Abstract: As the penetration rate of new energy vehicles continues to rise, the pressure on after-sales maintenance also increases. This paper takes the BYD Qin EV as an example to elucidate the working principles of the keyless entry system and keyless start. It introduces a combination fault case of the keyless start system in Oin EV, and in the diagnostic process, it provides a detailed description of the elimination process of the combination fault from the perspectives of fault symptoms, fault analysis, repair manual consultation, diagnostic testing, and fault mechanism. The results show that the diagnosis method can quickly eliminate faults and improve efficiency, and can provide reference for teachers, students and after-sales maintenance practitioners in the maintenance teaching process.

Key words: Qin EV cars; keyless start malfunction; fault diagnosis

摘要： 随着新能源汽车的渗透率不断升高，售后维修的压力随之增大。文章以比亚迪秦 EV 为例，阐述了无钥匙进入系统和无钥匙启动的工作原理，引入秦 EV 无钥匙启动系统组合故 障案例，在诊断过程中，从故障现象、故障原因分析、维修资料查阅、诊断测试、故障机理 五个方面详细的介绍了组合故障的排除过程。结果表明，该诊断思路能够快速排除故障，提 高效率，可为职业院校师生和售后维修从业人员在维修教学过程提供借鉴意义。

关键词: 秦 EV 轿车；无钥匙启动失效；故障诊断