Audi, the luxury brand of scandal-tainted Volkswagen Group, announced on July 21 that they would voluntarily retrofit up to 850,000 diesel cars with new software to improve their emissions performance.

The free program will apply to markets outside the U.S. and Canada, and to vehicles with six- or eight-cylinder diesel engines. The software retrofit—which the company isn’t calling a recall—also applies to Porsche and VW models with the same engines.

“The action will take place in close consultation with Germany’s Federal Motor Transport Agency,” Audi said in a statement. The company added that it “aims to maintain the future viability of diesel engines” and believes its retrofit program “will counteract possible bans on vehicles with diesel engines.”

This follows a similar move by carmaker Daimler. On July 18, that company said it would recall 3 million Mercedes-Benz cars with diesel engines in order to improve their emissions performance. Although Daimler is being investigated in the U.S. and Europe for potentially tampering with emissions test results, it hasn’t been charged with any wrongdoing.

In a different action last year, Mercedes-Benz, Opel, Volkswagen, Audi, and Porsche recalled 630,000 diesel vehicles in Europe after authorities found that real-world emissions were often higher than EU emissions standards.

Diesel vehicles have been under a cloud of smog, so to speak, since Volkswagen admitted that it equipped vehicles with emissions control software that went on in lab testing but turned off while traveling on the road. Some German cities have even called for bans on diesel cars because of pollution concerns.

The news of Audi’s retrofit is having more effect on its stock value this week than it did on July 21 when the news broke. As of July 24 at 3:41 p.m. ET, the stock is selling at $711.30, down almost $6.00 from its five-day high of $719.50, and a good deal lower than its all time high of $723.35.

Photo: ricochet64 /