Abstract: A brake system includes a master cylinder which generates brake fluid pressure by a braking operation of a driver, an electric motor driven slave cylinder that generates brake fluid pressure according to an electrical signal based on the braking operation of the driver, a vehicle wheel cylinder for braking a wheel by the brake fluid pressure generated in the master cylinder or the slave cylinder, a brake light that informs a following vehicle of the operation of the wheel cylinder, and a first sensor and a second sensor that detect stroke positions of the brake pedal. During normal operation of the brake system the brake fluid pressure generated in the slave cylinder is transferred to the wheel cylinder. During abnormal operation of the brake system, the brake fluid pressure generated in the master cylinder is transferred to the wheel cylinder.

Abstract: According to the invention, the existence of residual pressure in the braking system is determined by means of continuous rough monitoring of the pressure in said system. If the existence of said residual pressure is established, then a fine monitoring process is carried out several times, whereby a pressure relieving body in the braking system is opened and sensed in order to determine whether the actual pressure is decreasing and if so to what extent.

Abstract: A condition of hydraulic fluid conducted from an accumulator to an operation device via a pressure control unit, is evaluated by determining a pressure (Pa) of the fluid in a flow path interconnecting the accumulator and the control unit, and determining a stabilization time (T) when an absolute value of a pressure gradient per unit time of the pressure falls below a predetermined value. A pressure drop (?Pa) of the pressure is determined during a period between a time (T0) when the pressure begins to decrease, or at a time before the time (T0) and the stabilization time (T). The pressure drop is compared with a predetermined pressure drop that is obtainable under normal conditions. An increase in (?Pa) can signify the entry of air into the hydraulic fluid, or a leakage of the hydraulic fluid.

Abstract: An instrument panel for a vehicle has an anti-lock braking system and a regenerative braking system. A method is used to control the brake system indicators on the instrument panel. If it is determined that an anomalous condition exists in either the anti-lock braking system or the regenerative braking system, a first indicator is illuminated in an amber color to alert the vehicle operator of this condition. If the anti-lock braking system is active, and there is no anomalous condition detected in the anti-lock braking system, a second indicator is illuminated in green to alert the vehicle operator that the anti-lock braking system is active. Control of the first and second indicators is provided in accordance with a hierarchal structure that gives priority to an anomalous condition in the anti-lock braking system.