Yamaha MBK MW125 2014, Service Manual

Page: 341 / 380

FUEL INJECTION SYSTEM
8-44
Fault code No. 39
Fault code No. 39
Item Injector: open or short circuit detected.
Fail-safe system
Unable to start engine
Unable to drive vehicle
Diagnostic code No. 36
36
Actuation
Actuates injector five times at one-second intervals.
Illuminates the engine trouble warning light.
Procedure
Check that injector is actuated five times by listening for the operating
sound.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Connection of injector 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.
Execute the diagnostic mode.
(Code Nos. 36)
No operating sound
→
Go to
item 2.
Operating sound
→
Go to item
6.
2 Defective injector. Measure the injector resistance.
Replace if out of specification.
Refer to “CHECKING THE
FUEL INJECTORS” on page
8-67. Execute the diagnostic mode.
(Code Nos. 36)
No operating sound
→
Go to
item 3.
Operating sound
→
Go to item
6.
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.
Execute the diagnostic mode.
(Code Nos. 36)
No operating sound
→
Go to
item 4.
Operating sound
→
Go to item
6.
4 Wire harness continuity. Open or short circuit
→
Replace
the wire harness.
Between injector coupler and
ECU coupler.
Injector
orange/black–orange/black
Between injector coupler and
signaling system fuse terminal.
red/blue–red/blue
Execute the diagnostic mode.
(Code Nos. 36)
No operating sound
→
Go to
item 5.
Operating sound
→
Go to item
6.
5 Malfunction in ECU. Replace the ECU.
Refer to “REPLACING THE
ECU (engine control unit)” on
page 8-59.
6 Delete the fault code. Start the engine and let it idle
for approximately 5 seconds.
Check that the fault code num-
ber is not displayed.