Yamaha YZ450FP 2023, Owner'S Service Manual

Page: 332 / 388

FUEL INJECTION SYSTEM
8-33
Fault code No. 39
TIP
Disconnect the fuel pump coupler when this diagnostic tool is used.
7 Delete the fault code. Confirm that the fault code has
a condition of “Recovered”
using the Yamaha diagnostic
tool, and then delete the fault
code.
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
Actuation
Actuates injector five times at one-second intervals.
“WARNING” on the Yamaha diagnostic tool blinks five times when the
injector is actuated.
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 (for bent or bro-
ken terminals and locking condi-
tion of the pins).
Improperly connected

Con-
nect the coupler securely, or
repair/replace the wire harness.
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 6 and finish the service.
Condition is “Detected”

Go to
item 2.
2 Defective injector. Check the injector.
Refer to “CHECKING THE
INJECTOR” on page 8-55.
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 6 and finish the service.
Condition is “Detected”

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 (for bent or bro-
ken terminals and locking condi-
tion of the pins).
Improperly connected

Con-
nect the coupler securely, or
repair/replace the wire harness.
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 6 and finish the service.
Condition is “Detected”

Go to
item 4.
Fault code No. 33
Item
Ignition coil: open or short circuit detected in the primary lead of
the ignition coil.