The mileage is about 86 thousand km, which is equipped with the Honda L15A1 car in 2007. Soon after the car was started, it was easy to flameout and appeared several times a day. The repair factory did not solve the problem for several days. Finally, it entered the 4S shop for maintenance. Fault diagnosis: 1) first ask the owner, the owner reflects the replacement of the ignition coil and spark plug in the maintenance plant, checking the fuel pressure a little bit low, but using the fuel pump for replacement inspection, the fault remains, indicating that both the ignition system and the fuel system have no fault. 2) use HDS to read the engine fault code and display the normal state. 3) check the engine line and check the plug and the plug of the crankshaft position sensor and camshaft position sensor. 4) according to the analysis of the fault phenomenon, the car will be extinguished automatically after starting, and the fault appears regularly, indicating that it is an intermittent difficult fault and must be related to the engine fuel control. 5) in the power supply circuit of the fuel pump in series a test lamp, at the same time open the ignition switch and close, repeat the action, and observe the flicker of the test lamp at the same time, when the fifth times the failure occurs, the test light has not closed the ignition switch and extinguished, after checking the fuel control line has no fault, preliminary judgement Performance degradation for ECM/PCM. 6) decided to use a good running ECM/PCM to replace, a few days later never appeared similar to the previous phenomenon, indicating that ECM/PCM does have a failure of performance performance. 7) at last, replace the new ECM/PCM for the owner, and after resetting, the engine troubleshooting and maintenance summary: in the maintenance of difficult miscellaneous disease, the use of replacement examination method can improve the efficiency of diagnosis. The car is a typical ECM/PCM engine performance caused by poor engine failure prone.