PIAGGIO 500 cc Service Manual page 179

Reconnect the phase-revolutions sensor.
Repeat resistance control through the fuel
injection harness on pins 7 - 12.
7-12 = 680 ± 15 %
The value must be very near to that revealed
directly to the sensor.
YES
Measure the alternate tension between pins 7 and
12 with the engine in starting speed.
7-12 = 0.8 - 4.5 V~eff
Revolutions speed = ~300-400 rpm
YES
The sensor circuit conforms.
If the anomaly of failed ignition persists,
replace the control unit.
NOTE
- During repairs install the sensor cable correctly .
- Do not force the cable.
- A poor shielding of the cable may prejudice the functioning of the engine at high speed.
YES
NO
Greater or infinite resistance.
Control the connectors accurately.
Disconnect and check continuity between
the connector and pins 7 and12
Connector-7 = continuity
Connector-12 = continuity
Repair the connectors or replace the harness.
Check the earthing isolation again.
7-23 = infinity (>1MΩ)
YES
Check the sensor and control unit
connectors.
Repair or replace the fuel injection harness
NO
Check the air gap and magnetic activity of
the sensor.
See: Chapter. 7-THERMAL UNIT AND
TIMING SYSTEM
If magnetic activity is zero, replace the
sensor.
Fuel injection
NO
Resistance 0 Ω
Repair or replace
the fuel injection
harness (short
circuit)
NO
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