VW Says it Can Explain Audi Software That Alters Emission Results

Volkswagen AG says it can “clarify” apparent discrepancies in the carbon dioxide emissions of cars and crossover vehicles sold by its Audi unit. The company confirmed over the weekend that the issue has triggered investigations by European and U.S. regulators.

Last week Germany’s Bild am Sonntag reported that California regulators found software in one Audi model that detects when the vehicle is undergoing certification tests and switches to a special gearshifting protocol to reduce CO₂ emissions.

But VW suggested over the weekend that the suspicious software simply addresses a routine testing issue for vehicles equipped with so-called adaptive or programmable transmissions. Such gearboxes “learn” an operator’s driving style and adjust their gearshifting characteristics accordingly. The objective is to deliver the responsiveness the driver demands—from gentle to sporty—while maximizing engine efficiency.

For years carmakers have used adaptive transmissions in everything from economy cars to luxury sedans. VW says the dynamic gearshift programs that control these gearboxes can become confused during emission tests because the vehicle isn’t moving, even though its drive wheels are rotating on rollers.

Unless certain components of the software are switched off during the tests, VW asserts, the control program “can lead to incorrect readings and results that cannot be reproduced.” The company says it will clarify the procedure and “technical background” to KBA, Germany’s transport authority.