The CODE control unit
M20 is supplied
with power at pin 3 from the battery from the line of maxifuse EFI
B99, through a line protected by fuse F5 of the additional fuse
box B98 A.
The supply controlled by the ignition (15/54)
arrives at pin 8 from the line protected by fuse
F4
of the
additional fuse box
B98 A
.
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 13 from the line protected
by fuse F4 of supplementary fuse box B98B; 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.