3232923 - 3340A abs check/adjustment devices

ELECTRO-HYDRAULIC UNIT

It consists of an electronic control unit (1) and an electro-hydraulic control unit (2).

Electronic control unit

The electronic control unit is responsible for:

  • acquiring the data coming from the 'active' wheel rpm sensors
  • storing control parameters defined during the preparation of the vehicle
  • storing the control software
  • processes downloaded data
  • controls the braking process
  • detecting failures at the braking system components
  • stores the fault codes and activates the A.B.S. warning lights.
  • transmitting and receiving data via the diagnostic connector.

Hydraulic control unit

The electro-hydraulic control unit consists of:

  • eight two-way solenoid valves
  • a dual circuit electric recovery pump
  • a low pressure accumulator
  • a high pressure accumulator

Responsible for modulating the pressure of the fluid at the brake calipers via two solenoid valves with the following stages:

  • brake fluid pressure increase
  • brake fluid pressure maintenance
  • brake fluid pressure discharge.

The letters indicating to which caliper and to which brake pump outlet they should be connected at stamped on the control unit at each outlet.

  • RR = to the right rear brake (pipe marked with a light blue coloured band)
  • LR = to the left rear brake (pipe marked with a green coloured band)
  • RF = to the right front caliper (pipe marked with a yellow coloured band)
  • LF = to the left front caliper (pipe marked with a white coloured band)
  • MC1 = from the main circuit/flange side pump (pipe marked with a black or pink coloured band when the pipe polyammide resin is black)
  • MC2 = from the secondary circuit/front pump (pipe marked with a brown coloured band).

Active sensors

They consist of two basic elements:

  • a magnetic multi-polar codifier (1) integrated in the 'instrument' wheel hub bearing
  • a Hall-effect receiver (2) opposite the codifier.

The adoption of active sensors offers the following advantages:

  • it reduces sensitivity to electro-magnetic interference
  • resists interference generated by road surface heating
  • it saves weight and size
  • it simplifies the transmission couplings through the elimination of the phonic wheels.