Yamaha WR250F Owner's Service Manual page 381

TIP
Disconnect the fuel pump coupler when this diagnostic tool is used.
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Actuation
Procedure
Probable cause of malfunc-
Item
tion and check
1 Connection of injector cou-
pler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
2 Defective injector.
3 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
4 Wire harness continuity.
5 Malfunction in ECU.
6 Delete the fault code.
39
Injector: open or short circuit detected.
Unable to start engine
Unable to drive vehicle
36
Actuates injector five times at one-second intervals.
The engine trouble warning light and the "WARNING" on the
Yamaha diagnostic tool screen come on each time the injector is
actuated.
Check that injector is actuated five times by listening for the oper-
ating sound.
Maintenance job
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Measure the fuel injector re-
sistance.
Replace if out of specifica-
tion.
Refer to "CHECKING THE
FUEL INJECTOR" on page 9-
81.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Open or short circuit  Re-
place the wire harness.
Between injector coupler and
ECU coupler.
red/black–red/black
red–red/blue
Replace the ECU.
—
9-47
FUEL INJECTION SYSTEM
Confirmation of service
completion
Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 2.
Operating sound  Go to
item 6.
Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 3.
Operating sound  Go to
item 6.
Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 4.
Operating sound  Go to
item 6.
Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 5.
Operating sound  Go to
item 6.
—
Start the engine and let it idle
for approximately 5 seconds.
Check that the fault code
number is not displayed.