Failure phenomenon: a Audi A62.8 car (equipped with a CVT stepless automatic transmission with a S gear, a transmission model FRZ), and replaced a stepless automatic transmission due to a collision accident. The new replacement of the stepless automatic transmission has a mileage of less than 10 thousand km, which occurs when the vehicle is unable to run when the D gear is idle. When you are walking on the rice, you feel that the vehicle is running out of control and driving back and forth, but the R gear is running normally. The indicator light flickers on the dashboard. Fault diagnosis: after receiving the car, according to the breakdown phenomenon of the indicator light, the fault detection instrument is used to detect the fault of the automatic transmission system. It is found that there are 2 fault codes in the automatic transmission control unit, which are the fault code 1814 one clutch pressure self-adapting to the self-adaptive limit and the fault code 18181. The signal of the hydraulic pressure sensor 1 (GI93) is too large. According to this, the body of the automatic transmission is replaced, but after the valve replacement is reduced, the D gear can sometimes go forward at idle speed, but sometimes it is not normal. The automatic transmission control unit and the automatic transmission oil filter are replaced, but there is no improvement in the fault. Again, the automatic transmission electronic control system is detected, the fault code no longer appears, but the 010 and 011 groups in the dynamic data flow are not normal in the forward adaptive and reversing self-adaptive, and then combine the previous read out fault code 18149 a clutch pressure to adapt to the self-adaptive limit. The malfunction of this vehicle is caused by adaptive problems. Troubleshooting: the car is self-adaptive and self-adaptive learning according to the technical specifications. It has lasted for a long time. The data flow shows that the 2 adapts are finally successful. The fault is completely eliminated. When the D gear is idle, it can not only move forward, but also the vehicle runs up and does not shrug. This shows that the 2 self adaption of the automatic transmission is very important, so the maintenance of the automatic transmission should be combined with the data flow, and the maintenance is carried out according to the maintenance manual.