ABS electronic control unit
M50
is
supplied (at pins 2 and 6) directly by the battery via a line protected
by the ABS maxifuse, located directly on the battery
A1
-
connector C.
The supply controlled by the ignition (15/54)
reaches pin 23 from the line protected by fuse
F6
of the
additional fuse box
B98 A
.
The control unit is earthed via pins 1 and
5.
The four sensors
K70, K71, K75, K76
send
wheel speed signals to pins 12-28, 16-15, 14-13 and 30-31 of
M50
respectively.
Brake pedal switch
I30
sends a 'pedal
depressed' enablement signal to pin 32 of control unit
M50
:
the ABS cannot intervene unless the brake pedal is pressed.
If the control unit
M50
detects problems
relating to the ABS function, it sends the speedometer
E10
a
signal from pin 22, which lights up the 'ABS failure' warning light;
if the problems concern the EBD function, the handbrake warning
light is lit up from pin 38 of
M50
.; these are earth signals,
and they cause the warning lights to come on, as the instrument
E10
supply
is controlled by the ignitionnn (INT) from the line protected by
fuse F4 of the additional fuse box
B99B
.
Pin 37 of
M50
produces a speedometer
signal (average speed of all four wheels) which is sent to the instrument
panel
E10 See E4021 SPEEDOMETER
.
The autodiagnostic data can be read by connecting
to connector
R10
: it receives signals from pin 11 of the
control unit
M50
via the special diagnostic line.