Why can't the car start when shifted to N gear while parking?

[WilliamAnn]

There are following reasons why the car cannot start when shifted to N gear while parking: 1. N gear is the neutral gear, and the car cannot be started in neutral. 2. Neutral refers to the state when the car's transmission is operating without any power transmission gear engaged. Relevant information about the N gear in cars is as follows: 1. N gear: It is one of the three standard gears in automatic transmission models, located between the R gear and D gear on the gearshift console, essentially serving as the neutral gear in the transmission. 2. Purpose: To cut off power transmission between the input shaft and output shaft inside the transmission. 3. Origin: The "N" in N gear comes from the first letter of the English word Neutral.

[DeManuel]

I was curious about this before too. Actually, it's a protective measure intentionally designed by manufacturers. The main reason automatic transmission cars must be in P (Park) to start is to prevent accidents from sudden movement if you start the engine in N (Neutral). For example, if your parking spot is on a slope and you start in N, what if you accidentally release the brake? The car could roll and hit a wall—how dangerous! Also, some careless drivers forget to engage the parking brake. If they start in N, the car could lurch forward immediately. Additionally, the P position has a locking pawl that secures the transmission, reducing impact during startup. Nowadays, many new cars won’t start even in N if the brake isn’t pressed. Though this design might be a bit inconvenient, it genuinely prevents many accidents. Safety first, after all!

[LaConnor]

I specifically asked an experienced car mechanic about this, and he said there are three main reasons: First, when starting in neutral, the transmission gears aren't locked, so the sudden impact force from the engine's operation is directly transmitted to the drivetrain, which can damage components over time; Second, it's an electronic system design issue - there's a gear position sensor in the car that only sends power to the starter motor when it detects a P (Park) gear signal; Third, it prevents accidental operation, as manufacturers prioritize preventing kids from randomly turning the ignition key. Actually, there's an additional benefit to starting in P gear when the engine is cold - it allows the transmission oil pump to work first and lubricate the gears for protection.

[LeIsabella]

Simply put, it's for safety. The P (Park) position has a mechanical latch that locks the transmission shaft, acting as a double safety measure for the vehicle. If you start the car in N (Neutral) gear, the engine power is directly transmitted to the wheels. If your foot slips off the brake pedal, the car could lurch forward unexpectedly. Last time my family went to the car wash, we saw someone start their car in N gear, resulting in a collision with the washing machine and costing them thousands in damages. Manual transmission cars can start in neutral because the clutch disengages the power transmission, but automatic transmissions lack this mechanism. It's advisable to develop the habit of checking the gear position before starting the engine to avoid any mishaps.