The ABS electronic control unit
M50
is supplied (at pins 2 and 6) directly by the battery via a line
protected by maxifuse F4, housed in the engine compartment junction
unit
B1
.
The ignition-operated supply (INT/A) reaches
pin 23 from the line protected by the fuse F42 of under facia control
unit
B2
.
The control unit is earthed via pins 1 and
5.
The four sensors
K70, K71, K75, K76
send
wheel speed signals to pins 28-12, 15-16, 13-14 and 30-31 of
M50
respectively.
Brake pedal switch
I30
sends an
enablement signal to pin 32 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
.
The 'ASR OFF' control button on panel
H35
sends a deactivation signal to pin 27 of
M50
, while pin
18 viene relays a signal that turns on a led on panel
H35
when the system is off.
Pin 37 di
M50
emits a discrete speed
signal that is sent tol Body Computer
M1
; the same signal
is also copied via the CAN network.
Steering sensor
K58
is supplied
by ABS control unit
M50
at pin 39 and receives a reference
earth from pin 21: the signal that detects sudden changes in steering
direction is sent via the CAN line to engine control unit
M1
and ABS control unit
M50
.
Yaw sensor
K74
is supplied from
ABS control unit
M50
at pin 39, while it receives a reference
earth from pin 21: control and command signals are exchanged with
ABS control unit
M50
, at pins 8, 9, 10 and 41.
Pressure sensor
K72
is supplied
from ABS control unit
M50
at pin 42, while it receives a
reference earth from pin 25: the pressure detection signal is sent
to pin 26 of ABS control unit
M50
.
Pins 24 and 40 of ABS control unit
M50
connect to Body Computer
M1
and instrument panel
E50
to control the ABS warning light and - if the problem lies in the
EBD function - the low brake fluid level and handbrake warning lights.
The VDC and ASR functions manage the relevant warning light as described
previously.
Self-diagnostic data can be read by connecting
to connector G of Body Computer
M1
- pin 1: it receives
signals from pin 11 of control unit
M50
via a special diagnostic
line.