According to German media reports on Wednesday, police officers and prosecutors searched offices at Audi headquarters in the Bavarian city of Ingolstadt, as well as offices in the states of Baden-Württemberg and Lower Saxony.
The subsidiary for luxury cars of German automobile maker Volkswagen is cooperating fully with the investigating bodies, added Audi's spokesperson.
"With these search orders we aim to clarify in particular who was involved in deploying the technology concerned and in the provision of false information to third parties", the Munich prosecutor's office said in a statement, without naming any suspects.
The U.S. authorities ordered the group to withdraw 482 thousand cars of the brands of Volkswagen and Audi sold in the country over the course of the years 2009-2015.
In September 2015, VW admitted that up to 11 million of its vehicles worldwide had software installed that cheats the emissions tests, unleashing the company's biggest crisis ever.
"The path towards clearing up (the emissions scandal) is far from over", Audi CEO Rupert Stadler said on Wednesday.
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These include Bayern Munich, Liverpool, Arsenal, PSG and Barcelona with each of these clubs believed to be eyeing midfield reinforcements in the summer.
Volkswagen has issued a global recall of all vehicles affected by the diesel manipulation and has pleaded guilty to conspiracy to commit fraud in the US, agreeing to pay fines, penalties and consumer compensation of around $25 billion.
Peter Mertens, senior vice president for r&d at Volvo Car Corp., will take up his position as head of technical development at Audi on May 1, the CEO said, replacing former r&d boss Stefan Knirsch, who left the manufacturer in connection with the emissions scandal.
The engine is said to be used in several auto models of VW, Audi as well as Porsche.
Audi past year increased its diesel scandal-related provisions to 1.63 billion euros and has said it does not expect to have to do so again.
This is the first raid of Audi since VW's diesel scandal broke out in 2015.
More than two million Audis had the manipulated software, including more than half a million in Germany alone.