Dieselgate became the widely used nickname for Volkswagen’s 2015 emissions scandal.
The name combines “diesel,” the fuel technology involved, with the suffix “-gate,” which recalls the Watergate scandal and is often used for major controversies. News organizations and commentators adopted the term as investigations revealed that software controlled vehicle behavior during emissions tests.
Volkswagen’s affected diesel engines could recognize testing conditions and reduce emissions temporarily. In ordinary driving, nitrogen-oxide emissions were substantially higher for the affected vehicles. The U.S. EPA’s September 2015 action turned a technical regulatory issue into a global corporate crisis.
“Dieselgate” refers specifically to the Volkswagen-centered scandal, although regulators later examined emissions behavior across the wider automotive industry. The term should not be confused with the marketing phrase “clean diesel,” which Volkswagen had used to promote some of the affected vehicles.