PIAGGIO 500 cc Service Manual page 173

The electrical circuit of the injector is continuous.
If the anomaly persists check the control unit connector.
If necessary replace the control unit.
Disconnect the connector between the vehicle system and the fuel injection system.
Check resistance between pin 13 and the terminal
of the black-green wire on the connector fuel
injection system side.
13-black-green = 14.5Ω ± 5% (injector resistance)
YES
Check continuity of the black-green wire in
the vehicle system section.
Check the connector accurately between
vehicle system and fuel injection system.
Repair or replace the harness.
Check the earthing
isolation of the negative
wire of the injector.
Control unit and injector
connectors disconnected
13-23 = Ω infinity
NO
Repair or replace the
harness
Repeat checks.
Disconnect the connector to the control unit.
There is no continuity
Disconnect the connector and repeat resistance
controls directly on the injector terminals.
Resistance =14.5Ω ± 2%
YES
Fuel injection
NO
NO
NO
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