Beyond the Vehicle-to-Parts Ratio: A Four-Dimensional Value Carrier Framework for Diagnosing OEM–Supplier Coordination in China’s Electric Vehicle Clusters

The concept of automotive components, centred on manufacturing output, no longer captures the software, data and computing power assets that determine advantage in software-defined electric vehicles. Taking China as its setting, this paper asks what a component is once value is generated jointly by parts, code, information and computation. The vehicle-to-parts ratio, it argues, has become unusable: the 2025 revision of sub-national vehicle production accounting removed the comparability of city-level series, and components are reported inside a single manufacturing aggregate in which intangible value is invisible. The paper develops a four-dimensional framework—hardware, software, data and computing power carriers—and a collaboration ecosystem index with published proxy indicators, a five-point coding rubric and the evidence item behind every code; two analysts coded the five city cases independently and agreed on 18 of the 20 cells (Cohen’s κ = 0.82). Applied to Shanghai, Shenzhen, Chongqing, Hefei and Guangzhou, the codes distinguish four coordination modes by binding constraint rather than by total score: Shanghai is constrained by software, Shenzhen by conventional hardware, Chongqing by data and software jointly, Hefei by software, and Guangzhou, which fits no mode, by software and computing power together. Because the four dimensions are not substitutable, the index reports a profile; where a scalar is required, the equal-weight mean (2.50–4.25) and the minimum (2–3) order the cities differently and collapse the three leaders into one grade. A panel of eight listed Tier 1 suppliers shows operating margins diverging over 2021–2024: the two system integrators gain 3.0 and 5.2 percentage points while the six specification-taking suppliers remain within half a point of their starting level. Coordination shifts from local sourcing to capability procurement, with Tier 0.5 integrators the most consequential structural change.