Adopting Model-Based Development (MBD) in automotive software becomes necessary because it provides a rigorous development process. As the increase in the number of software components (SWCs) and their interactions, modifications to one part of the software might impact other parts due to the high coupling of SWCs. Developing an automated software refactoring technique to implement high cohesion and low coupling of software is necessary. Software refactoring usually contains code refactoring and architecture refactoring. Code refactoring only modifies the code inside the SWCs without changing its original functionality and external behavior, whereas current architecture refactoring does not consider the interaction weight (strength) between SWCs.In this study, we propose a weighted community division algorithm called Weighted-Girvan-Newman (W-GN) for software architecture refactoring. W-GN algorithm refactors the architecture by dividing SWCs into modules based on the interaction weights of SWCs. We further develop an automated architecture refactoring tool called AutoToolMD. This tool assists engineers in improving development efficiency and ensures the architecture aligns with the requirements of high cohesion and low coupling. Evaluations show that W-GN indicates more suitable modularity values than the traditional Girvan-Newman (GN) algorithm because the former can better reflect the real architecture with interaction weights. We apply AutoToolMD to automatically refactor architecture in automotive industry practice. Case study with the Zone_B PwrSplyMngt and Zone L_Lock modules in the Honda zone control software shows that AutoToolMD effectively refactors architecture with a significant improvement in testing efficiency and readability.