The CODE control unit
M20
is supplied
at pin 3 by the battery from the line for the maxifuse EFI (UGD)
of
B5
and is protected by fuse
B35
.
The supply controlled by the ignition (15/54)
reaches pin 8 through the line protected by fuse
B25
.
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.
It is possible to 'read' the control unit
autodiagnostic system, by connecting to the autodiagnostic connector
R10
from pin 5 of the control unit
M20
.
The autodiagnostic system also produces
the signal for the 'CODE failure' warning light, located in the
instrument panel
E50
: it involves an earth signal coming
out of pin 2 of the control unit
M20
.
The instrument panel
E50
is controlled
by the ignition (INT) at pin 19 of connector A from the line protected
by fuse
F1
of the junction unit
B1
: when an earth
signal reaches pin 6 of connector B, 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 the insertion and rotation of a key with a transponder.