What's the reason for an automatic transmission car not being able to shift gears?

[StNatalie]

There are several reasons why an automatic transmission car cannot shift gears: the gear lock is engaged, the P gear locking mechanism is stuck and cannot reset, the shift solenoid is damaged, or the control computer malfunctions. Gear lock engaged: If the gear lock is engaged or stuck, the gear lever will inevitably be unable to shift. In this case, you can try unlocking the gear lock with a key. If that doesn't work, check the brakes. While pressing the brake pedal, observe whether the brake lights come on. If the brake lights do not illuminate, it indicates a faulty brake switch. The car's computer cannot detect whether the brake is pressed, thus preventing gear shifting. The brake switch needs to be replaced promptly. P gear locking mechanism stuck and unable to reset: The transmission P gear locking mechanism consists of a locking gear, a locking pin, and a set of action mechanisms. When the gear lever is moved to the P position, the cable drives the connecting ball pin, causing the working pin to slide and engage the locking pin pawl with the parking gear, thereby achieving parking lock. If the P gear locking mechanism is stuck and cannot reset, it needs to be manually reset. Shift solenoid damaged: When the shift solenoid is damaged, it cannot execute the shift command. In this case, a repair shop should be consulted to replace the solenoid. Control computer malfunction: In this situation, it is necessary to contact a 4S shop or repair shop for professional maintenance.

[KaydenMarie]

I've encountered situations where an automatic transmission car couldn't shift gears on the road, which was quite frustrating. This could be due to insufficient or dirty transmission fluid affecting the shifting function, especially in older cars if regular oil changes are neglected. Additionally, faults in the electronic control system might prevent the computer from responding correctly, such as a broken sensor or malfunctioning control module. Sometimes, the linkage under the gear lever gets stuck, or a dead battery causes the entire system to fail. I recommend first trying to restart the engine to see if the situation improves. If that doesn't work, pull over immediately and turn on the hazard lights. Avoid forcing the gear shift as it could damage the transmission. Regular maintenance should include checking fluid conditions to prevent such troubles, unlike my friend who ended up spending a fortune on major repairs.