This article studies how product architecture affects value chain design in automotive parts industry. Product architecture, the scheme by which functional elements of a product are allocated to physical components, underlies the design of value chains in industries. Through examining the case of center panel units, we found that modularization of the architecture changes partition of tasks and domains of value creating activities among suppliers. The case illustrates that as center panels are modularized, the assembler outsource major processes of developing and manufacturing the center panel units to the module supplier (Tier 1). The module supplier leads product development activities with close cooperation with the assembler and Tier 2 suppliers, sub-assembles components provided by Tier 2 suppliers, and delivers completed units to factories of the customer firm. Although modularization improved quality of the product and greatly reduced direct labor inputs on the final assembly line, it has brought about unexpected deficits in some parts of the value chain. For the sake of adapting to changing product architecture, the study suggests suppliers develop institutional instruments to facilitate restructuring value chains, strategically re-position their activities over the value systems, and activate organizational learning taking into account of interactions of value activities.