The CODE control unit
M20
is supplied at pin 3 by the
battery from the line for the maxifuse EFI of
B5
to 2/99
or
B99
from 2/99, through the line protected by fuse
B35
to
2/99 or by fuse
F5
of supplementary fuse box
B98A
from
2/99.
The supply controlled by the ignition (15/54)
reaches pin 8 from the line protected by shunt fuse
B25
to
2/99 or fuse
F4
of the additional fuse box
B98A
from
2/99.
Pin 4 is earthed.
The line leading from pin 6 is a serial
line leading to engine management unit
M10
, which is responsible
for identifying the key and exchanging codes.
The control unit is equipped with a self-diagnostic
unit that may be used by connecting the unit to connector
R10
:
this receives signals from pin 5 of control unit
M20
through
the tester line.
The self-test system also produces the signal
for the "CODE failure" warning light, located in the check
instrument
E30
, which comes out of pin 2 of the control unit
M20
.
The check module
E30
receives a supply
controlled by the ignition (INT) at pin 1 from the line protected
by fuse
B11
to 2/99 or from fuse
F4
of supplementary fuse
box
B98B
from 2/99: when this earth signal arrives, the "CODE
failure" warning light comes on.
A second control unit connector is connected
via two leads to the aerial, fitted coaxially to the ignition key,
in order to detect key insertion and rotation.