The logo of German carmaker Volkswagen is seen on the front grill of a Passat car in Willmette, Illinois, September 24, 2015.
The logo of German carmaker Volkswagen is seen on the front grill of a Passat car in Willmette, Illinois, September 24, 2015. Reuters/Jim Young

U.S. Volkswagen had sent letters of warning to California owners of diesel-powered Audis and Volkswagens, mentioning about an “emissions service action” affecting their vehicles in April 2015.

Reuters reported that the letters stated that all the owners of diesel-powered cars would need to take the vehicles to the dealers to make sure the emission software installed in the cars were operating efficiently. However, the company did not mention that it was taking such a call to satisfy the government regulators who started to get the hint of the emission testing cheating.

Between 2010 and 2014, all owners of 2-litre diesel engines VW cars, through the letter, were instructed to go to the dealers for a software update needed to fix a malfunction resulting from the indicator light illuminating. The company made it mandatory for all the owners to perform updates to solve the glitch.

“If the [light] illuminates for any reason, your vehicle will not pass an IM emissions inspection in some regions,” the letter stated.

The U.S. Environmental Protection Agency (EPA) found that the laboratory emissions test results and real world pollution from Volkswagen’s diesel cars failed to match. Back in 2014, officials of California Air Resources Board and EPA allowed a voluntary recall of diesel-powered cars but it was delayed for months. Spokesman Dave Clegern from California Air Resources Board confirmed on Wednesday that the letters were sent as a potential solution and were part of the recall. But they failed to work accordingly.

Initially, Volkswagen had agreed to the discrepancies discovered by EPA, saying that it was a simple technical glitch that could be solved without any hassle. The German carmaker has refused to comment on the letter.

Telegraph UK reported that the German government has revealed that secret “defeat devices” were also built into the diesel cars across Europe. However, it remains unclear whether the devices helped cheat the emissions tests in Europe like in the U.S.

“We have been informed that also in Europe, vehicles with 1.6 and 2.0 litre diesel engines are affected by the manipulations that are being talked about,” German Transport Minister Alexander Dobrindt said.

The company was discovered using software that turns on cars’ full emissions control system when it detects an emissions testing whereas the controls remain turned off when the cars are being normally driven. This allows emission of large quantities of pollution rapidly. EPA estimated that the cars belch 40 times greater pollution than mentioned in Clean Air Act. The pollutants are capable of causing serious health problems, including asthma attacks, other respiratory diseases and premature death.

Volkswagen reported that they are trying to set aside 6.5 billion euros (AU$10.40 billion) to cover the charges. Analysts express doubts over it as the company not only faces the charges of the cars that are to be recalled but also regulatory fines, lawsuits, criminal investigations and a possible hit to sales following the crisis.

Contact the writer at feedback@ibtimes.com.au, or let us know what you think below.