Audi is running a voluntary recall of up to 850,000 diesel cars worldwide to install new software on V6 and V8 TDI engines.

Audi says the voluntary recall will further improve vehicles’ emissions in real driving conditions beyond the current legal requirements.

The carmaker said the update will further improve the car’s emissions in real driving conditions beyond the current legal requirements and added that it is “convinced that this program will counteract possible bans on vehicles with diesel engines”.

The number of cars affected in each market has not been announced yet, with more details expected by 2 August, but the carmaker has said the updates will be free of charge.

The programme is taking place in close consultation with Germany’s Federal Motor Transport Authority (KBA), covering affected Euro 5/6 engines in Europe and other markets outside North America.

Last week saw Daimler announce that it is to offer a NOx-reducing software update for 3m diesels, said to curb harmful nitrogen-oxide (NOx) emissions in real-world use, with details of the number of UK cars affected by this action still to be announced.

The Audi announcement follows a report from Der Spiegel magazine last week alleging possible collusion between Volkswagen, BMW and Daimler over technology relating to exhaust gas measures on diesels. The report claims the carmakers agreed to fit smaller AdBlue tanks that do not provide adequate exhaust gas treatment – the allegations have been categorically rejected by BMW, which has added that its diesel vehicles employ a combination of various components to treat exhaust emissions and no upgrades are needed on its Euro 6 vehicles. However, BMW has confirmed its commitment to conduct a voluntary software upgrade of suitable Euro 5 diesel passenger cars at no cost to customers.

Meawhile Audi said its work on “intensively examining all diesel concepts for any irregularities” in recent months has seen it cooperating closely with the authorities and reporting to them, in particular the Federal Ministry of Transport and the Federal Motor Transport Authority (KBA).

The carmaker added: “Audi is aware that the investigations by the KBA have not yet been concluded. If those investigations result in further consequences, Audi will of course quickly implement the required technical solutions in the interest of its customers as part of this EU5/EU6 retrofit program.”

According to Cap HPI, the recalls by Daimler and Audi are unlikely to prove a major factor in future vehicle resale values.

Andrew Mee, senior forecasting editor (UK), said: “Recalls are fairly common and cover a host of fixes. The recent headlines made by Mercedes and Volkswagen Group are understandable given the level of news coverage on the diesel issue. However, the main drivers of future values are still based around available volumes and potential demand in the market as a whole.”

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