Volkswagen has said only a small group of employees were responsible for cheating US diesel emissions tests and there is no indication board members were involved in the scandal.
Chairman Hans Dieter Poetsch on Thursday said investigations into the affair were going well, but the incident was the result of a "chain of errors" and it would take months to say which individuals were to blame.
The carmaker announced that it had agreed steps to improve oversight of engine-software development to avoid any future emissions test manipulations.
"No business justifies crossing legal and ethical boundaries," Poetsch said.
"Even though we cannot prevent misconduct by individuals once and for all, in future it will be very difficult to bypass our processes."
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Volkswagen hoped to reach agreement with US environmental authorities in the next few days or weeks so the company can start to recall affected cars there.
Co-operation with those authorities was described as "excellent".
Despite the scandal, orders so far this year were up by 3.5 per cent and chief executive Matthias Mueller said he was confident buyers would get over their reluctance to buy the group's vehicles in the coming weeks.
VW also said it was planning to bring in a new corporate structure that would be in place across the group by early 2017.
The company was not considering the sale of any units to simplify the group structure or raise money, and said it was happy with having 12 brands.
But executives were still unable to estimate the scandal's legal costs, for which they had so far made no provisions.
Mueller, who has not been to the United States since becoming chief executive after the scandal broke, said he would visit the country after the Detroit motor show in January.
Speaking at a news conference at VW's headquarters in Wolfsburg, Mueller said he would apologise for the situation, but added: "I don't think I will be going down on my knees there ... I will look ahead optimistically and confidently."
Europe's biggest carmaker launched internal and external investigations in September after admitting its deception in the United States.
Up to 11 million cars worldwide have software installed that defeats emissions tests, and the costs to Volkswagen of fixing the cars, paying fines to environmental authorities and dealing with legal challenges are estimated in the tens of billions of euros.
