故障现象一辆2010款新赛欧SGM 7120 MT车,车主反映该车在挂入倒挡时,燃油表指针慢慢归零,发动机抖动,冷却风扇常转,故障灯点亮,发动机熄火,不挂倒挡或挂倒挡时拔掉倒挡开关均不会出现该故障现象。故障诊断首先确认车辆故障现象属实,用故障检测仪检测进入发动机系统,有故障代码存储(表1)。通过对发动机系统电路(图1)进行分析,燃油表的供电电源由发动机ECM提供。将点火开关置于ON位,燃油表指针开始慢慢回零。根据图1用万用表 Failure phenomenon A 2010 new Sail SGM 7120 MT car owners reflect the car into the reverse gear, the fuel gauge pointer slowly zero, the engine jitter, cooling fan rotation, the fault light is lit, the engine flameout, do not hang Reverse gear or reverse gear pulled out when the reverse switch will not appear the fault phenomenon. Fault diagnosis First confirm the vehicle fault phenomenon is true, with the fault detector test into the engine system, fault code storage (Table 1). By analyzing the engine system circuit (Figure 1), the power supply to the fuel gauge is provided by the engine ECM. Turn the ignition switch to the ON position, and the fuel gauge hands begin to slowly return to zero. According to Figure 1 with a multimeter