COVESA have established the Central Data Service Playground (CDSP) as a neutral, open environment for experimenting with data-centric architectures across VSS/VISS, cloud backends, and adjacent-industry use cases. With the addition of rule-based semantic reasoning in the Knowledge Layer, CDSP is starting to support deterministic, explainable decision logic that moves beyond scattered IF-ELSE code. However, the current Knowledge Layer Server depends on a single non-open source reasoner, which creates practical barriers for open adoption, long-term evaluation, and reproducible benchmarking across the community. This presentation is a call to action to make CDSP “multi-reasoner ready” by integrating permissively licensed open-source semantic reasoners alongside existing implementations. We will report our initiative (BMW and TU Berlin) in implementing and benchmarking open source semantic reasoners. This initiative aims to provide a minimal Reasoner Adapter interface (rules/ontology loading, incremental updates, query/inference API, and explanation hooks), a shared benchmark harness built around representative VSS/VDM scenarios, and a contribution workflow that lets members plug in new engines and compare them fairly. Attendees will leave with three concrete outcomes: (1) an agreed integration blueprint and backlog for an OSS reasoner option in CDSP, (2) a candidate short-list and evaluation criteria (performance, determinism, deployability, licensing), and (3) a roadmap to turn these contributions into a community-maintained capability that accelerates SDV and fleet-data innovation.