The development of equipment system is a continuous process of solving technical problems, and fault return-to-zero is a normalized work in model development. It is necessary to learn from problems and faults and clarify the general laws and methods for fault return-to-zero. This study focuses on faults and tracks the entire process from fault occurrence to fault resolution. It summarizes the common laws of and general methods for fault return-to-zero in model development from the aspects of definition and values of faults, thinking mode of fault return-to-zero, and methods for fault return-to-zero. Moreover, it explores the four values of faults, four basic concepts of system thinking, and four common methods for fault troubleshooting, and elaborates on the six key links of fault return-to-zero: fault location, fault cause and mechanism analysis, fault recurrence design, improvement measure verification, extrapolation, and extraction of guidelines and inspirations. This study aims to prevent repetitive, simple, and low-level faults that might occur during model development and use, significantly reduce high-level and complex problems caused by insufficient understanding, and achieve complete technical return-to-zero with high quality and efficiency when faults occur.