When the VW scandal broke, the US indicted seven senior executives [1]. Germany did not cooperate. None of these seven were extradited to the US to stand trial.
One more mid level engineer involved in the scandal made the mistake of taking a vacation to Florida. He was arrested in the airport awaiting his flight home to Germany [2]. He was sentenced to 84 months in prison but was let out after serving half of that sentence [3].
[1] https://www.justice.gov/archives/opa/pr/former-ceo-volkswage...
[2] https://money.cnn.com/2017/03/17/news/companies/volkswagen-e...
[3] https://www.autonews.com/automakers/ex-vw-manager-schmidt-ge...
Germany does not extradite its nationals to the US at all. Not sure why would you expect this case to be so special that Germany would break its own laws.
You're stating this very confidently, but I don't think it's a blanket non-extradition policy. In the case of a potential death penalty, it's a clear no, but that's not the case here.
https://www.state.gov/wp-content/uploads/2019/02/10-201.9-Ge...
German constitution, translation to English: - https://www.gesetze-im-internet.de/englisch_gg/englisch_gg.h...
Article 16 (2) No German may be extradited to a foreign country. The law may provide otherwise for extraditions to a member state of the European Union or to an international court, provided that the rule of law is observed.
USA is not a member of European Union nor an international court.