Description of operation

DESCRIPTION OF OPERATION

The CODEcontrol unit M20 is upplied on pin 3 by the battery from maxifuse EFI line of B5.

The ignition switch power supply (15/54) arrives to pin 8 through the line protected by injection and Code memory fuse B35.

Pin 4 is connected to a "controlled" earth through injection control unit M10 (pin 16).

The line coming from pin 6 is the serial line connecting to the engine control unit ( pin 7 of M10) through which the key acknowledgement dialogue takes place and the code exchange.

Through this serial line it is also possible to "read" the control unit diagnostics system, connecting to the diagnostic socket for e.i. R20.

The diagnostics system also generates the signal for the "CODE fault warning light" located in cluster E50, by pin 2 of control unit M20.

Cluster E50 is powered through ignition switch(INT) to pin 5 of connector A from the line protected by fuse B11: when the earth signal arrives on pin 4 of connector B , the "CODE fault" warning light switches on.

A second connector of the control unit links up through two cables with the aerial, located coaxially on the ignition switch to be able to "sense"the insertion and turning of the key.

COMPONENTS