(1) For the vacuum brake booster of the hydraulic brake system, compressed gas in the piston type accumulator leaks from the piston seal via brake fluid. If this problem is left unattended, the amount of gas decreases, and pressing the brake pedal can cause abnormal noise in the passenger compartment. (2) When shifting the gear from 'P' after starting engine while brake fluid pressure inside the brake pipe is low, such as at the time of pressing the brake pedal after stopping the engine, the warning buzzer for the vacuum brake booster may start to sound even if there is nothing to warn about. (3) The warning buzzer for low brake fluid pressure may start to sound even if the pressure is not low because the switch activation setting is not appropriate for the pressure on certain vehicles.
