PIAGGIO 633823 Service Station Manual page 170

Injection
Check the power supply line of the injection load
remote control energising coil: after switching to
"ON", make sure there is battery voltage, for two
seconds, between the Red-White cable and Black-
Violet cable of the remote control base. If there is
not, check the continuity of the Red-White cable
between the fuse box and the remote control base
and of the Black-Purple cable between the pin 20
of the control unit and the remote control base.
N.B.
CONTINUITY TESTS MUST BE CARRIED OUT
WITH THE COMPONENTS DISCONNECTED.
(REMOTE CONTROLS, CONTROL UNIT,
FUSES ETC.).
INJEC - 18
MP3 250 i.e.