What is the fault that the automatic transmission can't upshift?

The failure of automatic transmission to upshift is caused by improper adjustment of throttle cable or throttle position sensor. The following is an introduction about the automatic transmission's failure to upshift: 1. Other causes of failure: (1) The governor is faulty and the oil circuit of the governor leaks oil. (2) The speed sensor is faulty. (3) The second brake or high-grade clutch is faulty. (4) The shift valve is stuck or the gear switch is faulty. 2. Troubleshooting method: (1) The sensors that affect the shift control are throttle position sensor and vehicle speed sensor. Find the cause of the fault according to the displayed fault code. (2) Check the speed sensor. If it is damaged, it should be replaced. (3) Check the gear switch signal. If there is any abnormality, it should be adjusted or replaced. 3. Note: The automatic transmission should be replaced in time. When changing the automatic transmission, the original engine oil should be kept as clean as possible. The automatic gearbox should strictly control the fuel quantity. Clean the clutch and brake in time after ablation. The hydraulic system of the torque converter has two oil inlet holes, one at the bottom of the control valve body.