PIAGGIO 500 cc Service Manual page 219

Fuel injection
YES
Connect the control unit.
Ignition set to "ON"' with switch on "RUN" and side stand raised.
Measure the tension between pins 3 and 23 with
engine stopped.
3 - 23 = 9 - 10 V
NO
YES
Using the diagnosis tester carry out
a revolutions counter control.
Measure tension again.
3 - 23 = less than 1V for a few
seconds.
YES NO
The control circuit of the revolutions
Replace the fuel injection control unit.
counter is working.
9
9 - 107