What are the reasons for an automatic transmission car not shifting up?

[OJackson]

Here are several reasons why an automatic transmission car may not shift up: 1. Improper adjustment of the throttle cable or throttle position sensor: Inspect and adjust the throttle cable and throttle position sensor to resolve the issue. 2. Faulty vehicle speed sensor: Check the vehicle speed sensor and replace it if necessary. 3. Stuck shift valve or faulty gear position switch: Inspect the gear position switch signal. If there are no faults in the control system, the automatic transmission should be disassembled for inspection. Additional information: Here is an introduction to automatic transmissions: 1. The automatic transmission must be filled with the manufacturer-specified automatic transmission fluid. Manual transmission gear oil, differential-specific oil, or engine oil must not be mistakenly added to the automatic transmission. Otherwise, after driving for a period, all clutches and brakes may suffer severe burning and corrosion. 2. The automatic transmission fluid should be replaced promptly. When changing the fluid, ensure the old fluid is drained as thoroughly as possible. The amount of fluid added to the automatic transmission must be strictly controlled. After the clutches and brakes are burned, the hydraulic system of the torque converter must be cleaned promptly, which has two oil inlet holes, one located at the bottom of the control valve body.