015
- Scandal discovered
- September 2015
- Regulatory body that issued notice
- US Environmental Protection Agency (EPA)
By the Numbers
Location
Cause → Event → Consequence
Volkswagen engineers intentionally developed software for turbocharged direct injection diesel engines that detected when a vehicle was undergoing laboratory emissions testing. Outside of test conditions, emissions controls were largely deactivated, allowing the vehicles to emit far higher levels of nitrogen oxides than permitted under US Clean Air Act standards.
In September 2015, the US EPA issued a notice of violation of the Clean Air Act to Volkswagen Group, revealing that approximately 11 million vehicles worldwide had been equipped with defeat device software. The software activated full emissions controls only during regulatory testing, while real-world NOx emissions reached up to 40 times the permitted US limit.
The scandal triggered global investigations, massive financial penalties, and widespread legal action against Volkswagen. It prompted regulators worldwide to re-examine emissions testing procedures and exposed systemic weaknesses in how vehicle compliance is verified, leading to reforms in automotive emissions oversight across multiple countries.
Discovery & Impact
Volkswagen installed defeat device software in ~11 million diesel vehicles to falsely pass regulatory NOx emissions tests while emitting up to 40x the permitted pollutants in real-world conditions.
Exposed critical flaws in laboratory-based emissions testing regimes globally, prompting regulatory overhaul and heightened scrutiny of automotive emissions compliance worldwide.