Volkswagen Polo Facelift 14

The drama surrounding Volkswagen’s diesel-related fiasco continues to escalate, and this one looks set to run and run. The fall-out from the screw-up is likely to be significant – news has just broken that CEO Martin Winterkorn has resigned, and the damage won’t be just limited to that or tumbling shares.

To recap, the German car manufacturer was caught out for having installed illegal “defeat devices” in its diesel-powered cars to help it comply with emissions tests in the US. Earlier in the week, it was reported that the United States Environmental Protection Agency (EPA) had begun lobbying for a recall of roughly 482,000 Volkswagen and Audi cars in the country over the issue, which involved the use of illegal code in software to help these cars pass emissions tests.

The software engaged full emissions control when the cars were put through emissions tests, but deactivated emission control systems in real-world operation away from testing facilities, the result being that cars were emitting “up to 40 times” the permitted levels of nitrogen oxides. The pollutants churned out are understood to be linked to illnesses such as asthma attacks and other respiratory diseases.

Affected vehicles include model year 2009-2015 Volkswagen Beetle, Golf, Jetta, Passat as well as Audi A3 units – all models were equipped with a turbocharged 2.0 litre four-cylinder diesel engine. Fines are expected to come about – initial reports said that automaker could be penalised by as much as US$37,500 per vehicle, and adding it all up would take the total to around US$18 billion.

Volkswagen Winterkorn apology video screenshot

So how did VW allegedly cover up things, and just how did it finally get caught out? According to a report by Wired, diesel vehicles in the US are equipped with a new tech called selective catalytic reduction, which scrubs pollutants before gases are emitted from the tailpipe.

The report explains that the scrubbing system works by spraying a liquid composed of 30% urea and 70% water into a honeycombed chamber within the exhaust path, and this composition chemically converts nitrogen oxides into nitrogen, oxygen, water and small amounts of carbon dioxide, effectively reducing diesel NOx emissions up to 90%.

It was this that gave away Volkswagen’s supposed masking exercise. In 2013, a small non-profit group decided to compare diesel emissions between European models and their respective US version. Together with West Virginia University, the International Council on Clean Transportation (ICCT) trialled three cars equipped with four-cylinder 2.0 litre diesels in the Los Angeles area.

The cars were a VW Jetta and Passat as well as a BMW – the latter was the only one who passed the test. The ICCT team noticed a discrepancy between the figures quoted by Volkswagen during emissions testing and recorded real-world numbers. Surprised by the results, the ICCT reported its findings to both the EPA and the California Air Resources Board (CARB).


Last year, the automaker agreed to address the issue with a voluntary recall after meeting with regulators. Then, in July, CARB performed follow up testing, and the cars failed again — Wired reports that the scrubbing system was present, but wasn’t running most of the time.

Further examination revealed that the emission control systems were inactive during regular use of a vehicle. When active, there’s a trade-off between performance and emissions, and so not running it aided performance but cranked out pollutants.

When it came to emissions testing, the car would behave as stated. The task was achieved by clever – and simple – manipulation of how the sensors responded in relation to input from the steering column, the report stated. During normal driving conditions, the fluctuation in the column as it moved to turning input kept the exhaust output unchecked.

Under emissions testing, however, the steering didn’t move despite the wheels doing so, which provided a trigger for the “defeat device” to turn the catalytic scrubber up to full power, allowing the car to pass the test. Clever, truly, but sometimes you can be too clever, and the price to be paid for being that is high indeed.