b.Burnt fuse
c.Remote control switches
d.Connectors
B: Chassis ground
C: Fuel system
a. Faulty fuel pump
b.Dirty fuel filter
D: Ignition system
a. Faulty spark plug
b.Faulty coil
c.Faulty screened cap
E: Intake circuit
a. Air filter dirty
b.Dirty by-pass circuit
c.Faulty stepper motor
F: Other
a. Wrong distribution timing
b.Incorrect idle speed carburetion
c.Incorrect reset of the throttle valve position sensor
2 MIU system faults may be caused by loose connectors. Make sure that all connections have been
correctly made.
Check the connectors taking into consideration the following point:
A check that the terminals are not bent.
B check that the connectors have been properly connected.
C - Check whether the malfunction can be fixed by shaking the connector slightly.
3 Check the entire system before replacing the MIUIf the fault is fixed by replacing the MIU, install the
original control unit again and check if the fault occurs again.
4 Use a multimeter with an internal resistance of more than 10K Ohm /V when troubleshooting. Instru-
ments that are not suitable might damage the MIU central control unit. Use instruments with definitions
over 0.1V and 0.5 W , the precision must be greater than 2%.
1. Before fixing any part of the injection system, check to see if there are any registered faults. Do not
disconnect the battery before checking for faults.
2. The fuel system is pressurised at 250 kPa (2.5 BAR). Before disconnecting the fast-release fitting of
the fuel supply pipe, check that there are no naked flames. Do not smoke. Act with caution to avoid
spraying fuel to your eyes.
3. When fixing electric components, operate with the battery connected only when actually required.
4. When functional checks are performed, check that the battery voltage is over 12V.
Injection Vespa LX - S 125 3V ie 150 3V ie (2012)
INJEC - 178