223003374 - E7020 ABS - FUNCTIONAL DESCRIPTION

Functional description

The ABS electronic control unit M50 is supplied (at pins 9 and 25) directly by the battery via a line protected by ABS maxifuse F4 , housed in the engine compartment junction unit B01 . The control unit is earthed at pins 8 and 24.The four sensors K70 , K71 , K75 , K76 send wheel speed signals tp pins 1-2, 19-20, 5-6, 22-23 of M50 , respectively.The brake pedal switch I30 sends an enablement signal to pin 18 of the control unit M50 via a line going into the junction unit under the dashboard B02 and supplied by the line controlled by the ignition (INT) protected by fuse F37 . The entire operation of the ABS is, in effect, excluded unless the brake pedal I30 is pressed. The signal coming out of I30 is the same one which lights up the brake lights (     See E2021 BRAKE LIGHTS).The supply for the ABS control unit is controlled by the ignition by the line for fuse F42 at pin 13 of the control unit.If the ABS control unit identifies signals of possible faults, it notifies the body computer M01 (pins 6 and 16 of connector C)which, in turn, notifies the instrument panel E50 with the ''ABS failure'' warning light coming on via the CAN line from pins 5 and 6 of connector D. The supply for the body computer M01 is both controlled by the ignition and direct to pin 11 of connector E (INT) and pin A of connector C of the junction unit under the dashboard B02 . There is a protective fuse F1 for the direct supply located in the engine compartment junction unit B01 .These lines also supply the instrument panel dividing inside the junction unit under the dashboard B02 : These lines are protected by fuses F37 and F53 , respectively. Pins 8 and 9 connector D of the body computer M01 are connected to earth. This reference signal is also supplied to the panel via pin 36 of the body computer. The diagnostic line is connected to pin 1 connector B of the body computer M01 (    See E8010 DIAGNOSTIC MULTIPLE CONNECTOR).