Around 11 million Volkswagen diesel cars worldwide were equipped with "defeat device" software that allowed them to cheat on emissions tests, VW has said.
But initially, it was only confirmed that the cars actually violated U.S. emissions rules.
Now, a laboratory test conducted by the BBC appears to have shown that the software is programmed to make the cars exceed European emissions limits as well.
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VW has not so far confirmed that the software was used to cheat on European tests, but it can do that in reality, a test by the BBC program Panorama showed.
The British news organization initially found that no U.K. emission testing lab was willing to test its European-spec Volkswagen Passat Blue Motion diesel for the network.
So it took the car to an accredited lab in the Czech Republic, and had the proceedings supervised by a retired government vehicle inspector.
2012 Volkswagen Passat TDI Six-Month Road Test
As in the U.S., European government agencies do not regularly test cars for compliance with emissions standards.
Instead, carmakers contract with independent labs--like the one used by the BBC--to conduct the tests.
Cars are placed on a dynamometer and run through a standardized test sequence, the conditions of which can be detected by the software.
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The software keeps the car running within legal limits during the test, but disregards those limits in real-world driving--allowing higher levels of emissions.
The test car passed the standard Euro 5 emissions test that would have been required when it was new.
But then testers tricked the car into thinking it was out of the lab.
2015 Volkswagen Golf TDI SE
They accelerated hard a few times, and ran the Passat up to much higher speeds than were called for under the test rules.
After that, they then ran the entire Euro 5 test cycle again, this time starting with a hot engine. Testing procedures require that the car be started with a cold engine.
This time, the car failed, emitting 435 mg/km of nitrogen oxides (NOx)--well above the legal limit of 180 mg/km.
MORE: U.S. Emission Tests Are Unrealistic, But European Testing Is Far Worse
When shown the results, Volkswagen confirmed that the software had been tricked into thinking the test was over, and changed the vehicle's operating parameters.
For the second test, the car "did not recognize this as a test condition and changed its emissions strategy," VW told the BBC.
Volkswagen has so far set aside $7.3 billion to deal with the full scope of the scandal, but financial analysts suggest that it will likely spend far more than that on government fines and consumer buybacks or repairs in dozens of markets.
[hat tip: George K]