Volkswagen has blamed a small group of employees for implementing the technology that allowed its vehicles to cheat U.S. diesel emissions tests.
It said also said there was no indication that board members were involved in the affair.
According to VW Chairman Hans Dieter Poetsch, an investigation into the scandal is continuing and it has identified a ‘chain of errors’ that led to the installation of the cheating technology.
He said the engine-development unit remained the focus of investigations.
However, Poetsch admitted that 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.
In November, extreme reduction targets set by its former CEO Martin Winterkorn were said to have put pressure on VW engineers to manipulate the testing regime to demonstrate positive results.
The company hopes to reach agreement with U.S. environmental authorities in the coming days and weeks so it can start to recall affected cars in the country. Cooperation with those authorities was described as ‘excellent’.
"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."
"Based on what we know today, it was a very limited group which acted irresponsibly."
Current chief executive Matthias Mueller has expressed confidence that buyers would get over their reluctance to buy the group's vehicles in the coming weeks.
Mueller said the crisis was an opportunity for VW to introduce long-needed structural change. Since the start of this year, the VW group's executive board has brought in six new members, and top management had been changed at seven of VW's 12 brands.
VW is also planning to bring in a new corporate structure that would be implemented across the group by early 2017.
The company is embroiled in two, separate scandals, regarding the use of devices to cheat both nitrogen oxide and carbon dioxide tests.
Yesterday VW said that the number of vehicles with understated carbon emissions was far lower than the 800,000 initially predicted.