This 2010 Opel 1.7 diesel failed its roadworthiness test because of excessive smoke opacity. The filter had already been cleaned before the vehicle came to AutoChip, but that had not brought the readings within the required range.

The control unit software was checked and the engine calibration adjusted. The car was then tested with an opacity meter during several acceleration runs. The video gives readings of 0.75, 0.63 and 0.62, with an average coefficient of 0.67. No unit of measurement is specified.

After the test, the technician said the car had passed its roadworthiness inspection, and no pronounced black smoke was visible under acceleration. Another vehicle also appears in the video, but this article covers the Opel opacity test.