3234790 - E7020 ABS - Description
Description
The electronic anti-lock brake system (BOSCH 5.3 ABS) governs braking pressure sent to the wheels and prevents loss of grip under all tyre and road surface conditions.The system is designed to complement the normal mechanical braking system and not to replace it. In this way it ensures effective safety in the case of anomalies: the ABS uses the same fluid as the conventional mechanical braking system.Four sensors fitted to the four wheels inform the electronic control unit of wheel speed at every moment. In this way, they detect wheel lock, wheel slip and loss of grip.Under these conditions, the control unit sends specific instructions to solenoids that modulate hydraulic circuit pressure to eliminate lock and restore the car to within grip limits. This ensures the shortest possible stopping distance, without losing control of the steering.Two adjustment solenoids (one for pressure charging, the other for pressure discharging) are fitted for each wheel.The sensors are active, i.e. they consist of a Hall-effect receiver that faces a magnetic coding device built into the hub bearing. Under these conditions, the signal is less influenced by electromagnetic interference and temperature.The control unit also controls brakeforce distribution over the rear axle and thus replaces the mechanical lload proportioning valve used previously (EBD function: Electronic Brake Distribution).The control unit is equipped with a self-diagnostic function: when an error occurs in the ABS system, a warning light is turned on and the system is simultaneously deactivated. Under these conditions, the car brakes using only the conventional system.When the control unit detects an error in the EBD function, it simultaneously turns on the 'insufficient brake fluid level' and 'handbrake on' warning light as well as the ABS warning light.Under these conditions, the rear brake distribution control is also deactivated and the car must be driven with great care. For further details see Characteristic of working principle 3340 A(B.S. ANTI-LOCK BRAKING SYSTEM .) . The supply lines to the control unit and the various system components (sensors and actuators) are protected by a specific maxifuse and other jumper fuses, located next to the junction unit. | for versions equipped with the 'VDC' function, refer to the special wiring diagram See E7022 VDC with the ABS BOSCH 5.7 system. |