PIAGGIO 500 cc Service Manual page 218

Fuel injection
Disconnect the digital instrument.
Keep the control unit disconnected.
Check continuity of the wire from the control
unit to the digital instrument.
Yellow (terminal 4/12) - 3 = 0 Ω (continuity)
YES
NO
Disconnect the connection between
the vehicle system and the fuel
injection system.
Repeat continuity control of the two
wires.
Terminal 4/12-yellow = 0 Ω (continuity)
Yellow-3 = 0 Ω (continuity)
Reset or replace the harness.
Check the earthing isolation of wire
3 - 23 >1MΩ (isolation)
YES
Repair or replace the harness.
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