Yamaha MBK MW125 2014, Service Manual

Page: 337 / 380

FUEL INJECTION SYSTEM
8-40
Fault code No. 30
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Installed condition of O
2
sensor. Improperly installed sensor
→
Reinstall or replace the sensor.
Start the engine, warm it up,
and then race it.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 2.
2 Connection of O
2
sensor cou-
pler.
Check the locking condition of
the coupler.
Disconnect the coupler and
check the pins (bent or broken
terminals and locking condition
of the pins).
Improperly connected
→
Con-
nect the coupler securely or re-
place the wire harness.
Start the engine, warm it up,
and then race it.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 3.
3 Connection of wire harness
ECU coupler.
Check the locking condition of
the coupler.
Disconnect the coupler and
check the pins (bent or broken
terminals and locking condition
of the pins). Improperly connected
→
Con-
nect the coupler securely or re-
place the wire harness.
Start the engine, warm it up,
and then race it.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 4.
4 Wire harness continuity. Open or short circuit
→
Replace
the wire harness.
Between O
2
sensor coupler and
ECU coupler.
gray/red–gray/red
Start the engine, warm it up,
and then race it.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 5.
5 Check fuel pressure. Refer to “CHECKING THE
FUEL PRESSURE” on page
7-3. Start the engine, warm it up,
and then race it.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 6.
6 Defective O
2
sensor. Check the O
2
sensor.
Replace if defective.
Refer to “ENGINE REMOVAL”
on page 5-3.
Start the engine, warm it up,
and then race it.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 7.
7 Malfunction in ECU. Replace the ECU.
Refer to “REPLACING THE
ECU (engine control unit)” on
page 8-59.
Fault code No. 24
Item
O
2
sensor: no normal signals are received from the O
2
sensor.
Fault code No. 30
Item Latch up detected.
Fail-safe system
Unable to start engine
Unable to drive vehicle