Audi A6 50 TDI quattro diesel AWD automatic

Our verdict

The Audi A6 is a full-size executive limousine and is tested here with a top-of-the-line three‑litre turbocharged diesel engine, providing 210 kW peak power. Its lighter and less powerful variants might perform better in Green NCAP but this one, like most other fossil fuelled cars, has limited potential for minimizing greenhouse gas emissions, even though the diesel powertrain is more efficient than the petrol counterpart. The high mass of two tonnes also makes it more difficult to keep consumption and CO₂ emissions low. However, with about 6‑7 l/100 km, the car presents respectable consumption figures for its type. The performance in the Clean Air Index is impressive, demonstrating unusually low particle emissions and excellent control of the other polluting species. Nevertheless, the Motorway test revealed a serious weakness of the exhaust aftertreatment – under high-power conditions NO_x treatment loses robustness and the emissions rise significantly over Green NCAP gross exceedance thresholds. As a consequence, the total Highway Test result is set to zero and the Audi loses valuable points. Overall, the 50 TDI quattro scores an average of 37% and 2 Green Stars, and could have done better if it were not for the emissions control in the BAB130.