PIAGGIO 500 cc Service Manual page 203

YES
Select the "active diagnosis" function from the
menu
Select "stepper" diagnosis
Activate the diagnosis with the engine
Check if the stepper commands any revolutions variation
and await the response of the diagnosis tester.
Test completed successfully
Revolutions variations perceived.
Stepper and related circuit are efficient.
Test completed successfully
No revolutions variation.
Remove the throttle body (see
Chapter. 7-THERMAL UNIT AND
TIMING SYSTEM).
Check cleanliness of the auxiliary
air circuit.
Set ignition from "ON" to "OFF" and
again to "ON" and check if
the piston valve moves.
NO
If the valve does not move, replace the throttle body.
See Chapter. 7-THERMAL UNIT AND TIMING SYSTEM.
NO
Check the coolant temperature sensor signal.
If necessary check the control unit.
warm and idling.
YES
NO
See page 9-74.
NO
Test failed
No revolutions variation
Fuel injection
9
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