What is the HOLD button in a car?
2 Answers
HOLD means to maintain. After pressing this button, the automatic transmission enters the hold mode, and the hold mode indicator light on the dashboard will illuminate. The HOLD button adjusts the optimal driving state according to different road conditions, effectively preventing the transmission from frequent shifting. During overtaking, it forces downshifting and prevents upshifting. The working principle of an automatic transmission is as follows: After the engine starts, the crankshaft drives the pump impeller to rotate through the flywheel. The centrifugal force generated by the rotation causes the working fluid between the pump impeller blades to be thrown from the inner edge to the outer edge. When the turbine speed is relatively low, the working fluid flowing out of the turbine moves backward and impacts the front of the stator blades. Since the stator is restricted by the one-way clutch and cannot rotate backward, the stator blades redirect the backward-flowing working fluid to push the pump impeller blades forward, promoting the rotation of the pump impeller and thereby increasing the torque acting on the turbine. As the turbine speed increases, the circumferential velocity becomes larger. When the resultant velocity of the tangential speed and circumferential velocity starts to point toward the back of the stator blades, the torque converter reaches the critical point. When the turbine speed further increases, the working fluid will impact the back of the stator blades. The HOLD function can be used in the following situations: Slippery roads: For example, starting on snow. Starting in snow with 2nd gear instead of 1st gear is more stable. When starting on snow, you can place the gear lever in position 2 and press HOLD, so the transmission will maintain the gear ratio of 2nd gear, making the start smoother. Continuous curve driving: When driving on continuous curves, the automatic transmission in normal mode may shift frequently due to the driver's control of the accelerator pedal. Pressing the HOLD button in D4 gear enters the hold mode, and the transmission will stay in 3rd gear, not only reducing transmission wear but also allowing the transmission to continuously output greater torque during driving, improving acceleration performance and making the ride smoother. Mountain roads or continuous slopes: Pressing the HOLD button in D4 or 2nd gear enters the hold mode. When going uphill, acceleration becomes more powerful. When going downhill, the drag is greater and safer, and it also avoids wear caused by frequent shifting of the transmission.
The Hold button in the car is essentially an automatic brake hold function. I often use it to give my foot a rest while driving, especially when stuck in traffic or stopping at red lights. When you press this button, the system helps maintain the braking state to prevent the vehicle from rolling, which is particularly useful on slopes. For example, when I drove my brother's car on a steep mountain road waiting at a traffic light, pressing the Hold button activated the system as shown on the dashboard, and the car stopped firmly without rolling back. I could take my foot off the pedal without any issues. A gentle press on the accelerator automatically released the brake and started the car, making the whole process much smoother and saving me from the fatigue of constantly pressing the brake pedal. This feature is quite common in modern cars, sometimes called Auto Hold or Brake Hold, but they serve the same purpose. It requires the vehicle to be in D gear or neutral with a firm press on the brake to activate, and with some practice, it becomes easy to use. I think for beginners or city drivers, this button is a blessing, reducing the stress during starts and lowering the probability of accidents.
