Sym Citycom 300i - Fault Diagnosis

4. Fuel Injection System
4-33
Fault Diagnosis
EFi Circuit Inspection
Main
switch on
NG
NG
OK
OK
OK
OK
OK
NG
NG
NG
NG
OK
Check light extinguished after 2 seconds?
Battery voltage above 12.5V?
Battery voltage & ECU voltage of less than 0.2 V?
1. Main switch OFF
2. Removed ECU coupler
3. Main switch ON
4. Use voltage meter measurement of the power-pin
voltage difference
5. Confirmed ECU and battery supply voltage
differential pressure within the 0.2 V voltage
Battery voltage • drive parts voltage of less than 0.2
V?
1. Main switch OFF
2. Removed the injector, fuel pump, O
2
sensor, roll
over sensor, ignition coil couplers
3. Measurement of the voltage between the couplers
and ground of the voltage difference
4. Confirmed voltage difference and battery voltage
of 0.2 V gap within?
ECU 5V voltage - sensor voltage of less than 0.2 V?
1. Main switch OFF
2. Use probe inserted throttle sensor, engine
temperature sensor, the inlet pressure sensor
power connector
3. Main switch ON
4. Use voltage meter measurement of the sensor
connector voltage
5. Voltage standard value: 5.0‰0.1V
Battery voltage - fuel pump voltage of less than 0.2
V?
1. Main switch OFF
2. Removed fuel pump power coupler
3. Potential probe then pumped two-pin connector
4. Main switch ON
5. Pumped in three second record supply voltage
values
6. Confirmed pump and battery supply voltage
differential pressure within the 0.2 V voltage
1.
Bulbs broken?
2. Fuse broken?
3. Battery voltage is too low?
4. ECU Power line bad contact?
5. Poor contact the main power
switch?
6. ECU fault？
1.
Charging line abnormal?
2. Unable electrical storage
batteries?
3. Short-circuit leakage?
1. Lines abnormal?
1. Lines abnormal?
1.
Lines abnormal?
2. ECU abnormal?
1.
Lines abnormal?
2. Relay fault?
3. ECU abnormal?
End
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