The ABS electronic control unit
M50
is supplied directly by the battery at pin 6 from the line protected
by ABS maxifuse B7, and at pin 2 from the line protected by maxifuse
B34
.
The ignition-operated supply (INT/A) reaches
pin 23 from the line protected by the fuse
B31
. The control
unit is earthed via pins 5 and 1.
The four sensors
K70, K71, K75, K76
send
the wheel speed sensors to pins 12-28, 15-16, 13-14 and 30-31 of
M50
respectively.
The brake pedal switch l30 is supplied when
the ignition is switched on by two specific lines, protected by
fuses
F5
and
F1
of the junction unit
B1
.
The switch l30 indicates to the control
unit M50 its operating state: if the pedal is pressed, the control
unit M50 receives the signal at pin 37, whereas with the pedal pressed,
the signal reaches pin 32.
Pin 33 of
M50
produces a speedometer
signal (average speed of all four wheels) which is directed to instrument
panel
E50
- pin 2 of connector B (
See E4010 INSTRUMENT PANEL
).
The ABS includes a self-diagnostic system:
when the control unit detects problems with the ABS, it sends a
signal from pin 20 of instrument
E50
- pin 18 of connector
C - which turns on the ABS fault warning light.
This warning light is managed by the processor
in the instrument panel
E50
, which receives and processes
the signal coming from the control unit
M50
.
If the problems line in the EBD function,
the control unit also sends a signal from pin 17 and 38 of the instrument
panl
E50 - pins 10 and 19 of connector C - to the low brake fluid and
handbrake warning light (
See
E4010
INSTRUMENT PANEL
).
Both the signals sent to the instrument
are earth signals, and they make the warning lights come on, as
the instrument panel
E50
is ignition activated (INT/A) from
the line protected by fuse
F1
of the junction unit
B1
.
The self-test data can be read by connecting
to pin 1 of connector
R10
: it receives signals from pin
11 of the control unit
M50
via the specific diagnostic line.