故障现象一辆东风云汽客车(车型为KM6651PA,采用玉柴YC4E国Ⅲ博世高压共轨发动机),出现发动机动力不足,仪表盘上的发动机故障灯点亮的现象。故障诊断对该车进行检查发现,每次用故障检测仪清完历史故障代码后再次检测时,只要油门开度超过42%,故障检测仪的通讯就会马上中断,同时发动机油轨压力泄压阀打开,转速限制在1700 r/min以下,但不会熄火,此时能调得以 Fault phenomenon An Dongfengyun Bus (model KM6651PA, using Yuchai YC4E country Ⅲ Bosch high-pressure common-rail engine), the engine power shortage, the dashboard engine fault light lit phenomenon. Fault diagnosis The car inspection found that each time the fault detector clear the historical fault code again after the test, as long as the throttle opening of more than 42%, fault detector communication will be immediately interrupted, while the engine rail pressure relief Valve open, speed limit at 1700 r / min below, but will not turn off the flame, this time can be transferred to