What is the reason why an automatic transmission car cannot start in P gear?

[AmirAnn]

The reason why an automatic transmission car cannot start in P gear is: the starter motor of the car has malfunctioned. The meanings of the letters in an automatic transmission car are: P gear is the parking gear, R gear is the reverse gear, N gear is the neutral gear, D gear is the drive gear, L gear is the low gear, S gear is the sports mode, and OD gear is the overdrive gear. The precautions for driving an automatic transmission car are: 1. Do not shift into P gear while driving; 2. After driving, you must turn off the engine and shift into P gear to remove the key; 3. Do not shift into N gear to coast while driving; 4. Start the vehicle in P or N gear, shift the gear lever out of P gear while stepping on the brake, turn on the power and step on the brake to shift to N gear, and after ignition, shift into D gear to drive directly; 5. When switching between N, D, and L gears, there is no need to press the shift button. To shift from L gear to lower limit gears, press the shift button, but shifting from lower gears to higher gears does not require pressing the shift button.

[DiWilliam]

When dealing with car malfunctions, I often encounter issues where automatic transmission vehicles won't start in P gear. The main reasons could be a faulty gear position sensor, where the gear signal isn't transmitted properly, causing the computer to think the car isn't in park and preventing ignition. It could also be due to an aging battery with insufficient power, making the starter motor unable to turn, especially more common in cold seasons. Another possibility is problems with the starting system, such as worn ignition switch contacts or a blown fuse, interrupting the current. Additionally, if the oil pressure is insufficient or the oil pump is faulty, the engine won't start either. In such cases, it's best to first observe the dashboard—whether the lights are on can give a preliminary indication of whether the circuit is functioning. I recommend avoiding repeated attempts to start the car to prevent further damage and instead promptly seek professional help to diagnose the issue with a diagnostic tool. Regular maintenance of the battery and checking if sensor connectors are loose can help reduce such troubles. Don't forget to rule out simple factors one by one, such as using a multimeter to measure the battery voltage—if it's too low, charge or replace it.

[NoraAnn]

My car once had an issue where it wouldn't start in P gear with an automatic transmission. That time, the battery was completely dead, and I only heard clicking sounds when trying to start. Later, I learned that poor contact in the gear position sensor is also a common cause - if the gear lever doesn't send accurate signals, the safety system will lock the ignition. Additionally, the key ignition switch might be worn out, and replacing it could solve the problem. Starter motor failure is another possibility, often accompanied by unusual noises when it can't turn the engine. Using improper fuel can also affect starting. In my case, I had to get a jump start from a friend before going to the shop to replace the battery. To summarize: first check the battery, ensure the gear is fully engaged in P position, then watch for any warning lights. Don't delay repairs, as breaking down mid-drive is more troublesome, especially at night without lights, which poses significant safety risks.

[KingMarie]

From the perspective of driving safety, failure to start an automatic transmission car in P gear must be taken seriously. It could be due to abnormal sensor signals, where the gear position is not recognized, preventing ignition. Battery issues are one of the main causes, such as insufficient power or corroded terminals. Faults in the starting system, like relay failures, are also common and can result in no current flow. Additionally, clogged fuel lines or air entering the system can affect fuel supply. Immediately stop using the vehicle and check the dashboard display. If lights are on, it indicates the circuit is normal, and you should inspect the sensors or fuel lines. Contact a repair shop as soon as possible to avoid sudden travel interruptions that could pose safety hazards. Regular maintenance can help avoid costly repairs.