VESPA GTS Super 125 i.e. Service Station Manual page 178

Injection
Install the electronic control unit interface wiring.
Start the engine and warm up until the electric fan
switches on.
Use an analogue multimeter with a direct voltage
scale measuring down to 2 V.
Place the tips of the multimeter between pins 4 (-)
and 11 (+)
With the engine running at idle speed, check that
the voltage oscillates between 0V and 1V
With the throttle valve completely open, the volt-
age is approx. 1V.
During the closing phase, the voltage is approx.
0V.
If the voltage remains constant, the sensor may be
damaged. Remove the sensor and check that
there are no oil or carbon deposits inside it..
SIGNAL CONTROL
THE FOLLOWING INFORMATION REFER TO THE VERSION EQUIPPED WITH MIU G3 ECU.
1. Lambda probe
Install the electronic control unit interface wiring.
Start the engine and warm up until the electric fan switches on.
Use an analogue multimeter with a direct voltage scale measuring down to 2 V.
Place the multimeter probes between pins 11 (-) and 12 (+).
INJEC - 178
Vespa GTS Super 125 i.e.