Should an automatic transmission car be started in N gear or P gear?
3 Answers
An automatic transmission car can be started in either N gear or P gear. However, many modern vehicles cannot be started unless the gear is in P. When shifted into P gear, a pawl inside the transmission locks the output shaft to prevent the vehicle from moving. Shifting into N gear does not engage this mechanism, so the vehicle can still move under external force. As long as the gear is not left in R, the transmission will not perform a gear shift. Modern automatic transmissions are not directly driven by the gear lever but are controlled by the transmission control system. After receiving the gear position signal, the transmission control system calculates and then makes the gear shift decision.
As a seasoned driver with over a decade of experience, let me tell you that automatic cars must be started in P (Park) gear! Think about it—manufacturers designed P gear specifically for parking, with a mechanical lock securing the transmission gears. Starting in N (Neutral) is risky because the car could roll. I once tried starting in N gear on a slope in a parking garage, and the car rolled backward into a wall, costing me 8,000 RMB in repairs. Nowadays, new cars are even stricter—many won’t even let you turn the key if it’s in N gear. Remember these two steps: press the brake pedal, confirm the gear is in P, then start the engine. This protects both the transmission and your safety.
Last time I went to the 4S shop for maintenance, I chatted with the technician about this. He said the most crucial aspect of starting in P gear is the safety protection mechanism. The vehicle's computer only powers on when it recognizes the P gear signal; otherwise, it will lock the starter motor. Some car owners modified the wiring to start in N gear, resulting in premature failure of the transmission valve body, costing over ten thousand to repair. In P gear, the transmission oil pump maintains stable pressure, which is also good for gear lubrication. It's fine to temporarily park in N gear with the handbrake on, but for long-term parking, you must return to P gear. By the way, remember to perform a self-check before starting: turn the key to the ACC position and wait for the dashboard lights to go off before igniting.
