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

[LaCarter]

Automatic transmission not shifting up may be caused by improper adjustment of the throttle cable or throttle position sensor, leading to governor failure. Diagnosis and repair methods: Perform fault self-diagnosis on the electronically controlled automatic transmission; readjust the throttle cable or throttle position sensor according to standards; inspect the vehicle speed sensor and replace if damaged; check the gear position switch signal and adjust or replace if abnormal; measure governor oil pressure - if it remains at 0 or very low when vehicle speed increases, it indicates governor failure or severe leakage in the governor oil circuit. Maintenance methods: The addition of automatic transmission fluid (ATF) must be strictly controlled. The ATF level must be between the bottom of the planetary gears and above the control valve body. When the fluid level is too high, the planetary gears' agitation will cause the ATF to foam, potentially leading to oil leakage during driving. When the oil level is too low, the clutches and brakes are prone to slipping.