In the age of digital technology cars will have to exceed their former functionality as a tool for transportation to survive as status symbols. One feasible approach is to provide valuable digital services based on car sensor data which currently is used for the sake of driving only. Hence the ‘quantified self phenomenon’ can be transferred to modern cars - becoming ‘quantified cars’. The paper provides insights into the quantified car phenomenon and explores the approaches of car manufacturers and tech start-ups on their journey to develop novel digital services and sustainable business models. At the moment, cars are an ideal playground for innovative US tech start-ups backed with risk capital to establish new ecosystems following the examples of Google and Facebook. In contrast to that, especially German-speaking car manufacturers have been rather reluctant to reap the value of ‘their’ car operation data in delivering successful digital services to stakeholders. However, two recent reports from ‘Verband der Automobilindustrie’ (VDA) – the German automotive industry association – suggest that Original Equipment Manufacturers (OEMs) have to hold a stronger position in the future and may limit the capabilities of third parties to freely access car data. If implemented as described in the VDA reports, then the battle for a car data-service-ecosystem will progress to the next round.