Volkswagen’s premium carmaker Audi announced its biggest management reshuffle in years on Monday as it seeks a fresh start in the aftermath of the diesel emissions scandal.

Audi, which is the biggest contributor of profits to VW, said it was replacing finance chief Axel Strotbek, production chief Hubert Waltl, human resources head Thomas Sigi and sales chief Dietmar Voggenreiter, effective Sept. 1. Chief Executive Rupert Stadler, who has come under fire from the media and unions for his handling of the group’s emissions scandal, remains in office, as expected. The statement gave no reason for the shake-up.

People familiar with the matter had flagged the management reshuffle to Reuters. One said that Stadler had the backing of the Porsche and Piech families that control Volkswagen (VW), which is why his contract was extended by another five years in May. Audi is grappling with car recalls, prosecutor investigations and criticism from unions and managers over the diesel emissions scandal and its performance since news of the affair broke in 2015. Audi admitted in November 2015 that its 3.0 litre V6 diesel engines were fitted with an auxiliary control device deemed illegal in the United States that allowed vehicles to evade U.S. emissions limits.