A 2010 535GT BMW car with a mileage of about 45 thousand km. The car was unable to start after the overhaul of the accident, and the fan was running at high speed when the ignition switch was at KI.15. Fault diagnosis: the connection ISTA/D diagnosis has a lot of DME fault, check DME found that the two wire harness plug close to the throttle side of the DME plug plug (because the two plugs in the design can be interplugged in the design, so the engine after overhaul the engine is accidentally inserted back. " It is still unable to start again, but the electronic fan is not functioning properly. Diagnosis of "high pressure rail sensor signal is not credible" fault memory, remove the high pressure rail sensor plug, start again can start normally. Troubleshooting: after replacement of high pressure rail sensor, the test is normal and vehicle maintenance is completed. Fault summary: the design of DME plug for N55 engine is different from that of other engines. It is easy to plug in when it is not careful. The consequence is that it will damage the high pressure rail sensor. We should pay attention to it later.