During real-world testing, German government investigators discovered what they deemed excessive NOx emissions levels, chiefly as a result of emissions reductions systems only working at certain temperature levels.
The full list of cars deemed by the German government to have excessive emissions is: Alfa Romeo Giulietta 2.0; Audi A6 V6 3.0; Chevrolet Cruze 2.0; Dacia Sandero 1.5; Fiat Ducato 3.0; Hyundai ix35 2.0; Hyundai i20 1.1; Jaguar XE 2.0; Jeep Cherokee 2.0; Land Rover Range Rover 3.0; Mercedes-Benz V250 Bluetec 2.0; Nissan Navara 2.5; Opel Insignia 2.0; Opel Zafira 1.6; Porsche Macan 3.0 V6; Renault Kadjar 1.5; Renault Kadjar 1.6; Suzuki Vitara 1.6; Volkswagen Amarok 2.0 and Volkswagen Crafter 2.0.
The announcement follows on from the UK government’s similar investigation, which was presented yesterday, finding levels of NOx emissions were up to six times the prescribed legal limit in lab tests. However, the Department for Transport did not immediately back up its findings by calling for a voluntary recall.
However, following the German government's action, Secretary of State for Transport Patrick McLoughlin said: “I am pleased to hear today’s announcement from Germany that Mercedes, Opel, Volkswagen, Audi and Porsche are able to offer consumers changes to their cars which will reduce emissions. I will be seeking urgent clarification from these manufacturers that they will be offering the same fix to car owners in the UK.”
It is not clear if McLoughlin will also call on the other car makers listed by the German government as having excessive emissions in the real world to take action.
Vauxhall/Opel had already announced in March that it had instigated plans to improve NOx emissions of SCR (Selective Catalytic Reduction) diesel engines.
Meanwhile, Audi announced it will go beyond the formal request for action in Germany and recall 65,700 cars with six-cylinder diesel engines throughout Europe. "Cars will be tooled up with a overhauled software in a voluntary service action," the firm said. "The technology is used in EU5 and EU6 models of production-series Q5, A6 and A8 with a manual gearbox."
The following cars have voluntarily been recalled already in Germany: Audi Q5 (22,000 cars); Audi A6 (29,000); Audi A8 (15,000); Opel Zafira (58,000), Opel Insignia (31,000); Opel Cascada (1000); Mercedes A-Class and B-Class (211,000); Mercedes V-Class (36,000); Porsche Macan (32,000); VW Amarok (70,000); VW Crafter (124,000).
It has not been alleged that any of the manufacturers have broken any legal requirements for emissions. However, the German and UK governments have now asked that the real-world emissions levels, which are outside of European regulatory requirements, should be investigated and improvements to the emissions reductions systems be made.
It is understood the German investigation - as with the UK government's - uncovered concerns regarding the operating temperatures of emissions-reducing recirculation systems and particulate filters. The tests showed that manufacturers shut down the filter systems at different temperatures in order to prolong the life of the parts involved.
It has been reported that Mercedes diesels shut down the EGC after treatment systems at 10deg C while Opel’s is shut down at 17deg. This means that, while the systems would run at full effectiveness in the official laboratory emissions tests, they would regularly not be effective in everyday use.
In response to the announcement, Daimler, owner of Mercedes, said the test results do "not indicate the use of non-permissible software". It added there were technical reasons for deviations from the certified values and that it welcomed the EU's forthcoming introduction of Real Driving Emissions (RDE) test methods.
Until now, Mercedes had only said it would offer German customers of the A-Class, B-Class and V-Class a voluntary recall. The entry-level engines affected also include the 1.5 dCi Mercedes-sourced Renault engine, which is understood to be affected on the Kadjar model.
A Nissan statement read: "We are aware of the KBA report and its findings relating to the vehicles they tested in the German market. We have no plans at this time to recall any Nissan vehicles mentioned in the report."
A Hyundai statement read: "All Hyundai vehicles tested comply in full with conditions stipulated by European certification regulations. The company is committed to a policy of continuous improvement and will continue to reduce emissions and develop environmentally friendly technologies" but did not specify if remedial work would be done.
The news follows on from Mitsubishi admitting that it had cheated on fuel economy tests in Japan, a raid related to emissions on the offices of Peugeot and a US investigation into diesel emissions at Mercedes.
Last week, VW revealed that it had reached an agreement with a US judge to buy back affected cars in the US and offer owners compensation.