What causes the clicking sound when starting with auto hold?
2 Answers
When starting with auto hold, the change in the vehicle's pitch attitude causes the friction pads and brake discs to creep or have a tendency to creep, resulting in a "creaking" sound, rather than the sound produced by the engagement of the internal clutch in the transmission. Here is the relevant information: 1. Auto Hold: When auto hold is activated and encountering a traffic light intersection, the driver steps on the brake pedal to stop, and the transmission is in the N (neutral) state (clutch disengaged). The driver lightly presses the accelerator, and the transmission shifts from N to D (drive), with the clutch engaging to provide power output before automatically releasing. This sound has no impact on the vehicle's functionality or lifespan, nor does it affect performance, so please use it with confidence. 2. Function: Auto Hold (AUTO-HOLD) is an extension of the Electronic Stability Program (ESP) functionality, which controls the braking of all four wheels through the ESP system.
When the auto-hold starts, there's a clunking sound. I reckon this is pretty common, so first check the braking system. Worn brake pads or dust stuck in them can cause friction and produce a clunking sound when released. If the car is frequently started with auto-hold on steep slopes, internal components like pistons or calipers may lack lubrication, leading to noise over time. The drivetrain also needs attention—if there's increased play in the half-shaft or driveshaft, a sudden release of force during startup can cause noise. Suspension issues, like aging shock absorbers or loose springs, can also lead to noise when the body shakes during startup. I recommend checking if the brake fluid is old and performing regular maintenance to lubricate key components, preventing minor issues from worsening—safety first. If the noise persists, it's best to visit a professional shop for diagnostic tools to rule out faults—don't try to fix it yourself.
