ABS - Functional description

Functional description

The ABS electronic control unit M50 is supplied (at pin 2 and 3) directly by the battery via a line protected by maxifuse F5, housed in the engine compartment junction unit B1.

The ignition-operated supply (INT/A) reaches pin 18 from the line protected by the fuse F42 of under facia control unit B2.

The control unit is earthed at pins 1 and 4.

The four sensors K70, K71, K75, K76 send wheel speed signals to pins 15-16, 10-9, 17-6 and 19-8 of M50 respectively.

Brake pedal switch I30 sends an enablement signal to pin 20 of control unit M50: the ABS cannot intervene unless the brake pedal is pressed. The switch I30 is supplied when the ignition is switched on (INT) from fuse F37 of junction unit B2.

Pin 23 di M50 emits a discrete speed signal that is sent tol Body Computer M1; the same signal is also copied via the CAN network.

Pins 15 and 26 of ABS control unit M50 connect to engine management control unit M10, Body Computer M1 and instrument panel E50, via the CAN line, to control the ABS failure warning light; if the problems involve the EBD function, the insufficient brake fluid and handbrake applied warning light comes on in addition to the ABS failure warning light.

If the instrument panel detects a fault in the ABS failure warning light, the general failure warning light is lit up.

Self-diagnostic data can be read by connecting to connector C of Body Computer M1- pin 1: it receives signals from pin 11 of the control unit M50 via the special diagnostic line.See E8010 DIAGNOSTIC MULTIPLE CONNECTOR