The chairman of embattled carmaker Volkswagen says a chain of errors led to the emissions scandal and that its top priority is winning back trust.
Speaking at a news conference, Hans Dieter Poetsch said: "We are talking here not about a one-off mistake but a chain of errors."
He said VW would be "relentless in seeking to establish who was responsible" for the scandal.
VW's chief executive said it was "fighting for every customer".
But Matthias Mueller said a massive slump in sales had not occurred in the wake of the scandal.
In September, US regulators found some VW diesel cars had a "defeat device" - or software - to cheat emissions tests.