Mileage of about 90 thousand km, equipped with Honda's own stepless CVT transmission of the 2009 Guangzhou Honda flying degrees. Car owner's reflection: when the car is in the range of 40 to 60km/h, the transmission feels like a car and is very uncomfortable. Customers go to the local 4S store, the customer needs to change the transmission assembly, the pure new transmission is always expensive, so the customer chooses us, and at this time we are involved in the maintenance of the car. Fault diagnosis: after the car, with the customer road test to confirm the failure phenomenon, hang D gear start normal, when 40 to 60km/h gearbox feeling sometimes no, cold car will not appear this fault, the hot car appears the high frequency of the car, slow step on the accelerator pedal, will not appear malfunction, heavy stepping on the accelerator pedal sometimes malfunction, No fault codes were entered into the engine and automatic transmission system with the X431 diagnostic instrument. Before we make the next judgement, we first understand the control form of the transmission, otherwise it is difficult to identify the fault point blindly. First of all, we understand the structure of the flying CVT transmission. The traditional automatic transmission has a fixed transmission ratio due to all the gears, so the vehicle will have the shift impact when the driving force changes and shifts. In contrast, the mechanism of the Honda CVT transmission is simpler. It is connected by two sets of cone wheels and a steel belt, which can drive the engine speed through the change of the diameter between the active and driven cone wheels, so the CVT transmission will not produce the sensations of shrugging at any working condition. The transmission includes a control unit, an oil pump, an electromagnetic valve and a valve body. The transmission control unit will calculate the signal of the engine and driving and working conditions, control the valve body through the solenoid valve, the valve body controls the oil pressure to realize the change of the radius of the cone wheel, and then passes through the gear group, and then drives the wheel to turn. Troubleshooting: we first look at the oil surface oil of the automatic transmission, the oil surface is short, the oil quality is a little bad, the transmission oil is completely replaced, and the test failure is still after the oil is added. The transmission shrug may have the following aspects: (1) the transmission solenoid valve; (2) the wear of the piston cylinder in the transmission; the wear of the steel belt, the insufficient wear of the oil pump oil, the leakage of the tubing; and (3) the failure of the engine part; the power is not excited as the throttle injector is dirty, the ignition coil is damaged, the spark plug ablated or damaged. Bad household gasoline pump damage a battery voltage is too low. We can first put the gearbox and transmission electromagnetic valve on one side, and check the engine, spark plug, ignition coil, battery and gasoline pump in turn without exception, cleaning the throttle, injector and three yuan catalyst, test and troubleshooting. Of course, engine power is caused by other aspects (such as air filter blockage, ignition timing improper, air flow sensor or intake manifold vacuum sensor, coolant temperature sensor, throttle position sensor fault, exhaust gas recirculation device working poorly, cylinder compression pressure too low, or gas matching) It is necessary to make a judgement when the time is out of order, the exhaust is blocked, and the intake manifolds vacuum is obviously low when the engine is loaded. Fault summary: this fault is relatively complex, between 40 and 60km/h makes most of the maintenance personnel considered the transmission failure, resulting in the replacement of automatic transmission, this fault can be from simple to complex, from easy to difficult, as far as possible to reduce the economic losses of customers. We can analyze, the general car in the start and start of the required amount of fuel, engine power at this time does not come out, and in 40 to 60km/h is the engine power torque switching point, at this time will be reflected, in the 60km/h will not be reflected. Most of the flight has 6 ignition coils, and the 3 ignition coils in the inside will have the same problem. If the engine's power is not enough, the fault starts in the D gear and can be truly reflected at medium speed and high speed. Therefore, the general automatic transmission is similar to the above fault (specific fault analysis) on the problem of 2 liters and 3 blocks (concrete fault specific analysis), so as to provide reference and study for the majority of the peers to avoid a bend.