结合PC200－5挖掘机发动机不熄火故障的实例，依据故障排查步骤，对发动机油门控制器进行了故障诊断，并对电子控制式发动机的故障原因和诊断方法进行了分析。 Combining with the example of non-stop failure of engine in PC200-5 excavator, fault diagnosis of engine throttle controller was carried out according to troubleshooting steps. The causes of fault and diagnosis of electronically controlled engine were analyzed.