What causes the sound when pressing the brake in P gear?
3 Answers
It is normal to hear a sound when pressing the brake in P gear. This is because the gear lock switch is equipped with an electromagnetic switch on the brake pedal after the vehicle is started to prevent misoperation and potential traffic accidents. Only when the brake is pressed will the locking device disengage, allowing gear shifting. Therefore, the sound is produced when the electromagnetic switch engages upon pressing the brake. More information about car gear shifting is as follows: 1. Shifting from P gear to any other gear requires pressing the brake, as this is a safety feature to ensure driving safety. 2. The moment the gear is shifted from P to R or D, the car immediately gains a driving force backward or forward, and the handbrake alone may not be sufficient to stabilize the vehicle, which could lead to danger. 3. Manufacturers now design unlock buttons that prevent shifting from P gear to other gears without pressing the brake.
My car makes a clicking sound when I press the brake in P gear, and I've been thinking about it for a long time. Actually, this is the transmission's locking mechanism in action. When you press the brake, the small hook separates from the gear, similar to a door latch releasing. This is common in automatic transmissions, especially in Japanese cars where the sound is particularly crisp. If the sound turns into a harsh metal scraping noise, it might indicate that the hook is worn or lacks lubrication, and it's best to have it checked at a shop. My old Accord started making a noticeably duller sound after 100,000 kilometers, and the technician fixed it by spraying some lubricant on the locking mechanism, costing less than 200 yuan. However, the sound is most noticeable during cold starts and becomes much quieter after driving for a while when the car warms up.
Last time during maintenance, I specifically asked the technician about this abnormal noise issue. He said that in P mode, there's a pawl in the transmission that locks the gear, and when you press the brake, the hydraulic unlock causes a mechanical collision sound. The key is to listen to the frequency of the sound—if it happens every time you press the brake, it's normal; if it only happens occasionally, you should pay attention. My car used to make a particularly loud noise, but later I found out it was because the floor mat was too thick and blocked the brake pedal from returning. After trimming a piece off, the problem was solved. The technician also reminded me that if you experience gear shifting hesitation or dashboard warning lights at the same time, it's likely the solenoid valve is faulty. Usually, shifting to N mode at red lights can reduce wear on the P mode mechanism, but most owners find it troublesome, and I often forget too.
