Ignition switch H001 is supplied via the ignition at pin 2 connector A. The line is protected by maxifuse F70 housed in battery control unit B099 and a further fuse F03 housed in engine bay control unit B001.When the ignition is turned ON, the power supply passes through a line protected by fuse F16 located in junction unit B001 to reach engine mangement unit M010, pin 58 (pin B4 connector A for 2.0 petrol versions).CODE control unit M020 receives a key inserted code via transponder P091 and checks its validity by comparing it with codes stored in its memory.If the code is correct CODE control unit M020 enables control unit M010 to start the engine as soon as required and simultaneously controls activation of the warning light on instrument panel E050 by earthing pin 2 of its own connector B.