Audi said 2.1 million cars worldwide were fitted with the software that allowed parent Volkswagen to cheat US emission tests.
Some 1.42 million Audi vehicles with so-called EU5 engines are affected in Western Europe, with 577,000 in Germany and almost 13,000 in the United States, a spokesman for Ingolstadt-based Audi said on Monday.
Affected model lines include the A1, A3, A4, A5, A6, TT, Q3 and Q5, the spokesman said.
VW said last week around 11 million cars of its group brands worldwide are affected by the diesel emissions scandal.
R&D chiefs suspended
Volkswagen has suspended the R&D chiefs of its core VW brand, luxury division Audi and sports-car maker Porsche, sources familiar with the matter said on Monday.
The carmaker's supervisory board last Friday agreed to put a number of employees on leave until the details of VW's emissions cheating scandal were cleared up, without providing names.
Reuters reported last Thursday that VW would fire top brand executives as it tries to recover from the scandal.
Audi, VW and Porsche declined comment.