Munich - A former top executive at Audi on Tuesday pleaded guilty over the "dieselgate" emissions-cheating scandal that rocked parent company Volkswagen, after a lengthy trial.
Wolfgang Hatz and two other colleagues had arranged the installation of banned software to rig emissions in diesel vehicles, his lawyer told the Munich district court.
Hatz is expected to receive a reduced sentence for confessing.
It is not yet clear whether former Audi CEO Rupert Stadler - the main defendant in the case, and the first auto boss in Germany to stand trial over the scandal - will also enter a guilty plea.
German car giant VW - whose brands include Porsche, Audi, Skoda and Seat - admitted in September 2015 that it had installed software to rig emissions in 11 million diesel vehicles worldwide.
The so-called defeat devices made the vehicles appear less polluting in lab tests than they were on the road.
On Tuesday, Hatz's lawyer said the defendant "recognised and accepted" that in Germany the software would be considered an illegal defeat device and could also violate American laws.
The former executive - who was head of engine development at Audi, and later research and development chief at Porsche - regretted that he had not acted responsibly.
After a trial that has already run two and a half years, Judge Stefan Weickert said his admission was a "turning point".
Hatz's confession came after the court in March proposed suspended sentences if the defendants admit guilt.
If convicted, the accused had faced up to 10 years in jail.
The court and defence now favour a suspended sentence of 18 to 24 months and a 400 000 euro (R8.04 million) fine for Hatz, although the prosecution has objected.
A hearing is expected to take place behind closed doors later on Tuesday over the role of Stadler, the judge said.
The Audi boss has so far denied the charges against him - fraud, falsifying certifications and false advertising.
But a suspended sentence and fine are also being considered for Stadler if he confesses.
An Audi engineer likewise on trial reached a deal Tuesday for a suspended sentence and fine.
Volkswagen has always insisted that the diesel trickery was the work of a handful of lower-level employees acting without the knowledge of their superiors, but prosecutors dispute this.
The "dieselgate" saga has cost VW billions of euros in fines, legal costs and compensation to car owners - mainly in the United States.
Agence France-Presse