PIAGGIO 500 cc Service Manual page 144

Fuel injection
Using special tool 020481Y check the under-panel feed
Commutator set to "ON", switch set to "RUN",
PIN 26= battery positive; PIN 23= battery negative
Control unit with under panel feed is correct
If lack of feed is revealed in only one component,
check the connector concerned.
If the anomaly concerns both the decoder and the
control unit, disconnect the connector linking the
vehicle system and the fuel injection system.
White-black wire on terminal, fuel injection side =
continuity with pin 26 of the control unit and n° 8 of
the decoder.
Side stand raised, commutator set to "ON",
Terminal vehicle system side white-black wire = battery positive tension
YES
9 - 32
YES
of the control unit.
side stand raised.
YES
YES
switch set to "RUN".
NO
NO
NO
NO
Repair the connection or
harness