VW Diesel Emission Scandal Began Last Year

The origins of Volkswagen AG's rapidly expanding diesel emission cheating scandal began in Europe more than a year ago, Bloomberg News reports.

Ironically, it started with an effort to prove diesels were clean. The Berlin office of the International Council on Clean Transportation turned up major discrepancies between official test results and real-world emissions. But it partnered with West Virginia University in the U.S. in hopes of showing VW's diesels were successfully achieving America's tougher diesel emission standards.

Instead, the researchers found similar "shocking" gaps in emission levels. The revelation led to a VW recall last December of nearly 500,000 diesel-powered cars in the U.S. to install a software patch to correct the problem. But by July the California Air Resources Board found the software fix was not successful.

Meanwhile, the Environmental Protection Agency told VW it might not certify the company's 2016-model diesels until the gap in emissions was resolved. Bloomberg says VW continued to offer technical explanations for the problem. But when agency confirmed it would not certify the new models, VW admitted it was cheating on the tests.

According to the EPA, the engine control software was rigged to tighten emission levels when a vehicle was being tested but loosen the controls in on-the-road driving.

The original researchers note the same two-level emission issue could affect VW diesels in other markets such as China. On Monday South Korea said it plans to retest about 5,000 VW diesels in October.