Components

The system also includes:

• hydraulic system lines;
• special electrical wiring;
• switch on brake pedal for measuring braking conditions;
• warning light (7), located on the control panel.

When in test mode (see paragraph on "Blink Codes"), the warning light (7) emits a series of blink codes to provide information on faults saved in the control unit CMOS EEPROM memory.

COMPONENTS

Electro-hydraulic control system

The hydraulic control unit consists of two sections fastened to one another: an electronic control unit and a hydraulic control unit.

The electronic control unit is connected to the wiring of the A.B.S. by means of a multiple connector with 31 terminals, of which 17 are used.

The electronic control unit governs the hydraulic unit by processing signals from the sensors with the aid of programs mapped in its memory.

The hydraulic control unit is connected to the brake pump and ABS components by means of the braking system pipes.

The main change compared to the previous model has been the replacement of three-way valves with two two-way solenoids on each wheel.

Compared to the previous version, the 5.3 unit is lighter and the valves are smaller. Valve opening and closure mechanism is more effective and size has been reduced further through the use of tiny microhybrid electronic circuits which are about 30% smaller than components used previously.

ELECTRONIC CONTROL UNIT

The electronic control unit is made up of hybrid circuits with integral resistances, diodes, transistors and logical circuits. The system is based on two CMOS microprocessors . Each runs the same program independently and monitors the another. Both receive the same input signals and process them independently. The electronic control unit sends an operational control to the hydraulic control unit only when both signals are identical.

Otherwise, if the ABS contains a fault for example, the device cuts itself out and braking takes place in conventional manner. The fault warning light on the instrument panel comes on at the same time.

Fault data are recorded in a non-volatile memory. One of the two microprocessors contains a CMOS EEPROM memory, which saves its contents even if the battery is disconnected. This memory saves fault codes so that they can be read using a tester during service.