Under Browning's tenure, Winterkorn blamed U.S. management for a series of problems ranging from a failure to update the Passat model to seemingly prosaic matters such as paint.
On one U.S. test drive in July 2013, Winterkorn spotted a slight bump in the paintwork of a Beetle model. According to one VW source, who declined to be named, the paint thickness exceeded company standards by less than a millimetre, but Winterkorn still lectured engineers about the waste.
On the same trip, he told staff he was unhappy that VW was not offering a shade of red that was selling well on competitors' models. Winterkorn mentioned the issue the following year after Browning had gone. "They should have come and said 'Herr Winterkorn, we must update the Passat'; they should have jumped on my desk," he told Der Spiegel magazine.
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But several former managers in the VW group - whose brands also include Audi, Porsche, SEAT and Skoda - said few executives dared approach Winterkorn.
"There was always a distance, a fear and a respect... If he would come and visit or you had to go to him, your pulse would go up," the former VW executive told Reuters. "If you presented bad news, those were the moments that it could become quite unpleasant and loud and quite demeaning." The executive did not provide specific examples.
Even in public Winterkorn ordered very senior staff around. A video shot at the Frankfurt motor show four years ago gives a glimpse of the man's style. The video, which is posted on YouTube, shows him inspecting a new model from South Korean rival Hyundai, surrounded by a posse of dark-suited managers.
He circles the car, inspecting the locking mechanism on its tailgate, and then climbs into the driver's seat. First he strokes the interior trim, then he adjusts the steering wheel and discovers something that displeases him - it moves silently, unlike on VW or BMW models.
"Bischoff!" he barks in the footage - no first names or honorifics - summoning VW's design chief. "Nothing makes a clonking sound here,"he says grumpily, pointing to the wheel.
Asked about his experience working with Winterkorn, Bischoff told Reuters: "Winterkorn always wanted the best solutions and kept pushing staff to the highest goals, but it would be wrong to portray him as a ruthless, intimidating leader. Of course he went through the roof when something went the wrong way and he didn't only make friends with his temper. But I also experienced him as extremely human with a soft spot for peoples' personal fates."