故障现象一辆原装进口的日产贵士(QUEST)车(采用VG30E型发动机和自动变速器),因出现发动机偶尔加速不良,发动机动力不足故障而进厂维修。故障诊断首先对发动机电控单元的供电与搭铁情况进行仔细测量,一切正常;接着又分别对各主要传感器及其线路进行测量,发现状况也均良好;连接故障检测仪读取故障代码,结果各系统内也无故障代码储存。连接示波器对曲轴位置传感器、凸轮轴位置传感器和转速传感器进行波形测 Symptom An imported QUEST car (with VG30E engine and automatic transmission) was put into service due to occasional poor acceleration of the engine and insufficient engine power. Fault diagnosis First of all, the engine ECU’s power supply and ground conditions were carefully measured, all normal; then the main sensor and its lines were measured and found that the situation is also good; fault detector connected to read the code, the results The system also has no fault code stored. Connect the Oscilloscope to Crankshaft Position Sensor, Camshaft Position Sensor and Speed ​​Sensor Waveform Measurement