PIAGGIO 500 cc Service Manual page 205

Fuel injection
NO
NO
Repair or replace the harness.
YES
Connect the stepper connector.
Repeat continuity control of the tool pins.
14-24 = ~ 51 Ω
6-21 = ~ 51 Ω
NO
Check the harness and connectors more accurately.
YES
Connect the control unit connector.
Set ignition to position "ON" with switch on "RUN" and side stand raised.
Repeating the communications "ON" "OFF" "ON",
check the presence of tension pulses on the
command wires of the stepper.
Arrange continuous tension measurements.
14-24 = V (pulses for a few seconds)
6-21 = V (pulses for a few seconds)
NOTE
9
The pulses serve to modify the stepper position.
On reaching optimum position feed tension
becomes zero.
YES
NO
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