What are the reasons why a manual transmission car suddenly cannot shift gears?

[StAaron]

Manual transmission cars may suddenly fail to shift gears due to reasons such as a dead battery, fuel quality issues, lack of antifreeze, or failure of the P-gear lock solenoid valve. The details are as follows: Dead battery: This could be caused by leaving the headlights on for an extended period, resulting in a drained battery, or the battery's lifespan may have expired. It is generally recommended to replace the battery every 2 years. Additionally, installing xenon headlights, high-power audio systems, or DVD players can also lead to vehicle circuit failures. Fuel quality issues: If there is water or sediment in the fuel tank, it is essential to refuel at reputable gas stations. When traveling, you can use a gauze over the fuel nozzle to filter out impurities. Lack of antifreeze: Some car owners add water or low-quality antifreeze to their vehicles, which can cause the entire cooling system to freeze in extremely cold winter conditions. This can lead to the engine cracking, the car's water pump failing to operate, difficulty starting the engine, and damage to other engine components.