Volkswagen says it will recall up to 11 million vehicles in an attempt to move on from the scandal over attempts to cheat tests involving its diesel engines.
New chief executive Matthias Mueller said the German manufacturer will ask customers with some diesel models to come in "in the next few days" for modifications.
Those that contained illegal software will have to be refitted, the company announced - a move which some analysts have said could cost more than $6.5bn.
It comes after Volkswagen was forced to apologise last week when it was discovered it had developed the software in order to trick emission tests in the US for some of its diesel models.
Mr Mueller told a closed gathering of top managers at the company's Wolfsburg headquarters: "We are facing a long trudge and a lot of hard work.
"We will only be able to make progress in steps and there will be setbacks."
On Monday, Audi said 2.1m of its cars were fitted with the same emission cheating software. Skoda has also said that 1.2 million of its cars are involved.
VW had previously said that 5 million of the vehicles affected are those under its own marque. SEAT has now said 700,000 of its cars are involved.
Volkswagen is understood to have suspended the research and development heads of Audi, VW's core passenger car division and sports car maker Porsche. VW owns Audi and Porsche.
German prosecutors also opened an investigation against former Volkswagen CEO Martin Winterkorn as a result of the scandal.
Sweden's chief prosecutor told Reuters on Tuesday he was considering whether to start a preliminary investigation into Volkswagen.
The vehicles affected are those with EA 189 engines, that were required to meet the EU5 (Euro 5) standards that came in after September 2010.
Cars with EU6 engines, which were required by September 2015, are said to be unaffected.
Volkswagen has yet to say how many vehicles might be affected in the UK.
Audi said that some versions of the A1, A3, A4, A5, A6, TT, Q3 and Q5 are among those that were fitted with the diesel engines in question.
Refitting 11 million cars would be one of the biggest recalls in history by a single manufacturer, similar in size to that by Toyota between 2009 and 2010 over acceleration problems.
By 1pm UK time, Volkswagen shares were down 0.6% at €98.6, having been at nearly €170 some two weeks ago.
