A BMW X5 sports utility vehicle with a N54 mileage of about 90 thousand km, with a mileage of about N54. User response: when the vehicle is speeding up, the engine fault light is on. Inspection and analysis: the maintenance staff test found that when the car was driving at 60 km/h, if the engine was speeded up, the engine power was detected by the greasy detection engine control unit, and the fault code 29F2 - the oil pressure abnormal of high pressure part of the fuel oil and the abnormal oil pressure of the low pressure part of the 2A2D---- fuel oil. When the engine is idle, observe the oil pressure data, the low pressure is 500 kPa, the high pressure is 4 MPa, normal. Road test showed that the oil pressure of the low pressure part dropped to 230 kPa at high speed, and the high pressure reached 17 MPa. Although the oil pressure of the high pressure part is slightly lower, it will not affect the work of the engine. But from the low pressure point of view, the oil pressure is obviously low, which will lead to insufficient oil supply. It is observed that the speed of the low-pressure oil pump motor is rapidly accelerated. It is found that the speed reached 7000 r/min, which is near the upper limit of the speed. This indicates that the low efficiency of the low pressure oil pump is unable to meet the large flow of fuel supply. Troubleshooting: after the replacement of low-pressure fuel pump trial run, when the acceleration is low, the pressure is maintained at 500 kPa, and the high pressure reaches 20 MPa, which fully meets the design requirements. Look at the speed of the low-pressure oil pump, which has not been more than 4500 r/min, indicating that the new oil pump's efficiency is very high. The test confirms that no matter how fast the engine fault lights are, the engine failure lights will not turn on.