Mercedes-Benz forced into Dieselgate recall

The German Transport Ministry (KBA) yesterday ordered Mercedes-Benz to recall almost 240,000 diesel-powered cars for alleged emissions cheating.

While Daimler, Mercedes-Benz’s parent company, stridently denied any cheating, the KBA insisted it had found five unauthorised pieces of emissions-cheating software in 774,000 diesel engines across Europe.

“The Government will order 238,000 Daimler vehicles to be immediately recalled Germany-wide because of unauthorised shutoff devices,” the KBA said in a statement.

The main problem models were the big-selling C-Class 220d sedan and wagon, the Vito van and the GLC 220d coupe SUV, the KBA confirmed.

It came on the back of a May missive from the KBA, which ordered Daimler to recall 4923 Vito vans that had been sold despite not meeting compliance regulations, while it “voluntarily” recalled three million cars under KBA pressure to improve emissions performance.

The European Commissioner for Industry, Elzbieta Bienkowska, used the KBA’s action to call for mandatory recalls by Daimler across the 28 EU member states.

Daimler CEO Dr Dieter Zetsche was ordered to appear in front of the KBA late last week and insisted the meetings were “constructive”. This week Dr Zetsche claimed Daimler had found a technical solution to update the software on the offending cars, which he hoped would help the company to avoid a fine.

The software cheat in question is the much-reported “Thermal Switches” which Daimler, Opel, PSA and others have used as a loophole to pass NOx emission requirements at laboratory temperatures.

The system bypasses its full emission controls at cold or hot temperatures to take advantage of the “system longevity” loophole in the emissions regulations. For Mercedes-Benz, that means its cars switched off the emissions controls below nine degrees and above 26 degrees to guarantee its systems would survive over the vehicle’s lifespan.

Daimler has fought for more than two years against being dragged into Volkswagen’s Dieselgate scandal, to the point of threatening journalists who correlated thermal switches with Volkswagen’s cheat. Even today it insisted that “Open legal questions will be clarified in the objection proceedings”.

Six Mercedes-Benz models appeared in environmental lobby group Transport and Environment’s 2016 'Dirty 50' list of diesel cars and SUVs, with the finger pointed at both thermal switches and another hot-restart software loophole.

“Regulatory limits for NOx emissions are also breached by a significant margin when tested in conditions even slightly divergent from those prescribed in the EU test protocol (NEDC),” Transport and Environment insisted.

“The principal reason for such gross exceedances (sic) is that carmakers routinely switch-off technologies that clean up the exhaust when the car is driven on the road, and only operate these fully during the narrow conditions of the tests.

“This is partially to improve official fuel economy figures but is also due to questions about the durability of the emissions treatment systems carmakers have used – specifically exhaust gas recirculation systems that pump hot exhaust gases with a lower oxygen content back into the cylinders to lower production of NOx.”

Mercedes claims its latest diesels, particularly its new 3.0-litre inline six-cylinder motors, have moved beyond the need for thermal switches by pulling the NOx catalysts much closer to the exhaust manifold.

Yet T&E’s 2016 survey showed Mercedes-Benz’s average diesel fleet emitted 6.4 times the EU’s NOx emissions limits, rating as worse than Ford, Kia, Toyota, Honda, Audi, Mazda and Jaguar Land Rover.

BMW and, surprisingly, Volkswagen were the best at real-world emissions, emitting around twice the legal limit in the real world.