PIAGGIO 500 cc Service Manual page 140

Fuel injection
YES
The fuel injection
control unit is being
fed safely.
Interpose the special tool n° 020481Y between the
control unit and the fuel injection system. See page 9-8
Disconnect the main decoder connector
and check the following conditions:
terminal n° 3=positive battery
terminal n° 4= negative battery
Decoder basic feed correct
YES
9 - 28
NO
Check efficiency of 3A fuse n°3.
YES
YES
Eliminate any possible short circuit
of the harness and replace the fuse.
Check for a possible short circuit of
the decoder or control unit.
Replace if necessary
NO
NO
NO
YES
NO
YES